WO2021186334A1 - Hydro-solvo-thermal graphene oxide synthesis method - Google Patents

Hydro-solvo-thermal graphene oxide synthesis method Download PDF

Info

Publication number
WO2021186334A1
WO2021186334A1 PCT/IB2021/052158 IB2021052158W WO2021186334A1 WO 2021186334 A1 WO2021186334 A1 WO 2021186334A1 IB 2021052158 W IB2021052158 W IB 2021052158W WO 2021186334 A1 WO2021186334 A1 WO 2021186334A1
Authority
WO
WIPO (PCT)
Prior art keywords
graphene oxide
potassium
doped
solvo
hydro
Prior art date
Application number
PCT/IB2021/052158
Other languages
French (fr)
Inventor
Nanda Gopal Sahoo
Chetna Tewari
Sandeep Pandey
Manoj Karakoti
Sunil Dhali
Himani Tiwari
Gaurav Tatrari
Anand B Melkani
Original Assignee
Nanda Gopal Sahoo
Chetna Tewari
Sandeep Pandey
Manoj Karakoti
Sunil Dhali
Himani Tiwari
Gaurav Tatrari
Anand B Melkani
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nanda Gopal Sahoo, Chetna Tewari, Sandeep Pandey, Manoj Karakoti, Sunil Dhali, Himani Tiwari, Gaurav Tatrari, Anand B Melkani filed Critical Nanda Gopal Sahoo
Publication of WO2021186334A1 publication Critical patent/WO2021186334A1/en

Links

Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K33/00—Medicinal preparations containing inorganic active ingredients
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y40/00—Manufacture or treatment of nanostructures

Definitions

  • the present invention relates to the technical field of carbon structure production and, in particular, to a method for synthesis of graphene oxide to obtain potassium-doped graphene oxide for bio-sensing and bio-imaging.
  • Oak fruit Quercus ilex
  • oak fmit is treated as agricultural waste for the consumption by animals and is overlooked by human beings.
  • the chemical composition of oak wood varies from species to species and approximately contains 50% carbon, 42% oxygen, 6% hydrogen, 1% nitrogen and 1% other elements mainly Ca, Mg, K, Na, Fe, and Mn.
  • oak leaves contain almost similar or less percentage of the elements previously said especially potassium.
  • the hidden properties of oak fmit must be explored in order to understand the importance of the oak fmit as natural herbs.
  • Potassium plays an important role for proper growth of the plant. It considered second only to nitrogen, when it comes to nutrient needed by the plants. Further, it is reported that Potassium supports blood pressure, cardiovascular health, bone strength, and muscle strength.
  • the potassium is present in form of K + ions in the plants/plant fruits. So, when the K + moiety of the oak fruit interacts with the selective solvents such as ethanol, formation of the potassium ethoxide takes place which is acting as strong base.
  • the strong base abstracts hydrogen ions from the cellulosic part of the plant and thereby acts as a driving force for the formation of the graphitic moiety by developing conjugation within the system.
  • Graphene oxide is an oxygenated derivative of graphene.
  • GO is an amphiphilic molecule having the structural network of interconnected random distribution of aliphatic and aromatic regions. This structural network makes them superior material for great potential applications in various fields of research such as electronics, photocatalysis, solar cells, supercapacitors, medicine, sensors and biosensors.
  • GO is mainly prepared by chemically exfoliating graphite, and by Hummer's method in which toxic gases such as dinitrogen tetroxide, nitrogen dioxide evolved which causes pulmonary edema.
  • Graphene becomes the focus that recent field of nanometer material technology is paid close attention to because of its superpower mechanical strength, the excellent characteristics such as conduction, thermal conduction characteristic, chemical stability.
  • the method of chemical reduction of graphene oxide is the current common method preparing single-layer graphene on a large scale. These class methods and the method such as mechanically peel, electrochemical deposition have economy, efficiently, are easy to the advantages such as large-scale production, have very wide potential application foreground.
  • In the method for current chemical reduction of graphene oxide extensively adopt poisonous, expensive reductive agent, as hydrazine hydrate, dimethylhydrazine, Ursol D, Dopamine HCL etc. Explore simple, economical, effectively, the reducing process of environmental protection and method have very important theory significance and realistic meaning. Chemical exfoliation of graphene is one of the dilemmas and evolution of toxic gases is one of the main drawbacks which cause some health issues.
  • the present invention aims at providing a facile, robust simple, cost effective, green and eco-friendly approach to synthesize potassium doped graphene oxide (K-doped GOs) for bio-imaging applications, using an environmentally non-hazardous, cost effective and greener synthetic pathway from agriculture waste (oak fruit).
  • K-doped GOs potassium doped graphene oxide
  • the present disclosure aims at providing a natural source of potassium from the oak fruit in order to support human beings. Particularly, performing graphitization of the cellulosic part of the oak fmit converting it into Graphenenanosheets. Also, the present invention shows 7% potassium in the oak fmit. [0012]
  • the invention focusses on direct application of bio imaging with the presence of natural occurring metals and the other form the invention relates simple and single step procedure for the mass scale production of graphene for biomedical application.
  • the present invention objects the production of high-quality mass production of potassium doped graphene from oak-seed.
  • This invention rectifies the qualitative use of K-doped graphene for bio-imaging applications with eco-friendly approach.
  • the invention represents the K-doped graphene as highly soluble material in polar and other physiological solution in the drug delivery application.
  • Various embodiments of the present invention disclose a hydro-solvo-thermal graphene oxide synthesis method to obtain potassium-doped graphene oxide for bio-sensing and bio-imaging of one or more naturally occurring source.
  • the method includes the steps of collecting and preparing Quercus ilex fruit for the hydro-solvo-thermal graphene oxide synthesis, solvothermal grinding of the Quercus ilex fruit in a solvent mixture to obtain a crushed extract paste, synthesizing the crushed extract paste to obtain a brown solid residue, coefficient separating by centrifuging the brown residue to obtain the uniform brownish solution, nano filtering the uniform brownish solution using a nylon filter paper to obtain a clear brownish solution and drying the clear brownish solution in an oven to evaporate solvent mixture to obtain a dried brown solid.
  • the dried brown solid is potassium-doped graphene oxide.
  • heating of the crushed extract paste is performed at a temperature 120°C for 4 hours in an oven. Furthermore, heating initiates growth of multiple graphitic
  • the solvent mixture further comprises ethanol and double distilled waterjs Ep jln
  • the collecting and preparing further includes steps of mechanically separating outer shell and inner white part of the plurality of Quercus ilex fruit, cleaning the inner white part with double distilled water, removing outer layers to remove a plurality of solid impurities from the plurality of Quercus ilex fruit and protecting the outer layers of the plurality of Quercus ilex fruit in a protected medium to maintain the purity of the outer layers.
  • the solvothermal grinding further includes crushing a predefined quantity the protected outer layers of the plurality of Quercus ilex fruit using mortar to form a crushed extract, grinding the white part of the plurality of Quercus ilex fruit by a nano ball-mill machine, mixing a predefined quantity of the white part mixed with a predefined volume of the solvents in a molar ratio of 1 : 1 to obtain a mixture and heating the mixture in an oven at a temperature of 120 °C for 4 hours to obtain a brown coloured solid residue.
  • coefficient separating step further includes crushing the brown residue in the mortar to form a crushed brown solid residue, dispensing the crushed brown solid residue in a predefined volume of double distilled water using magnetic stirrer for 30 minutes and centrifuging the dispensed crushed brown solid residue in a centrifuge.
  • the centrifuge has a speed of 7000 rotations per minute (rpm) for 15 minutes at room temperature to obtain the uniform brownish solution.
  • the nano filtering is a particle filtering method.
  • nano filtering uses a 0.2 um nylon filter paper to obtain the clear brownish solution. Moreover, successive filtration is performed until a clear brownish solution is obtained.
  • the potassium-doped graphene oxide is characterized for bio-sensing and bio-imaging of at least one naturally occurring source. Particularly, the characterization confirms that the dried brown solid material is as K-doped GO by various characterization techniques including RAMAN, FT-IR, TEM and alike techniques.
  • the drying is carried out in an oven at a temperature of drying 100 °C.
  • the weight of the potassium-doped graphene oxide is 4 mg.
  • the concentration of potassium-doped graphene oxide in a solution is 4 mg/mL.
  • the natural occurring source is a natural occurring source metal.
  • FIG. 1A is a graphical representation illustrating a Raman spectra of graphene oxide nanosheets in accordance with one or more embodiments of the present invention
  • Fig. IB is a graphical representation illustrating a Fourier transform infrared spectra of potassium doped graphene oxide in accordance with one or more embodiments of the present invention
  • FIG. 1C is a pictorial snapshot illustrating a TEM image of graphene oxide nanosheets in accordance with one or more embodiments of the present invention
  • Fig. ID is a pictorial snapshot illustrating an EDX image of graphene oxide nanosheets in accordance with one or more embodiments of the present invention
  • Fig. 2A is a graphical representation illustrating a full XPS spectra of K-doped GO in accordance with one or more embodiments of the present invention
  • Fig. 2B is a graphical representation illustrating an XPS spectra showing the binding energy of potassium in accordance with one or more embodiments of the present invention
  • Fig. 2C is a graphical representation illustrating fluorescence emission response of K-doped GO at different excitations in accordance with one or more embodiments of the present invention
  • Fig. 2D is a graphical representation illustrating an absorption spectra and emission spectra in accordance with one or more embodiments of the present invention
  • FIG. 3 is a tabular representation illustrating different cases of pristine in accordance with one or more embodiments of the present invention.
  • Fig. 4 A is a pictorial snapshot illustrating microscopic images illustrating biocompatibility and bio-imaging of K-doped GO in non-tumorigenic ovarian epithelial IOSE in accordance with one or more embodiments of the present invention
  • Fig. 4 B is a graphical snapshot illustrating cell viability MTT assay of K-doped GO in accordance with one or more embodiments of the present invention
  • Fig. 4 C is a flow cytometry data snapshot illustrating the live and dead cell populations after staining in accordance with one or more embodiments of the present invention
  • Fig. 4D is a pictorial snapshot illustrating confocal microscopic images of cells using K- doped GO as fluorescent probe in accordance with one or more embodiments of the present invention
  • Fig. 5 is a pictorial snapshot illustrating a K- doped GOs in a normal light and UV in light of 365 nm in accordance with one or more embodiments of the present invention
  • Fig. 6 is agraphical snapshot illustrating XRD of K-doped graphene oxide in accordance with one or more embodiments of the present invention.
  • Fog.7 is a graphical snapshot illustrating TGA of K-doped graphene oxide in accordance with one or more embodiments of the present invention.
  • Fig. 8 A is a graphical snapshot illustrating XPS Cls spectra of K-doped graphene in accordance with one or more embodiments of the present invention
  • Fig. 8B is a graphical snapshot illustrating Ols spectra of K-doped graphene in accordance with one or more embodiments of the present invention
  • Fig.9 is a flow chart illustrating a hydro-solvo-thermal graphene oxide synthesis method to obtain potassium-doped graphene oxide in in accordance with one or more embodiments of the present invention
  • Fig. 10 is pictorial snapshot illustrating the hydro-solvo-thermal graphene oxide synthesis method to obtain potassium-doped graphene oxide in in accordance with one or more embodiments of the present invention.
  • FIG. 1 to FIG. 10 Various embodiments of the present invention relate to hydro-solvo-thermal graphene oxide synthesis method to obtain potassium-doped graphene oxide. Moreover, the principles of the present invention and their advantages are best understood by referring to FIG. 1 to FIG. 10.
  • references within the specification to “one embodiment,” “an embodiment,” “embodiments,” or “one or more embodiments” are intended to indicate that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure.
  • the appearance of such phrases in various places within the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.
  • various features are described which may be exhibited by some embodiments and not by others.
  • various requirements are described which may be requirements for some embodiments but no other embodiments.
  • Fig. 1A is a graphical representation illustrating a Raman spectra of graphene oxide nanosheets in accordance with one or more embodiments of the present invention.
  • the Raman spectrum of K-doped GOs illustrates two signature peaks for carbon at 1312cm -1 and 1531cm -1 corresponds to D and G bands, respectively.
  • the D and G bands correspond to the disordered structure in crystalline of sp2 cluster and the in-plane stretching vibration mode E2g of single-crystal graphite.
  • the synthesis of the K- doped graphene oxide is done by solvothermal process.
  • the growth of the sp2 hybridized carbon atoms from sp3 hybridized carbon atoms of the white part of the oak fruit (majorly contains cellulosic sp3 carbon atoms) is initiated within the system as the temperature reaches the maximum of boiling temperature of the solvent systems taken for the process.
  • the solvothermal route leads the carbonization of the cellulosic carbon atoms by developing sp2 bonded carbon atoms as the intermediate, which in turns of stabilizing concerns, converted into sheet like structure of graphitic form of carbon.
  • the Raman spectroscopy performed confirms the synthesis of graphene and assess the quality.
  • Fig. IB is a graphical representation illustrating a Fourier transform infrared spectra of potassium doped graphene oxide in accordance with one or more embodiments of the present invention.
  • the Fourier transform infrared spectra is performed to identify the presence of different functional groups on the surface of graphene oxide nanosheets.
  • Fig. 1C is a pictorial snapshot illustrating a TEM image of graphene oxide nanosheets in accordance with one or more embodiments of the present invention.
  • the TEM image of K-doped GOs shows uniform size of synthesized graphenenanosheets.
  • Fig. ID is a pictorial snapshot illustrating an EDX image of graphene oxide nanosheets in accordance with one or more embodiments of the present invention.
  • XPS X-ray photoelectron spectroscopy
  • Fig. 2A is a graphical representation illustrating a full XPS spectra of K-doped GO in accordance with one or more embodiments of the present invention.
  • the full XPS spectra of K-doped GOs has three peaks at 284.4, 291.8 and 532eV attributed to Cls, K2P and Ols respectively.
  • Fig. 2B is a graphical representation illustrating an XPS spectra showing the binding energy of potassium in accordance with one or more embodiments of the present invention
  • Fig. 2C is a graphical representation illustrating fluorescence emission response of K-doped GO at different excitations in accordance with one or more embodiments of the present invention
  • the concentration is 0.02 mg/mL in Double distilled water inset shows normalized fluorescence spectra.
  • the excitation dependent property of synthesized K-doped GO, scans ranging from 330 to 5 lOnm (20nm l excinterval) are collected with its emission response.
  • the results plotted in Fig. 2C indicate that the emission of K-doped GOs is excitation dependent.
  • the normalized fluorescence spectra plotted in the inset shows clear red shift of fluorescence intensity with the excitation wavelength of K-doped GOs.
  • Fig. 2D is a graphical representation illustrating an absorption spectra and emission spectra in accordance with one or more embodiments of the present invention.
  • the absorption spectra and emission spectra has an excitation at 370 nm of K-doped GO.
  • blue fluorescence is observed when exposed to UV light of 365 nm.
  • the two different peak satellites corresponding to K2P3/2 at 292.3 and K2P1/2 at 294.8eV [34] are obtained.
  • the XPS data validates the presence of functional groups (carbonyl, hydroxyl and epoxy groups) on graphenenanosheets.
  • the K-doped GO solution shows strong absorption in the wavelength range 240-380 nm with maximum at 270nm due to p-p* transition with a black dark line.
  • the wide absorption range is a result of diverse size of K-doped GOs dispersed in water and K-doped GO shows emission maxima at 461nm on excitation at 370 nm.
  • Fig. 3 is a tabular representation illustrating binding energy (EB) for each of the adsorption cases of pristine in accordance with one or more embodiments of the present invention.
  • the binding energy for each adsorption case is denoted in the respective images.
  • the balls indicate carbon and potassium atoms.
  • the semi-empirical Grimme DFT-D2 correction has been used to define the Vander Waals interaction between potassium and graphene sheet.
  • the valence electrons are described by localized pseudo atomic orbitals with double zeta polarized basis set, and a large density mesh cut off of 130 Hartree considered for accuracy of calculations.
  • the geometry relaxations of 4*4 hexagonal super cells have been performed using 12*12*1 Monkhorst-Pack grid of k-points.
  • the cases 1-3 of the table illustrates a top view and a side view of pristine, case-4 illustrates defected pristine, case-5 illustrates bilayer graphene on adsorption of Potassium (K).
  • the binding energy of potassium adsorption on the carbon atom site (case-1), bridge site (case-2) and hollow site (case-3) of pristine graphene are 1.30eV, 1.3 leV and 1.37eV, respectively, inferring the relatively strong chemisorption of potassium towards the hollow site of pristine graphene in comparison to carbon and bride sites.
  • the binding energy of potassium adsorption at the vacancy site of defected graphene (case-4) is the highest (2.4 leV) among all the five adsorption cases studied.
  • the trigonal pyramidal shape of potassium at the vacancy defect site indicates possible sp3 hybridization undergone by the potassium atom.
  • the synthesized GO contains multi-layered structure; we have also studied the intercalation of potassium into bilayer graphene (case-5).
  • the binding energy of potassium intercalation into bilayer graphene is the least (0.44eV) of all the five cases.
  • the intercalation has resulted in increased inter-layer distance of bilayer graphene from 3.32 ⁇ to 4.90A.
  • the obtained results show that the potassium atoms are most likely chemisorbed on the vacancy defect sites and hollow sites (hexagonal rings) of the synthesized GO, owing to their high binding energies.
  • the probability of potassium intercalation into the GO layers is very low as evidenced from the very low binding energy and the intercalation induced structural distortion.
  • Fig. 4 A is a pictorial snapshot illustrating microscopic images illustrating biocompatibility and bio-imaging of K-doped GO in non-tumorigenic ovarian epithelial IOSE-364 cells in accordance with one or more embodiments of the present invention.
  • the biological endpoints used in cell viability testing include morphological assessment using phase contrast microscopic images and cell viability and proliferation assays such as MTT (dimethylthiazol-diphenyltetrazolium bromide), sulforhodamine B (SRB) and others.
  • MTT dimethylthiazol-diphenyltetrazolium bromide
  • SRB sulforhodamine B
  • the cells are stained with Sulphorhodamine B after treatment with different concentrations of K-doped GO for 24 h. Therefore, at first to determine the cytotoxic effect of those compounds, we performed Sulphorhodamine B colorimetric assay using IOSE-364 cells are evaluated by measuring the half maximal inhibitory concentration (IC50) in comparison with the untreated control as described previously. The cytotoxic effect was also assessed by flow cytometry with staining of Propidium iodide.
  • the biocompatibility study of the synthesized K-doped GO compounds is performed using non tumorigenic ovarian epithelial IOSE-364 cells.
  • 5000 cells are seeded into each well of 96 well microtiter plates and exposed to various indicated concentrations of K-doped GO for 24 hours.
  • cells are fixed in situ by the gentle addition of 50pL of cold 30% (w/v) TCA (final concentration, 10% TCA) and incubated for 30 minutes at 4°C, followed by stained with sulforhodamine B (SRB) solution at 0.4% (w/v) in 1% acetic acid, after which the excess dye is removed by washing with 1% acetic acid.
  • SRB sulforhodamine B
  • the protein bound dye is subsequently solubilized in 10 mMTris base for OD determination at 565nm using Spectrophotometer.
  • Fig. 4 B is a graphical snapshot illustrating cell viability MTT assay of K-doped GO in accordance with one or more embodiments of the present invention.
  • the cell viability MTT assay is performed at different indicated concentrations using IOSE-364 cells for 24 hours and 48 hours.
  • the results reveal that the cell viability is>90% at a concentration of 30pg/mL and IC value of >50pg/mL.
  • the cells at a concentration of 5000 cells/well are seeded in 96 well micro titer plates and exposed to various concentrations (0, 10, 20, 30, 40 and 50pg/mL) of K-doped GO. Moreover, a relative cell survival percentage is determined using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide) assay after treatment for 24 hours and 48hours. The MTT (5mg/mL) is added into each well and incubated for 4 hours at 37°C. The formazan crystals formed are dissolved in DMSO. The intensity of colored formazan formed is determined by measuring the absorbance at 570nm using ELIS Areader.
  • MTT 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide
  • Fig. 4 C is a flow cytometry data snapshot illustrating the live and dead cell populations after staining in accordance with one or more embodiments of the present invention.
  • Fig. 4D is a pictorial snapshot illustrating confocal microscopic images of cells using K- doped GO as fluorescent probe in accordance with one or more embodiments of the present invention.
  • the stable blue fluorescence properties for the water-soluble potassium-doped Graphene Oxides when the non-tumorigenic ovarian epithelial IOSE-364 cells are incubated with K-doped GOs for 4 hours.
  • the epithelial IOSE-364 cells are washed, and images are taken using fluorescence microscope.
  • showing a good biocompatibility, intracellular localization, and strong PL properties of the synthesized K-doped GOs demonstrated to be an excellent bio-imaging agent holding great promise in analytical and biological fields.
  • Fig. 5 is a pictorial snapshot illustrating a K- doped GOs in a normal light and UV in light of 365 nm in accordance with one or more embodiments of the present invention.
  • the UV- visible electronic absorption spectra measurements are carried out in Agilent Cary 100-UV-visible Spectrophotometer.
  • the fluorescence emission spectra are measured using Varian Cary Eclipse spectrofluorometer. A strong blue fluorescence is observed at UV light of 365nm.
  • the maximum assay of potassium in the graphene oxide sheets plays significant role for the human beings, as demonstrated by the one of the applications of the K-GO in bio imaging of the cancerous cells. Further, other studies showed that the presence of potassium in graphene oxide showed the high superconductivity behavior which could reveal another important part of the synthesized material in near future.
  • the Raman (Research India, RIRM-LP1519; with 532nm excitation), FT-IR (Perkin Elmer), X-ray photoelectron spectroscopy (XPS) (Physical Electronics make PHI 5000 Versa Probe III spectrometer using A1 Ka radiation (1486.6eV)), TEM (JEOL, JEM 2100 microscope), and TGA (PerkinElmer, TGA 4000 thermal analyzer) are performed to investigate the chemical composition, and morphology of the prepared nano conjugates.
  • XRD X-ray diffraction
  • Fig. 6 is agraphical snapshot illustrating XRD of K-doped graphene oxide in accordance with one or more embodiments of the present invention.
  • the thickness and number of graphene layers are calculated by XRD wherein the number of layers of K-doped GO sheets obtained from dividing the crystal size (C) by the interlayer distance (d) added to the thickness of one graphene sheet (0.1nm). The crystal size (C) was calculated with the help of Scherrer equation.
  • the interlayer distances (d) in the graphene were estimated using Bragg's Law.
  • the inter planar distance is 0.65 nm. According to the XRD data, there are about four graphene layers in the K-doped GO.
  • Fog.7 is a graphical snapshot illustrating TGA of K-doped graphene oxide in accordance with one or more embodiments of the present invention.
  • thermo-gravimetric analysis TGA
  • weight loss of graphenenanosheets took place in two stages i.e. at 180°C to 325°C and 400°C to 685°C.
  • the first stage weight loss from 180°C to 325°C shows the removal of chemisorbed water molecules and oxygen associated functional groups in the graphenenanosheets.
  • the second stage weight loss (400°C to 685°C) demonstrates notable evidence about the oxidation of carbon skeleton of graphenenanosheets.
  • a 2.10% residual weight at 675°C indicated the presence of higher number of functional groups at graphenenanosheets.
  • Fig. 8B is a graphical snapshot illustrating Ols spectra of K-doped graphene in accordance with one or more embodiments of the present invention.
  • Fig.9 is a flow chart illustrating a hydro-solvo-thermal graphene oxide synthesis method to obtain potassium-doped graphene oxide in in accordance with one or more embodiments of the present invention.
  • the one step hydro-solvo-thermal graphene oxide synthesis method 900 to obtain potassium-doped graphene oxide for bio-sensing and bio-imaging of one or more natural occurring source starts at step 905.
  • the Quercus ilex fruit is collected and prepared by mechanically separating outer shell and inner white part of the plurality of Quercus ilex fruit, cleaning the inner white part with double distilled water, removing outer layers to remove a plurality of solid impurities from the plurality of Quercus ilex fruit. Moreover, protecting the outer layers of Quercus ilex fruit in a protected medium to maintain the purity of the outer layers.
  • step 905 proceeds to step 910.
  • the prepared Quercus ilex fruit is subjected to solvothermal grinding using a solvent mixture to obtain a crushed extract paste.
  • the solvent mixture further comprises ethanol and double distilled water.
  • the solvothermal grinding further includes crushing a predefined quantity the protected outer layers of the plurality of Quercus ilex fruit using mortar to form a crushed extract, grinding the white part of Quercus ilex fruit by a nano ball-mill machine. Furthermore, mixing a predefined quantity (4grams) of the white part mixed with a predefined volume (20mL) of the each solvent in a molar ratio of 1 : 1 to obtain a mixture and heating the mixture in an oven at a temperature of 120 °C for 4 hours to obtain a brown coloured solid residue. The crushed extract paste is heated at a temperature of 120°C for 4 hours in an oven. Subsequently, heating initiates growth of multiple graphitic sheets.
  • step 910 proceeds to step 920.
  • step 915 the brown residue is subjected to coefficient separating.
  • the coefficient separating includes crushing the brown residue in the mortar to form a crushed brown solid residue, dispensing the crushed brown solid residue in a predefined volume of double distilled water using magnetic stirrer for 30 minutes. Moreover, centrifuging the dispensed crushed brown solid residue in a centrifuge having 7000 rotations per minute (rpm) for 15 minutes at room temperature to obtain said uniform brownish solution.
  • the step 915 proceeds to step 920.
  • the uniform brownish solution undergoes nanofiltration to obtain a clear brownish solution.
  • the nanofiltration is a particle filtering method.
  • nanofiltration uses a 0.2 um nylon filter paper to obtain the clear brownish solution.
  • the brownish solution is subjected to successive filtration to obtain a clear brownish solution.
  • step 920 proceeds to step 925.
  • the clear brownish solution is dried in an oven to evaporate solvent mixture to obtain a dried brown solid.
  • the dried brown solid is potassium-doped graphene oxide.
  • the drying temperature is chosen as 100 °C, to allow the different solvents to evaporate and to stabilize the resultant products without finding its non- reduced form.
  • step 925 proceeds to step 930.
  • the potassium-doped graphene oxide obtained is characterized for bio-sensing and bio-imaging of at least one naturally occurring source. Particularly, the characterization confirms that the dried brown solid material is as K-doped GO by various characterization techniques including RAMAN, FT-IR, TEM and alike techniques.
  • the weight of the potassium-doped graphene oxide is 4 mg.
  • the concentration of potassium-doped graphene oxide in a solution is 4 mg/mL.
  • the natural occurring source is a natural occurring source metal.
  • Fig. 10 is pictorial snapshot illustrating the hydro-solvo-thermal graphene oxide synthesis method to obtain potassium-doped graphene oxide in in accordance with one or more embodiments of the present invention.
  • FIG. 11 is a pictorial snapshot illustrating use of the graphene oxide as a sensor for detection of iron in water, in accordance with yet another embodiment of present invention.
  • Fig. 11 illustrates triple distilled water with 10].il K-doped graphene oxide (left) and lmM Fe 3+ in triple distilled water with 10m1 K-doped graphene oxide.
  • the potassium doped graphene oxide detects the presence of iron selectively in water samples and plays a great role in field of sensor to detect heavy metal i.e. ion present in water samples.
  • the brownish solution of synthesized K-doped GO shows bright blue fluorescence under UV light and exhibits the selective quenching of fluorescence in presence of iron.
  • Fig. 12 is a graphical snapshot illustrating PL emission spectra of K-doped GO under different excitation wavelength from 330 to 490 nm in accordance with yet another embodiment of present invention.
  • the synthesized K-doped GO represent the excitation dependent emission behavior and shows emission maxima at 430nm when excited at 330nm
  • the significant quenching of fluorescence intensity in case of iron indicates its selectivity towards the detection of iron in presence of other metals which are Li + , Na + , Mg 2+ , Al 3+ , K + , Ca 2+ , Mn 2+ , Fe 3+ , Co 2+ , Ni 2+ , Zn 2+ , Ag + , Cd 2+ , Cs + and Ba 2+ .
  • Fig. 13 is a graphical snapshot illustrating metal stability of K-doped GO in the presence of different metal ions in accordance with yet another embodiment of present invention.
  • the selectivity studies are carried out using fluorescence spectrophotometer which reveals that our material i.e. K-doped GO can selectively detect Fe (III) ions.
  • the fluorescence properties of K-doped GO was quenched in presence of Fe 3+ ion while with the other metal ions quenching is almost negligible or there is no quenching due to the exceptional coordination between Fe 3+ ion and hydroxyl group of K-doped GO.
  • Fig. 14 is a graphical snapshot illustrating interference study of K-doped GO in the presence of different metal ions in accordance with yet another embodiment of present invention.
  • the value of 1-F/F 0 is zero and for Li + , Na + , Mg 2+ , Al 3+ , K + , Ca 2+ , Mn 2+ , Fe 3+ , Co 2+ , Ni 2+ , Zn 2+ , Ag + , Cd 2+ , Cs + , Ba 2+ the values of 1-F/F 0 are 0.07,0.07, 0.1, 0.1, 0.06, 0.07, 0.18, 0.88, 0.14, 0.28, 0.1,0.1, 0.1, 0.14, 0.07 respectively.
  • Fig. 15 is a graphical snapshot illustrating Plot for limit of detection in accordance with yet another embodiment of present invention.
  • the fluorescence quenching effect of Fe3+ is performed to explore the sensitivity of K-doped GO toward Fe3+ ion concentration.
  • the fluorescence intensity decreased with increasing Fe3+ concentration.
  • the fluorescence quenching efficiency is described by the Stem-Volmer plot with a perfect linear behavior (the linear correlation coefficient was (0.987) in the range of Fe3+ concentrations from 1X10-7 M to 10X10-7 M.
  • the detection limit is as low as 0.345X10-7M (34.5 nM) using the formula 3o/m, where s was the standard deviation of blank sample signal and m was the slope of the linear fit.
  • various embodiments of the present invention illustrate a method for the synthesis of a potassium-doped graphene oxide from a Quercus ilex fruit for bio-sensing and bio-imaging.
  • the advantage of the present invention is that the present method a facile, eco-friendly and cost effective hydrothermal route for the synthesis of potassium doped graphene oxide (K-doped GO) from agricultural waste i.e. Quercus ilex Fruit by naturally preparing potassium doped blue graphene oxide sheets (PDGOs) by thermal treatment of the waste part of Quercus ilex (oak) fruit.
  • the prepared K-doped GO sheets are highly water-soluble and emitted excellent bright blue fluorescence under UV-light.
  • the GO obtained has excellent bio-imaging with excellent natural doping of potassium.
  • This invention is a new insight for the various bio imaging and bio-sensing industries not only due to its ecofriendly approach but also due to the fine qualitative productions of naturally potassium doped graphene.
  • the ecofriendly K- doped graphene can act as the valuable agent for the treatment of various vital disease such as cancer.
  • the results are in support of cancerous cell detection to cancerous cell destruction which is a spanking tool for the development of new drugs of cancer like vital disease in various bio-medical industries.

Landscapes

  • Health & Medical Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Medicinal Chemistry (AREA)
  • Pharmacology & Pharmacy (AREA)
  • Epidemiology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Carbon And Carbon Compounds (AREA)

Abstract

The present invention relates to a hydro-solvo -thermal graphene oxide synthesis method to obtain potassium-doped graphene oxide for bio-sensing and bio-imaging of natural occurring source. The method includes solvothermal grinding of the Quercus ilex fruit in a solvent mixture to obtain a crushed extract paste, synthesizing the crushed extract paste to obtain a brown solid residue, coefficient separating of the brown residue to obtain the uniform brownish solution, nano filtering to obtain a clear brownish solution and drying the clear brownish solution to obtain a dried brown solid of potassium-doped graphene oxide.

Description

H YD RO-SOl /VO-THERMAL GRAPHENE OXIDE SYNTHESIS METHOD Field of the Invention
[0001] The present invention relates to the technical field of carbon structure production and, in particular, to a method for synthesis of graphene oxide to obtain potassium-doped graphene oxide for bio-sensing and bio-imaging.
BACKGROUND OF THE INVENTION
[0002] Oak fruit (Quercus ilex) is found in higher region of Himalaya in India. Generally, it has been noticed that in winter season monkeys and apes prefer to eat oak fruit very passionately. As a fact till present time the oak fmit is treated as agricultural waste for the consumption by animals and is overlooked by human beings. Particularly, the chemical composition of oak wood varies from species to species and approximately contains 50% carbon, 42% oxygen, 6% hydrogen, 1% nitrogen and 1% other elements mainly Ca, Mg, K, Na, Fe, and Mn. While oak leaves contain almost similar or less percentage of the elements previously said especially potassium. However, the hidden properties of oak fmit must be explored in order to understand the importance of the oak fmit as natural herbs. [0003] It is reported that Potassium plays an important role for proper growth of the plant. It considered second only to nitrogen, when it comes to nutrient needed by the plants. Further, it is reported that Potassium supports blood pressure, cardiovascular health, bone strength, and muscle strength. The potassium is present in form of K+ ions in the plants/plant fruits. So, when the K+ moiety of the oak fruit interacts with the selective solvents such as ethanol, formation of the potassium ethoxide takes place which is acting as strong base. The strong base abstracts hydrogen ions from the cellulosic part of the plant and thereby acts as a driving force for the formation of the graphitic moiety by developing conjugation within the system.
[0004] Graphene oxide (GO), is an oxygenated derivative of graphene. In particular, is an amphiphilic molecule having the structural network of interconnected random distribution of aliphatic and aromatic regions. This structural network makes them superior material for great potential applications in various fields of research such as electronics, photocatalysis, solar cells, supercapacitors, medicine, sensors and biosensors. Presently GO is mainly prepared by chemically exfoliating graphite, and by Hummer's method in which toxic gases such as dinitrogen tetroxide, nitrogen dioxide evolved which causes pulmonary edema.
[0005] The introduction of natural and cost-effective greener methods for the synthesis of graphene and their counterparts has attracted tremendous attention. Although several chemical methods have been discussed and used by the researchers to make large quantity of GQDs and GO sheets, yet very little effort has been made so far to synthesize environmentally non-hazardous photoluminescent GO materials. Potassium has been considered as a hetero dopant owing to its ability to enhance optical properties of nanomaterials. [0006] Graphene (graphene) becomes the focus that recent field of nanometer material technology is paid close attention to because of its superpower mechanical strength, the excellent characteristics such as conduction, thermal conduction characteristic, chemical stability.The method of chemical reduction of graphene oxide is the current common method preparing single-layer graphene on a large scale.These class methods and the method such as mechanically peel, electrochemical deposition have economy, efficiently, are easy to the advantages such as large-scale production, have very wide potential application foreground.In the method for current chemical reduction of graphene oxide, extensively adopt poisonous, expensive reductive agent, as hydrazine hydrate, dimethylhydrazine, Ursol D, Dopamine HCL etc. Explore simple, economical, effectively, the reducing process of environmental protection and method have very important theory significance and realistic meaning. Chemical exfoliation of graphene is one of the dilemmas and evolution of toxic gases is one of the main drawbacks which cause some health issues.
[0007] Chinese Patent CN102219211B titled “Method for reducing and decorating graphene oxide by plant polyphenol and derivant thereof’ focusses on a method for plant polyphenol and derivative reduction and modification graphene oxide.
[0008] Chinese Patent CN106279580A titled “A kind of poly carboxylic acid modified graphene oxide complex and preparation method and applicatiori’focusses on polycarboxylic acids-modified graphene oxide and be combined Thing and preparation method and application.
[0009] Although there are several processes available for deposition of potassium on the surface of carbon nanomaterials, they require vacuum systems, high-temperature heat treatment, and long processing times, But none of these methods has reported the natural doping of the potassium for bioimaging applications. Fortunately, oak fruits, found in the high altitude of the Himalayan region has found as a rich source of potassium with various medicinal properties. Since Oak fruit ( Quercus ilex) is not utilized by humans despite being rich in nutrients diverts the new era research to focus on oaks. [0010] Thereby, the hidden properties of the natural source of potassium in the form of oak fruit must be explored in order to understand the importance of the natural herbs. In order to explore the charming properties of the naturally rich potassium doped oak fruits as a value added product, the present invention aims at providing a facile, robust simple, cost effective, green and eco-friendly approach to synthesize potassium doped graphene oxide (K-doped GOs) for bio-imaging applications, using an environmentally non-hazardous, cost effective and greener synthetic pathway from agriculture waste (oak fruit).
[0011] Therefore, to overcome the said drawbacks the present disclosure aims at providing a natural source of potassium from the oak fruit in order to support human beings. Particularly, performing graphitization of the cellulosic part of the oak fmit converting it into Graphenenanosheets. Also, the present invention shows 7% potassium in the oak fmit. [0012] The invention focusses on direct application of bio imaging with the presence of natural occurring metals and the other form the invention relates simple and single step procedure for the mass scale production of graphene for biomedical application.
[0013] The present invention objects the production of high-quality mass production of potassium doped graphene from oak-seed. This invention rectifies the qualitative use of K-doped graphene for bio-imaging applications with eco-friendly approach. While the invention represents the K-doped graphene as highly soluble material in polar and other physiological solution in the drug delivery application.
SUMMARY OF THE INVENTION
[0014] This summary is provided to introduce a selection of concepts in a simple manner, which is further described in the detailed description of the invention. This summary is neither intended to identify key or essential inventive concepts of the subject matter nor to determine the scope of the invention.
[0015] Various embodiments of the present invention disclose a hydro-solvo-thermal graphene oxide synthesis method to obtain potassium-doped graphene oxide for bio-sensing and bio-imaging of one or more naturally occurring source. The method includes the steps of collecting and preparing Quercus ilex fruit for the hydro-solvo-thermal graphene oxide synthesis, solvothermal grinding of the Quercus ilex fruit in a solvent mixture to obtain a crushed extract paste, synthesizing the crushed extract paste to obtain a brown solid residue, coefficient separating by centrifuging the brown residue to obtain the uniform brownish solution, nano filtering the uniform brownish solution using a nylon filter paper to obtain a clear brownish solution and drying the clear brownish solution in an oven to evaporate solvent mixture to obtain a dried brown solid. In particular, the dried brown solid is potassium-doped graphene oxide. Moreover, heating of the crushed extract paste is performed at a temperature 120°C for 4 hours in an oven. Furthermore, heating initiates growth of multiple graphitic sheets.
[0016] In accordance with one or more embodiments of the present invention, the solvent mixture further comprises ethanol and double distilled waterjsEpjln accordance with one or more embodiments of the present invention, the collecting and preparing further includes steps of mechanically separating outer shell and inner white part of the plurality of Quercus ilex fruit, cleaning the inner white part with double distilled water, removing outer layers to remove a plurality of solid impurities from the plurality of Quercus ilex fruit and protecting the outer layers of the plurality of Quercus ilex fruit in a protected medium to maintain the purity of the outer layers.
[0017] In accordance with one or more embodiments of the present invention, the solvothermal grinding further includes crushing a predefined quantity the protected outer layers of the plurality of Quercus ilex fruit using mortar to form a crushed extract, grinding the white part of the plurality of Quercus ilex fruit by a nano ball-mill machine, mixing a predefined quantity of the white part mixed with a predefined volume of the solvents in a molar ratio of 1 : 1 to obtain a mixture and heating the mixture in an oven at a temperature of 120 °C for 4 hours to obtain a brown coloured solid residue. [0018] In accordance with one or more embodiments of the present invention, wherein coefficient separating step further includes crushing the brown residue in the mortar to form a crushed brown solid residue, dispensing the crushed brown solid residue in a predefined volume of double distilled water using magnetic stirrer for 30 minutes and centrifuging the dispensed crushed brown solid residue in a centrifuge. In particular, the centrifuge has a speed of 7000 rotations per minute (rpm) for 15 minutes at room temperature to obtain the uniform brownish solution.
[0019] In accordance with one or more embodiments of the present invention, the nano filtering is a particle filtering method. In particular, nano filtering uses a 0.2 um nylon filter paper to obtain the clear brownish solution. Moreover, successive filtration is performed until a clear brownish solution is obtained.
[0020] In accordance with one or more embodiments of the present invention, the potassium-doped graphene oxide is characterized for bio-sensing and bio-imaging of at least one naturally occurring source. Particularly, the characterization confirms that the dried brown solid material is as K-doped GO by various characterization techniques including RAMAN, FT-IR, TEM and alike techniques. [0021] In accordance with one or more embodiments of the present invention, the drying is carried out in an oven at a temperature of drying 100 °C.
[0022] In accordance with one or more embodiments of the present invention, the weight of the potassium-doped graphene oxide is 4 mg.
[0023] In accordance with one or more embodiments of the present invention, the concentration of potassium-doped graphene oxide in a solution is 4 mg/mL.
[0024] In accordance with one or more embodiments of the present invention, the natural occurring source is a natural occurring source metal.
DESCRIPTION OF THE DRAWINGS
[0025] So that the manner in which the above recited features of the present invention is to be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.
[0026] A better understanding of the present invention can be obtained when the following detailed description of the preferred embodiment is considered in conjunction with the following drawings, in which: [0027] Fig. 1A is a graphical representation illustrating a Raman spectra of graphene oxide nanosheets in accordance with one or more embodiments of the present invention;
[0028] Fig. IB is a graphical representation illustrating a Fourier transform infrared spectra of potassium doped graphene oxide in accordance with one or more embodiments of the present invention;
[0029] Fig. 1C is a pictorial snapshot illustrating a TEM image of graphene oxide nanosheets in accordance with one or more embodiments of the present invention;
[0030] Fig. ID is a pictorial snapshot illustrating an EDX image of graphene oxide nanosheets in accordance with one or more embodiments of the present invention;
[0031] Fig. 2A is a graphical representation illustrating a full XPS spectra of K-doped GO in accordance with one or more embodiments of the present invention;
[0032] Fig. 2B is a graphical representation illustrating an XPS spectra showing the binding energy of potassium in accordance with one or more embodiments of the present invention;
[0033] Fig. 2C is a graphical representation illustrating fluorescence emission response of K-doped GO at different excitations in accordance with one or more embodiments of the present invention; [0034] Fig. 2D is a graphical representation illustrating an absorption spectra and emission spectra in accordance with one or more embodiments of the present invention;
[0035] Fig. 3 is a tabular representation illustrating different cases of pristine in accordance with one or more embodiments of the present invention;
[0036] Fig. 4 A is a pictorial snapshot illustrating microscopic images illustrating biocompatibility and bio-imaging of K-doped GO in non-tumorigenic ovarian epithelial IOSE in accordance with one or more embodiments of the present invention;
[0037] Fig. 4 B is a graphical snapshot illustrating cell viability MTT assay of K-doped GO in accordance with one or more embodiments of the present invention;
[0038] Fig. 4 C is a flow cytometry data snapshot illustrating the live and dead cell populations after staining in accordance with one or more embodiments of the present invention;
[0039] Fig. 4D is a pictorial snapshot illustrating confocal microscopic images of cells using K- doped GO as fluorescent probe in accordance with one or more embodiments of the present invention; [0040] Fig. 5 is a pictorial snapshot illustrating a K- doped GOs in a normal light and UV in light of 365 nm in accordance with one or more embodiments of the present invention;
[0041] Fig. 6 is agraphical snapshot illustrating XRD of K-doped graphene oxide in accordance with one or more embodiments of the present invention;
[0042] Fog.7 is a graphical snapshot illustrating TGA of K-doped graphene oxide in accordance with one or more embodiments of the present invention;
[0043] Fig. 8 A is a graphical snapshot illustrating XPS Cls spectra of K-doped graphene in accordance with one or more embodiments of the present invention; [0044] Fig. 8B is a graphical snapshot illustrating Ols spectra of K-doped graphene in accordance with one or more embodiments of the present invention;
[0045] Fig.9 is a flow chart illustrating a hydro-solvo-thermal graphene oxide synthesis method to obtain potassium-doped graphene oxide in in accordance with one or more embodiments of the present invention;
[0046] Fig. 10 is pictorial snapshot illustrating the hydro-solvo-thermal graphene oxide synthesis method to obtain potassium-doped graphene oxide in in accordance with one or more embodiments of the present invention.
DETAILED DESCRIPTION
[0047] Various embodiments of the present invention relate to hydro-solvo-thermal graphene oxide synthesis method to obtain potassium-doped graphene oxide. Moreover, the principles of the present invention and their advantages are best understood by referring to FIG. 1 to FIG. 10.
[0048] Although the foregoing description of the present invention has been shown and described with reference to particular embodiments and applications thereof, it has been presented for purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the particular embodiments and applications disclosed. It will be apparent to those having ordinary skill in the art that a number of changes, modifications, variations, or alterations to the invention as described herein may be made, none of which depart from the spirit or scope of the present invention. All such changes, modifications, variations, and alterations should therefore be seen as being within the scope of the present invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.
[0049] The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present disclosure is defined by the appended claims and equivalents thereof.
[0050] References within the specification to “one embodiment,” “an embodiment,” “embodiments,” or “one or more embodiments” are intended to indicate that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. The appearance of such phrases in various places within the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Further, various features are described which may be exhibited by some embodiments and not by others. Similarly, various requirements are described which may be requirements for some embodiments but no other embodiments.
[0051] Fig. 1A is a graphical representation illustrating a Raman spectra of graphene oxide nanosheets in accordance with one or more embodiments of the present invention. In particular, the Raman spectrum of K-doped GOs illustrates two signature peaks for carbon at 1312cm-1 and 1531cm-1 corresponds to D and G bands, respectively. The D and G bands correspond to the disordered structure in crystalline of sp2 cluster and the in-plane stretching vibration mode E2g of single-crystal graphite.
[0052] In accordance with one or more embodiments of the present invention, the synthesis of the K- doped graphene oxide is done by solvothermal process. During the process, the growth of the sp2 hybridized carbon atoms from sp3 hybridized carbon atoms of the white part of the oak fruit (majorly contains cellulosic sp3 carbon atoms) is initiated within the system as the temperature reaches the maximum of boiling temperature of the solvent systems taken for the process. The solvothermal route leads the carbonization of the cellulosic carbon atoms by developing sp2 bonded carbon atoms as the intermediate, which in turns of stabilizing concerns, converted into sheet like structure of graphitic form of carbon. The Raman spectroscopy performed confirms the synthesis of graphene and assess the quality.
[0053] Fig. IB is a graphical representation illustrating a Fourier transform infrared spectra of potassium doped graphene oxide in accordance with one or more embodiments of the present invention. In particular, the Fourier transform infrared spectra is performed to identify the presence of different functional groups on the surface of graphene oxide nanosheets. Moreover, the characteristic peaks at 3410cm-1 (nstr of O-H), 1709cm-1 (nstr of C=0), 1618cm-l (nstr of C-C), 1204cm-1 (epoxy symmetrical ring deformation vibration) and 1042cm-1 (nstr of C-O) confirms the presence of carbonyl, hydroxyl and epoxy groups on graphenenanosheets.
[0054] Fig. 1C is a pictorial snapshot illustrating a TEM image of graphene oxide nanosheets in accordance with one or more embodiments of the present invention. In particular, the TEM image of K-doped GOs shows uniform size of synthesized graphenenanosheets.
[0055] Fig. ID is a pictorial snapshot illustrating an EDX image of graphene oxide nanosheets in accordance with one or more embodiments of the present invention. In particular, to confirm the presence of potassium STEM-EDXS spectrum is analyzed. Moreover, the results indicate highly uniform dispersion of potassium (6.8wt %) on graphenenanosheets. Furthermore, X-ray photoelectron spectroscopy (XPS) is carried out for surface characterization of K-doped GOs. Furthermore, the excellent natural doping of potassium into oak fruit based GO is confirmed by the most accurate and advance elemental detection technique EDX for the confirmation of doping. The doping percentage is found to be 6.8% for potassium and the corresponding results.
[0056] Fig. 2A is a graphical representation illustrating a full XPS spectra of K-doped GO in accordance with one or more embodiments of the present invention. In particular, the full XPS spectra of K-doped GOs has three peaks at 284.4, 291.8 and 532eV attributed to Cls, K2P and Ols respectively.
[0057] Fig. 2B is a graphical representation illustrating an XPS spectra showing the binding energy of potassium in accordance with one or more embodiments of the present invention; [0058] Fig. 2C is a graphical representation illustrating fluorescence emission response of K-doped GO at different excitations in accordance with one or more embodiments of the present invention; In particular, the concentration is 0.02 mg/mL in Double distilled water inset shows normalized fluorescence spectra. Moreover, the excitation dependent property of synthesized K-doped GO, scans ranging from 330 to 5 lOnm (20nm l excinterval) are collected with its emission response. Further, the results plotted in Fig. 2C indicate that the emission of K-doped GOs is excitation dependent. The normalized fluorescence spectra plotted in the inset shows clear red shift of fluorescence intensity with the excitation wavelength of K-doped GOs.
[0059] Fig. 2D is a graphical representation illustrating an absorption spectra and emission spectra in accordance with one or more embodiments of the present invention. In particular, the absorption spectra and emission spectra has an excitation at 370 nm of K-doped GO. Moreover, blue fluorescence is observed when exposed to UV light of 365 nm.
[0060] The two different peak satellites corresponding to K2P3/2 at 292.3 and K2P1/2 at 294.8eV [34] are obtained. The XPS data validates the presence of functional groups (carbonyl, hydroxyl and epoxy groups) on graphenenanosheets. The spectroscopic properties of synthesized K-doped GO dispersed in double distilled water. The K-doped GO solution shows strong absorption in the wavelength range 240-380 nm with maximum at 270nm due to p-p* transition with a black dark line. The wide absorption range is a result of diverse size of K-doped GOs dispersed in water and K-doped GO shows emission maxima at 461nm on excitation at 370 nm.
[0061] Fig. 3 is a tabular representation illustrating binding energy (EB) for each of the adsorption cases of pristine in accordance with one or more embodiments of the present invention. The binding energy for each adsorption case is denoted in the respective images. Furthermore, the balls indicate carbon and potassium atoms.
[0062] In particular case to identity the favorable adsorption sites of Potassium (K) on GO surface, Density Functional Theory (DFT) is performed calculations of potassium adsorption on various possible sites of pristine, defected and bilayer graphene, as shown in Fig. 3. Though the experiments are performed with GO, the computations utilized graphene to avoid unnecessary computational cost. The computations have been performed using Quantum ATK, a DFT based Ab-initio code. The Perdew-Burke-Emzerhof (PBE) functional within Generalized Gradient Approximation (GGA) has been utilized to describe the exchange-correlation interaction energy of electrons. The semi-empirical Grimme DFT-D2 correction has been used to define the Vander Waals interaction between potassium and graphene sheet. The valence electrons are described by localized pseudo atomic orbitals with double zeta polarized basis set, and a large density mesh cut off of 130 Hartree considered for accuracy of calculations. The geometry relaxations of 4*4 hexagonal super cells have been performed using 12*12*1 Monkhorst-Pack grid of k-points. [0063] The cases 1-3 of the table illustrates a top view and a side view of pristine, case-4 illustrates defected pristine, case-5 illustrates bilayer graphene on adsorption of Potassium (K).
[0064] In particular, the binding energy of potassium adsorption on the carbon atom site (case-1), bridge site (case-2) and hollow site (case-3) of pristine graphene are 1.30eV, 1.3 leV and 1.37eV, respectively, inferring the relatively strong chemisorption of potassium towards the hollow site of pristine graphene in comparison to carbon and bride sites. Moreover, the binding energy of potassium adsorption at the vacancy site of defected graphene (case-4) is the highest (2.4 leV) among all the five adsorption cases studied. Where, the trigonal pyramidal shape of potassium at the vacancy defect site indicates possible sp3 hybridization undergone by the potassium atom. Since, the synthesized GO contains multi-layered structure; we have also studied the intercalation of potassium into bilayer graphene (case-5). The binding energy of potassium intercalation into bilayer graphene is the least (0.44eV) of all the five cases. Moreover, the intercalation has resulted in increased inter-layer distance of bilayer graphene from 3.32Ά to 4.90A. The obtained results show that the potassium atoms are most likely chemisorbed on the vacancy defect sites and hollow sites (hexagonal rings) of the synthesized GO, owing to their high binding energies. The probability of potassium intercalation into the GO layers is very low as evidenced from the very low binding energy and the intercalation induced structural distortion. After a well-defined characterization of K-doped GO with desired optical and chemical properties, we were interested to check whether our synthesized K-doped GO could be utilized for bio-imaging applications.
[0065] Fig. 4 A is a pictorial snapshot illustrating microscopic images illustrating biocompatibility and bio-imaging of K-doped GO in non-tumorigenic ovarian epithelial IOSE-364 cells in accordance with one or more embodiments of the present invention. Typically, the biological endpoints used in cell viability testing include morphological assessment using phase contrast microscopic images and cell viability and proliferation assays such as MTT (dimethylthiazol-diphenyltetrazolium bromide), sulforhodamine B (SRB) and others. Overall, recent studies reported that SRB assay provided a better linearity with cell number and higher sensitivity, and its staining was not cell line dependent.
[0066] In particular, the cells are stained with Sulphorhodamine B after treatment with different concentrations of K-doped GO for 24 h. Therefore, at first to determine the cytotoxic effect of those compounds, we performed Sulphorhodamine B colorimetric assay using IOSE-364 cells are evaluated by measuring the half maximal inhibitory concentration (IC50) in comparison with the untreated control as described previously. The cytotoxic effect was also assessed by flow cytometry with staining of Propidium iodide.
[0067] The biocompatibility study of the synthesized K-doped GO compounds is performed using non tumorigenic ovarian epithelial IOSE-364 cells. In brief, 5000 cells are seeded into each well of 96 well microtiter plates and exposed to various indicated concentrations of K-doped GO for 24 hours. Then cells are fixed in situ by the gentle addition of 50pL of cold 30% (w/v) TCA (final concentration, 10% TCA) and incubated for 30 minutes at 4°C, followed by stained with sulforhodamine B (SRB) solution at 0.4% (w/v) in 1% acetic acid, after which the excess dye is removed by washing with 1% acetic acid. The protein bound dye is subsequently solubilized in 10 mMTris base for OD determination at 565nm using Spectrophotometer.
[0068] Fig. 4 B is a graphical snapshot illustrating cell viability MTT assay of K-doped GO in accordance with one or more embodiments of the present invention. In particular the cell viability MTT assay is performed at different indicated concentrations using IOSE-364 cells for 24 hours and 48 hours. Moreover, the results reveal that the cell viability is>90% at a concentration of 30pg/mL and IC value of >50pg/mL.
[0069] The cells at a concentration of 5000 cells/well are seeded in 96 well micro titer plates and exposed to various concentrations (0, 10, 20, 30, 40 and 50pg/mL) of K-doped GO. Moreover, a relative cell survival percentage is determined using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide) assay after treatment for 24 hours and 48hours. The MTT (5mg/mL) is added into each well and incubated for 4 hours at 37°C. The formazan crystals formed are dissolved in DMSO. The intensity of colored formazan formed is determined by measuring the absorbance at 570nm using ELIS Areader.
[0070] In particular, 80% cell viability after treatment with K-doped GO for 48h at highest concentration of 50pg/mL, suggesting that the compound is non-toxic to the ovarian epithelial cells. [0071] Fig. 4 C is a flow cytometry data snapshot illustrating the live and dead cell populations after staining in accordance with one or more embodiments of the present invention;
[0072] Fig. 4D is a pictorial snapshot illustrating confocal microscopic images of cells using K- doped GO as fluorescent probe in accordance with one or more embodiments of the present invention. Particularly, the stable blue fluorescence properties for the water-soluble potassium-doped Graphene Oxides, when the non-tumorigenic ovarian epithelial IOSE-364 cells are incubated with K-doped GOs for 4 hours. Moreover, the epithelial IOSE-364 cells are washed, and images are taken using fluorescence microscope. Thus, showing a good biocompatibility, intracellular localization, and strong PL properties of the synthesized K-doped GOs demonstrated to be an excellent bio-imaging agent holding great promise in analytical and biological fields.
[0073] Fig. 5 is a pictorial snapshot illustrating a K- doped GOs in a normal light and UV in light of 365 nm in accordance with one or more embodiments of the present invention. In particular the UV- visible electronic absorption spectra measurements are carried out in Agilent Cary 100-UV-visible Spectrophotometer. The fluorescence emission spectra are measured using Varian Cary Eclipse spectrofluorometer. A strong blue fluorescence is observed at UV light of 365nm.
[0074] In accordance to one or more embodiments of present invention, the maximum assay of potassium in the graphene oxide sheets, plays significant role for the human beings, as demonstrated by the one of the applications of the K-GO in bio imaging of the cancerous cells. Further, other studies showed that the presence of potassium in graphene oxide showed the high superconductivity behavior which could reveal another important part of the synthesized material in near future.
[0075] In particular, the Raman (Research India, RIRM-LP1519; with 532nm excitation), FT-IR (Perkin Elmer), X-ray photoelectron spectroscopy (XPS) (Physical Electronics make PHI 5000 Versa Probe III spectrometer using A1 Ka radiation (1486.6eV)), TEM (JEOL, JEM 2100 microscope), and TGA (PerkinElmer, TGA 4000 thermal analyzer) are performed to investigate the chemical composition, and morphology of the prepared nano conjugates. Moreover, an X-ray diffraction (XRD) is performed using a Cu-Ka radiation of wavelength l= 1.5418 A.
[0076] Fig. 6 is agraphical snapshot illustrating XRD of K-doped graphene oxide in accordance with one or more embodiments of the present invention. In particular, the XRD technique is also employed for the prepared nanosheets having diffraction peaks at 20=13.6, 20=27.1 and 20=39.0 to confirm the purity of the synthesized graphene oxide. Moreover, the thickness and number of graphene layers are calculated by XRD wherein the number of layers of K-doped GO sheets obtained from dividing the crystal size (C) by the interlayer distance (d) added to the thickness of one graphene sheet (0.1nm).The crystal size (C) was calculated with the help of Scherrer equation. The interlayer distances (d) in the graphene were estimated using Bragg's Law. The crystal size of K-doped GO against the diffraction peak at 20=13.6 is 2.4nm. The inter planar distance is 0.65 nm. According to the XRD data, there are about four graphene layers in the K-doped GO.
[0077] Fog.7 is a graphical snapshot illustrating TGA of K-doped graphene oxide in accordance with one or more embodiments of the present invention. To further evaluate the graphitic nature of synthesized graphene oxide sheets, thermo-gravimetric analysis (TGA) has been performed, where weight loss of graphenenanosheets took place in two stages i.e. at 180°C to 325°C and 400°C to 685°C. The first stage weight loss from 180°C to 325°C shows the removal of chemisorbed water molecules and oxygen associated functional groups in the graphenenanosheets. The second stage weight loss (400°C to 685°C) demonstrates notable evidence about the oxidation of carbon skeleton of graphenenanosheets. A 2.10% residual weight at 675°C indicated the presence of higher number of functional groups at graphenenanosheets.
[0078] Fig. 8 A is a graphical snapshot illustrating XPS Cls spectra of K-doped graphene in accordance with one or more embodiments of the present inventiomParticularly, the binding energy values of K-doped GOs obtained from high resolution spectrum for Cls, Ols and K2p confirms that carbon has three different chemical environments for K-doped GOs at 284.5eV, 285.8eV, and 288.6eV for C=C, C-C/C-H and C=0, respectively.
[0079] Fig. 8B is a graphical snapshot illustrating Ols spectra of K-doped graphene in accordance with one or more embodiments of the present invention. In particular, the binding energy values for Ols shows oxygen has two different chemical environments for K-doped GOs corresponding to CO at 529.9eV and C=0 at 530.8eV. [0080] Fig.9 is a flow chart illustrating a hydro-solvo-thermal graphene oxide synthesis method to obtain potassium-doped graphene oxide in in accordance with one or more embodiments of the present invention. In particular the one step hydro-solvo-thermal graphene oxide synthesis method 900 to obtain potassium-doped graphene oxide for bio-sensing and bio-imaging of one or more natural occurring source starts at step 905.
[0081] At step 905 Quercus ilex fruit is collected and prepared for the hydro-solvo-thermal graphene oxide synthesis.
[0082] In particular, the Quercus ilex fruit is collected and prepared by mechanically separating outer shell and inner white part of the plurality of Quercus ilex fruit, cleaning the inner white part with double distilled water, removing outer layers to remove a plurality of solid impurities from the plurality of Quercus ilex fruit. Moreover, protecting the outer layers of Quercus ilex fruit in a protected medium to maintain the purity of the outer layers.
[0083] The step 905 proceeds to step 910. AT step 910, the prepared Quercus ilex fruit is subjected to solvothermal grinding using a solvent mixture to obtain a crushed extract paste. Particularly, the solvent mixture further comprises ethanol and double distilled water.
[0084] Moreover, the solvothermal grinding further includes crushing a predefined quantity the protected outer layers of the plurality of Quercus ilex fruit using mortar to form a crushed extract, grinding the white part of Quercus ilex fruit by a nano ball-mill machine. Furthermore, mixing a predefined quantity (4grams) of the white part mixed with a predefined volume (20mL) of the each solvent in a molar ratio of 1 : 1 to obtain a mixture and heating the mixture in an oven at a temperature of 120 °C for 4 hours to obtain a brown coloured solid residue. The crushed extract paste is heated at a temperature of 120°C for 4 hours in an oven. Subsequently, heating initiates growth of multiple graphitic sheets.
[0085] The step 910 proceeds to step 920. At step 915, the brown residue is subjected to coefficient separating. Particularly, the coefficient separating includes crushing the brown residue in the mortar to form a crushed brown solid residue, dispensing the crushed brown solid residue in a predefined volume of double distilled water using magnetic stirrer for 30 minutes. Moreover, centrifuging the dispensed crushed brown solid residue in a centrifuge having 7000 rotations per minute (rpm) for 15 minutes at room temperature to obtain said uniform brownish solution.
[0086] The step 915 proceeds to step 920. At step 920, the uniform brownish solution undergoes nanofiltration to obtain a clear brownish solution. Particularly, the nanofiltration is a particle filtering method. Moreover, nanofiltration uses a 0.2 um nylon filter paper to obtain the clear brownish solution. Furthermore, the brownish solution is subjected to successive filtration to obtain a clear brownish solution.
[0087] The step 920 proceeds to step 925. At step 925, the clear brownish solution is dried in an oven to evaporate solvent mixture to obtain a dried brown solid. In particular, the dried brown solid is potassium-doped graphene oxide. In particular, the drying temperature is chosen as 100 °C, to allow the different solvents to evaporate and to stabilize the resultant products without finding its non- reduced form.
[0088] The step 925 proceeds to step 930. At step 930, the potassium-doped graphene oxide obtained is characterized for bio-sensing and bio-imaging of at least one naturally occurring source. Particularly, the characterization confirms that the dried brown solid material is as K-doped GO by various characterization techniques including RAMAN, FT-IR, TEM and alike techniques.
[0089] In accordance with one or more embodiments of the present invention, the weight of the potassium-doped graphene oxide is 4 mg. [0090] In accordance with one or more embodiments of the present invention, the concentration of potassium-doped graphene oxide in a solution is 4 mg/mL.
[0091] In accordance with one or more embodiments of the present invention, the natural occurring source is a natural occurring source metal.
[0092] Fig. 10 is pictorial snapshot illustrating the hydro-solvo-thermal graphene oxide synthesis method to obtain potassium-doped graphene oxide in in accordance with one or more embodiments of the present invention.
[0093] Table 1 given below illustrates the effect of temperature on synthesis of potassium-doped graphene oxide compounds. In particular the table 1 shows an analysis at various low to high temperature ranges:
Figure imgf000015_0001
Figure imgf000016_0001
[0094] Fig. 11 is a pictorial snapshot illustrating use of the graphene oxide as a sensor for detection of iron in water, in accordance with yet another embodiment of present invention. In particular Fig. 11 illustrates triple distilled water with 10].il K-doped graphene oxide (left) and lmM Fe3+ in triple distilled water with 10m1 K-doped graphene oxide.
[0095] The presence of iron above the permissible range (3mg/L) in drinking water have negative effects leading to hemochromatosis which can cause damage to the liver, heart. The water of north India region basically contains high concentration of iron. According to bureau of Indian standard the permissible range of iron for drinking water is 300ppb. The synthesized graphene oxide plays a great role in field of iron detection as it change the transparent colour of iron containing water into black colour . Moreover, the graphene oxide is naturally doped with potassium and plays a critical role in adjusting the electronic properties of the carbon materials. Doped carbon nanomaterials is used for the detection of pollutants present in polluted water. The potassium doped graphene oxide detects the presence of iron selectively in water samples and plays a great role in field of sensor to detect heavy metal i.e. ion present in water samples.The brownish solution of synthesized K-doped GO shows bright blue fluorescence under UV light and exhibits the selective quenching of fluorescence in presence of iron. Thus, making potassium doped graphene oxide an excellent probe for visual detection of iron.
[0096] Fig. 12 is a graphical snapshot illustrating PL emission spectra of K-doped GO under different excitation wavelength from 330 to 490 nm in accordance with yet another embodiment of present invention. Particularly, the synthesized K-doped GO represent the excitation dependent emission behavior and shows emission maxima at 430nm when excited at 330nm The significant quenching of fluorescence intensity in case of iron indicates its selectivity towards the detection of iron in presence of other metals which are Li+, Na+, Mg2+, Al3+, K+, Ca2+, Mn2+, Fe3+, Co2+, Ni2+, Zn2+, Ag+, Cd2+, Cs+ and Ba2+.
[0097] Fig. 13 is a graphical snapshot illustrating metal stability of K-doped GO in the presence of different metal ions in accordance with yet another embodiment of present invention. In particular, the selectivity studies are carried out using fluorescence spectrophotometer which reveals that our material i.e. K-doped GO can selectively detect Fe (III) ions. Moreover, the fluorescence properties of K-doped GO was quenched in presence of Fe3+ ion while with the other metal ions quenching is almost negligible or there is no quenching due to the exceptional coordination between Fe3+ ion and hydroxyl group of K-doped GO.
[0098] Fig. 14 is a graphical snapshot illustrating interference study of K-doped GO in the presence of different metal ions in accordance with yet another embodiment of present invention. In particular, plot between 1-F/F0 v/s metals at 450nm emission maxima, where F is emission intensity of the metal ions at emission maxima and F0 is emission intensity without metal at emission maxima. For K-doped GO the value of 1-F/F0 is zero and for Li+, Na+, Mg2+, Al3+, K+, Ca2+, Mn2+, Fe3+, Co2+, Ni2+, Zn2+, Ag+, Cd2+, Cs+ , Ba2+ the values of 1-F/F0 are 0.07,0.07, 0.1, 0.1, 0.06, 0.07, 0.18, 0.88, 0.14, 0.28, 0.1,0.1, 0.1, 0.14, 0.07 respectively. Moreover, the influence of other metals which are present in water samples while the detection of iron is inferred via interference study and this study shows that the influence of other metal ions is almost negligible.The high contain of potassium in the precursor and the functionalization with oxygen containing functional groups leads the selective interaction with iron present in water and result the quenching of fluorescence intensity. Although the quick response of this sparking material towards the detection of iron makes this an excellent probe for iron sensing. Fluorescence quenching effect of the K-doped GO in the presence of Fe3+ ion provided a platform for detecting Fe3+ ion from aqueous solution with detection limit 0.345X 107 M.
[0099] Fig. 15 is a graphical snapshot illustrating Plot for limit of detection in accordance with yet another embodiment of present invention. In particular, the fluorescence quenching effect of Fe3+ is performed to explore the sensitivity of K-doped GO toward Fe3+ ion concentration. As shown in Fig. 15, the fluorescence intensity decreased with increasing Fe3+ concentration. A relation of the relative intensity F0/F with different Fe3+ concentrations. The fluorescence quenching efficiency is described by the Stem-Volmer plot with a perfect linear behavior (the linear correlation coefficient was (0.987) in the range of Fe3+ concentrations from 1X10-7 M to 10X10-7 M. The detection limit is as low as 0.345X10-7M (34.5 nM) using the formula 3o/m, where s was the standard deviation of blank sample signal and m was the slope of the linear fit.
[00100] Therefore, as may be seen, various embodiments of the present invention, as herein described above illustrate a method for the synthesis of a potassium-doped graphene oxide from a Quercus ilex fruit for bio-sensing and bio-imaging. The advantage of the present invention is that the present method a facile, eco-friendly and cost effective hydrothermal route for the synthesis of potassium doped graphene oxide (K-doped GO) from agricultural waste i.e. Quercus ilex Fruit by naturally preparing potassium doped blue graphene oxide sheets (PDGOs) by thermal treatment of the waste part of Quercus ilex (oak) fruit. The prepared K-doped GO sheets are highly water-soluble and emitted excellent bright blue fluorescence under UV-light. Moreover, the GO obtained has excellent bio-imaging with excellent natural doping of potassium.
[00101] The most valuable advantage is use of ecologically harmless (non -polluting) and purely organic solvents which are harmless to human health with leaving no side effects at all. replacing the toxic chemicals.
[00102] This invention is a new insight for the various bio imaging and bio-sensing industries not only due to its ecofriendly approach but also due to the fine qualitative productions of naturally potassium doped graphene. Along with this the ecofriendly K- doped graphene can act as the valuable agent for the treatment of various vital disease such as cancer. The results are in support of cancerous cell detection to cancerous cell destruction which is a spanking tool for the development of new drugs of cancer like vital disease in various bio-medical industries.

Claims

We Claim,
1. A hydro-solvo-thermal graphene oxide synthesis method to obtain potassium-doped graphene oxide for bio-sensing and bio-imaging, wherein said method comprising: collecting and preparing a plurality of Quercus ilex fruit for said hydro-solvo-thermal graphene oxide synthesis; solvothermal grinding of said plurality of Quercus ilex fruit in a solvent mixture to obtain a crushed extract paste of a brown solid residue; coefficient separating by centrifuging said brown residue to obtain said uniform brownish solution; nano filtering said uniform brownish solution using a nylon filter paper to obtain a clear brownish solution; drying said clear brownish solution in an oven to evaporate said solvent mixture to obtain a dried brown potassium-doped graphene oxide solid; performingbio-sensing and bio-imaging of at least one natural occurring source based on said potassium-doped graphene oxide.
2. The hydro-solvo-thermal graphene oxide synthesis method as claimed in claim 1, wherein said solvents mixture further comprises ethanol and double distilled water.
3. The hydro-solvo-thermal graphene oxide synthesis method as claimed in claim 1, wherein said collecting and preparing further comprising: mechanically separating outer shell and inner white part of said plurality of Quercus ilex fruit; cleaning said inner white part with double distilled water; removing outer layers to remove a plurality of solid impurities from said plurality of Quercus ilex fruit; protecting said outer layers of said plurality of Quercus ilex fruit in a protected medium to maintain the purity of said outer layers.
4. The hydro-solvo-thermal graphene oxide synthesis method as claimed in claim 1, wherein said heating of said crushed extract paste is performed at a temperature 120°C for 4 hours in an oven and said heating initiates growth of a plurality of graphitic sheets.
5. Thehydro-solvo-thermal graphene oxide synthesis method as claimed in claim 1, wherein said solvothermal grinding further comprising: crushing a predefined quantity said protected outer layers of said plurality of Quercus ilex fruit using mortar to form a crushed extract; grinding said white part of said plurality of Quercus ilex fruit by a nano ball-mill machine; mixing a predefined quantity of said white part mixed with a predefined volume of said solvents in a molar ratio of 1: 1 to obtain a mixture; heating said mixture in an oven at a temperature of 120 °C for 4 hours to obtain a brown colored solid residue.
6. The hydro-solvo-thermal graphene oxide synthesis method as claimed in claim 1, wherein coefficient separating step further comprising: crushing said brown residue in the mortar to form a crushed brown solid residue; dispensing said crushed brown solid residue in a predefined volume of double distilled water using magnetic stirrer for 30 minutes; centrifuging said dispensed crushed brown solid residue in a centrifuge having 7000 rotations per minute (rpm) for 15 minutes at room temperature to obtain said uniform brownish solution.
7. The hydro-solvo-thermal graphene oxide synthesis method as claimed in claim 1, wherein said nano filtering is a particle filtering method using a 0.2 um nylon filter paper to obtain said clear brownish solution
8. The hydro-solvo-thermal graphene oxide synthesis method as claimed in claim 1, wherein said drying is carried out in an oven at a temperature of drying 100 °C.
9. The hydro-solvo-thermal graphene oxide synthesis method as claimed in claim 1, wherein weight of said potassium-doped graphene oxide is 4 mg and concentration of potassium- doped graphene oxide in a solution is 4 mg/mL.
10. The graphene oxide synthesis method as claimed in claim 1, wherein said natural occurring source is a natural occurring source metal.
PCT/IB2021/052158 2020-03-17 2021-03-16 Hydro-solvo-thermal graphene oxide synthesis method WO2021186334A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IN202011011434 2020-03-17
IN202011011434 2020-03-17

Publications (1)

Publication Number Publication Date
WO2021186334A1 true WO2021186334A1 (en) 2021-09-23

Family

ID=77770895

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/IB2021/052158 WO2021186334A1 (en) 2020-03-17 2021-03-16 Hydro-solvo-thermal graphene oxide synthesis method

Country Status (1)

Country Link
WO (1) WO2021186334A1 (en)

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102219211A (en) * 2011-04-16 2011-10-19 华南理工大学 Method for reducing and decorating graphene oxide by plant polyphenol and derivant thereof

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102219211A (en) * 2011-04-16 2011-10-19 华南理工大学 Method for reducing and decorating graphene oxide by plant polyphenol and derivant thereof

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
C. TEWARI ET AL.: "A simple, eco-friendly and green approach to synthesis of blue photoluminescent potassium-doped graphene oxide from agriculture waste for bio-imaging applications", MATER. SCI. ENG., vol. 104, 7 October 2019 (2019-10-07), pages 109970, XP085787257, DOI: 10.1016/j.msec.2019.109970 *

Similar Documents

Publication Publication Date Title
Wang et al. Biomass-derived nitrogen doped graphene quantum dots with color-tunable emission for sensing, fluorescence ink and multicolor cell imaging
Atchudan et al. Highly fluorescent nitrogen-doped carbon dots derived from Phyllanthus acidus utilized as a fluorescent probe for label-free selective detection of Fe3+ ions, live cell imaging and fluorescent ink
Jayaweera et al. Facile preparation of fluorescent carbon dots for label-free detection of Fe3+
Cao et al. A facile microwave-assisted fabrication of fluorescent carbon nitride quantum dots and their application in the detection of mercury ions
Cheng et al. Graphitic carbon nitride nanosheets: one-step, high-yield synthesis and application for Cu 2+ detection
Elango et al. Green synthesis, spectroscopic investigation and photocatalytic activity of lead nanoparticles
Kaur et al. Highly photoluminescent and pH sensitive nitrogen doped carbon dots (NCDs) as a fluorescent sensor for the efficient detection of Cr (VI) ions in aqueous media
Chakraborty et al. Sunlight mediated synthesis and antibacterial properties of monolayer protected silver clusters
Tewari et al. A simple, eco-friendly and green approach to synthesis of blue photoluminescent potassium-doped graphene oxide from agriculture waste for bio-imaging applications
Pramothkumar et al. A comparative analysis on the dye degradation efficiency of pure, Co, Ni and Mn-doped CuO nanoparticles
Saranya et al. Facile one pot microwave-assisted green synthesis of Fe2O3/Ag nanocomposites by phytoreduction: potential application as sunlight-driven photocatalyst, antibacterial and anticancer agent
Kathiravan Green synthesis of silver nanoparticles using different volumes of Trichodesma indicum leaf extract and their antibacterial and photocatalytic activities
Mohan et al. Dual probes of Ag/Pd bimetallic NPs facilely synthesized by green process using Catharanthus leaf extract on textile dye removal and free radical capability
Harikrishnan et al. 2D/2D heterojunction of graphitic carbon nitride and hexagonal boron nitride nanosheets mediated electrochemical detection of hazardous hydroquinone with high selectivity and sensitivity
Li et al. Mn, B, N co-doped graphene quantum dots for fluorescence sensing and biological imaging
Singh et al. Role of green chemistry in synthesis and modification of graphene oxide and its application: A review study
Tayade et al. Green reduction of graphene oxide and its applications in band gap calculation and antioxidant activity
Yang et al. Hydrothermal synthesis of N, P co-doped graphene quantum dots for high-performance Fe 3+ detection and bioimaging
Xu-Cheng et al. Facile synthesis of bagasse waste derived carbon dots for trace mercury detection
Alam et al. Deciphering interaction between chlorophyll functionalized carbon quantum dots with arsenic and mercury toxic metals in water as highly sensitive dual-probe sensor
Roy et al. Rapid detection of hazardous H 2 O 2 by biogenic copper nanoparticles synthesized using Eichhornia crassipes extract
Roy et al. MoS2 Nanosheets@ Metal organic framework nanocomposite for enhanced visible light degradation and reduction of hazardous organic contaminants
Goyat et al. Modified low-temperature synthesis of graphene oxide nanosheets: Enhanced adsorption, antibacterial and antioxidant properties
Aggarwal et al. Cellulose-Derived Carbon Dots for Inner Filter Effect-Based Selective Sensing of Ofloxacin Antibiotics
Vasudha et al. Synthesis of BMA NPs using aloe vera gel for their electrochemical, biological and photocatalytic studies

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 21771938

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 21771938

Country of ref document: EP

Kind code of ref document: A1