KR101607575B1 - Carbon dot derivative from sugar alcohols and biological label comprising same - Google Patents

Abstract

Carbon nano-dot derivatives containing carbon nano dots derived from sugar alcohols and amine compounds passivated on the surface thereof are excellent in photoluminescence and biocompatibility and can be synthesized from sugar alcohols by a simple method. Therefore, in the biomedical field, .

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carbon nano-dot derivative derived from sugar alcohols and a biological marker comprising the same. BACKGROUND ART < RTI ID = 0.0 >

TECHNICAL FIELD The present invention relates to a carbon nano-dot derivative derived from sugar alcohols, a process for producing the same, and a biological label comprising the same. In particular, the present invention relates to carbon nano dots made from xylitol, which is a sugar alcohol derived from biomass using simple microwave-assisted pyrolysis.

Semiconductor quantum dots (QDs) over the last two decades have received attention as applications for biological markers, electronic devices, sensors and the like due to their high photoluminescence intensity, good light stability and variable emission wavelengths (X. Michalet et al , Science 2005, 307 , 538). Despite these advantages, application to the biological field of quantum dots has been limited due to toxicity of the Qdots and environmental concerns due to heavy metals (cadmium, lead, etc.) contained in Qdots (R. Hardman, Environ. Health Perspect. 2006, 114 , 165).

Carbon nanoparticles, also called carbon nano-dots or carbon dots (CDs), have biocompatibility, low toxicity and high stability as well as optical characteristics comparable to those of quantum dots and have recently become a substitute for quantum dots [SJ Yu et al . , J. Am. Chem. Soc. 2005, 127 , 17604). In particular, because of its excellent photoluminescence properties, carbon nanotubes are being applied to various fields such as bio-imaging, biosensor, drug delivery, photocatalyst, and solar power generation (SJ Zhu et al , Chem. Commun. 2011, 47 , 6858). There have been many studies to fabricate carbon nanotubes having desired dimensions and surface characteristics. For example, there have been many researches on manufacturing carbon nanotubes having a desired dimension and surface characteristics, and examples thereof include combustion method, laser fusing method, microwave-pyrolysis method, electrochemical oxidation method, silica mold synthesis method, Carbohydrate dehydration, etc. (HP Liu et al , Angew. Chem. Int. Ed. 2007, 46 , 6473) Reference). However, despite the recent advances in the synthesis of carbon nanotubes, the development of simple yet low cost, environmentally friendly methods is still required.

The carbon nanotubes are generally spherical and have a diameter of less than 10 nm. In addition, the carbon nano-dots are mixed states of sp ² - and sp ³ - hybrid carbon nanostructures, and have a conjugated carbon cluster form and are functionalized with other surface functional groups. Photoluminescence at the carbon nano-point is a combination of quantum confinement effect and emissive surface traps (SN Baker et al , Angew. Chem. Int. Ed. 2010, 49 , 6726). Surface passivation functionalities are known to enhance the photoluminescence of carbon nanotubes by increasing the number of surface defective sites (YP Sun et al , J. Am. Chem. Soc. 2006 , 128 , 7756).

Many carbon precursors such as sugars (glucose, fructose, sucrose, etc.), citric acid, and ascorbic acid are used to chemically synthesize carbon nano dots. However, despite the similar chemical structure, most of the sugar alcohols do not synthesize luminescent carbon nano-dots. Therefore, systematic studies are needed to synthesize highly light-emitting carbon nano dots from sugar alcohols.

 X. Michalet et al, Science 2005, 307, 538.  R. Hardman, Environ. Health Perspect. 2006, 114, 165.  S. J. Yu et al, J. Am. Chem. Soc. 2005,127,17604.  S. N. Baker et al, Angew. Chem. Int. Ed. 2010, 49, 6726.  Y. P. Sun et al, J. Am. Chem. Soc. 2006, 128, 7756.  S. J. Zhu et al., Chem. Commun. 2011, 47, 6858.  H. P. Liu et al., Angew. Chem. Int. Ed. 2007, 46, 6473.

Therefore, the present invention aims to provide a carbon nano-dot derivative derived from sugar alcohols excellent in photoluminescence and biocompatibility, and its use for bio-imaging.

The present invention also provides a method for producing the carbon nano-dots from a sugar alcohol by a simple and efficient method.

According to the above object, the present invention provides a carbon nano-dot derivative comprising a carbon nanodot derived from sugar alcohol and an amine compound passivated on the surface of the carbon nano-dot.

Further, the present invention relates to a method for producing a sugar alcohol, comprising: (a) mixing a sugar alcohol with an acid compound containing a chlorine component; (b) adding and stirring an amine compound to the product of step (a); And (c) carbonizing the resultant product of step (b).

The present invention also provides a biological marker for bioimaging comprising the carbon nanoscale derivative.

The carbon nano-dot derivatives according to the present invention are excellent in photoluminescence and biocompatibility, and can be synthesized from sugar alcohols by a simple method, and thus are useful as biomedical applications in biomedical fields and the like.

Hereinafter, the present invention will be described in more detail with reference to the drawings. The meanings of the abbreviations used in the following are described in detail for the purpose of carrying out the invention.
Figure 1: (a) picture showing one example schematically a method of synthesizing carbon nano from xylitol, (b) xylitol, UV / Vis absorption spectrum of CD _xy (0) and CD _xy (1), the insertion image sunlight and CD _xy (0) solution under UV light (365nm) (left) and CD _xy (1) solution (R), and (c) under which conditions change the excitation wavelength by 10nm intervals in 320 ~ 410nm range CD _xy (1 Dimensional photoluminescence spectrum.
Figure 2: (a) a high resolution TEM image of the TEM image and size distribution histogram of the _{CD xy (1), (b} ) CD xy (1), and (c) AFM with images of observing the height of the surface of the CD _xy (1) And graphs of them.
Fig. 3 : (a) quantum yield and (b) zeta potential of CD _xy according to various amounts of HCl added, wherein the quantum yield is measured at an excitation wavelength of 360 nm using quinine sulfate as a reference material.
Figure 4: (a) for different concentrations of the CD _xy (1) analysis of cell viability based on the MTT- WI-38 and HeLa cells treated with, and _{(b) CD xy (1)} 24 hours 100㎍ / mL Bright-field and fluorescence images of treated HeLa cells.
5 : Time-resolved photoluminescence decay curves of CD _xy (0) and CD _xy (1).
Fig. 6 : An image obtained by observing the surface height of CD _xy (0) with an AFM and a graphical representation thereof.
Figure 7: (a) xylitol, CD _xy (0) and the XPS spectrum of a FT-IR spectrum of the _{CD xy (1), (b} ) CD xy (0) and _{CD xy (1) (survey scan} ), and (c ) CD _xy (0) and (d ) a deconvolved high resolution XPS C 1s spectrum of CD _xy (1).
Figure 8 : Deconvoluted high resolution XPS Cl2p spectrum of CD _xy (1).
9 : The quantitative yields of CD _xy (a) and zeta potential (b) (the amounts of xylitol and HCl were all fixed to 1.0 mmol and the quantum yield was determined by using quinine sulfate as a reference material at a 360 nm excitation wavelength Lt; / RTI >
10 : UV / Vis absorption spectra of sorbitol, CD _sor (0) and CD _sor (1), insert image shows CD _sor (0) solution (left) and CD _sor (1) under sunlight and UV light (365 nm) Solution (right). (Quantum yields of CD _sor (0) and CD _sor (1) are 2.3% and 5.3%, respectively).

In the present specification, the unit "element%" described for the content of a specific element in a carbon nano-dot derivative means the number of atoms of a specific element relative to the total number of atoms such as carbon, oxygen, and nitrogen contained in the carbon nano- In percentages. The "original consumption (B / A)" of the element B with respect to the element A means the ratio of the number of atoms of the element B to the number of atoms of the element A.

Composition and properties of carbon nano-point derivatives

The carbon nano-point derivatives of the present invention include carbon nano dots derived from sugar alcohols and amine compounds passivated on the surfaces of the carbon nano dots.

The carbon nano-dot derivative mainly contains a carbon (C) component, and may contain, for example, from 40 to 75% by atom, more specifically from 50 to 65% by atom.

In addition, the carbon nano-dot derivative contains oxygen (O) and nitrogen (N) components in addition to carbon. The carbon nano-dot derivative may contain, for example, an oxygen (O) component in an amount of 15 to 40 atomic%, more specifically 20 to 35 atomic%. The carbon nano-point derivative may contain, for example, 1 to 20 atom%, more specifically 1 to 15 atom% of nitrogen (N) component.

In addition, the element ratio (O / C) of the oxygen component to the carbon component contained in the carbon nano-dot derivative may be, for example, 0.4 to 0.6, more specifically 0.45 to 0.55. The atomic ratio (N / C) of the nitrogen component to the carbon component contained in the carbon nano-dot derivative may be, for example, from 0.01 to 0.5, more specifically from 0.02 to 0.3.

In particular, the carbon nano-point derivative may contain a chlorine (Cl) component. For example, the carbon nano-dot derivative may contain 5 to 15 atomic%, more specifically 7 to 12 atomic%, and even more specifically 8 to 10 atomic% of the halogen component, especially the chlorine component.

(C), oxygen (O), and nitrogen (N) are contained in an amount of 50 to 55%, 15 to 30%, and 30%, respectively, when the carbon nano-point derivative contains a chlorine (Cl) , And 5 to 15% by atom, and the original consumption (O / C) and the original consumption (N / C) may be 0.45 to 0.50 and 0.20 to 0.30, respectively.

The amine compound may be, for example, a C _2-10 alkylenediamine, more specifically, ethylene diamine.

The sugar alcohols may be sugar alcohols derived from biomass. More specifically, the sugar alcohols may include xylitol, sorbitol, glycerol, or a mixture thereof, preferably xylitol.

The carbon nanotubes may have an average particle size of 1 to 10 nm, more preferably 2 to 8 nm, and more preferably 3 to 6 nm.

The carbon nano-dot derivatives may emit various colors. For example, the carbon nano-dot derivatives may emit blue, green, and red fluorescence, and the excitation wavelengths of the fluorescent light may be 395 to 415 nm, 463 to 483 nm, and 549 to 569 nm, respectively.

In addition, the carbon nanotubes derivatives may have very low cytotoxicity. Specifically, the carbon nanotubes may have a concentration of not less than 0.1 mg / mL with a cell viability of 95% or more.

The carbon nanotubes derivatives are more suitable for biomedical fields because they are more biocompatible than conventional semiconductor quantum dots. Specifically, carbon nanotubes derivatives exhibit excellent luminescence, water stability, and low cytotoxicity, and thus have high potential for biomedical applications. In particular, the carbon nanotubes derivatives may be useful as biological labels in the field of bio-imaging.

Method for producing carbon nano-dot derivatives

The carbon nano-point derivative can be obtained by carbonizing the sugar alcohol together with an acid compound and an amine compound containing a chlorine component.

Specifically, the carbon nano-point derivative can be prepared by a method comprising the steps of:

(a) mixing a sugar alcohol with an acid compound containing a chlorine component;

(b) adding and stirring an amine compound to the product of step (a); And

(c) carbonising the result of step (b).

Hereinafter, each step will be described in detail.

(a) mixing a sugar alcohol with an acid compound

This step is a pretreatment step in which sugar alcohol is mixed with a chlorine-containing acid compound to prepare for future surface passivation and carbonization processes.

The chlorine-containing acid compounds added in this step play an important role in improving the photoluminescence properties of carbon nanoparticles. First, the H ⁺ ion generated by the acid compound promotes the carbonation of the carbohydrate. In addition, the H ⁺ ion activates passivation of the amine compound on the surface of the carbon nanotubes. In addition, the Cl ^- ions generated by the acid compound are doped on the carbon nanoparticles, increasing the number of defective emissive sites of the carbon nanoparticles. As a result, the carbon nano-points synthesized by adding such an acid compound can exhibit better luminescence and higher quantum yield.

The acid compound may be hydrochloric acid.

The acid compound may be mixed in an amount of 0.1 mole to 3.0 mole, more preferably 0.5 mole to 1.5 mole, per 1.0 mole of the sugar alcohol. When the amount of the acid compound added is within the range, the optical characteristics and the like of the finally prepared carbon nano-dot derivative may be more excellent.

The specific types of sugar alcohols, which are raw materials of this step, are as exemplified above.

(b) Addition of amine compound

This step is a step of preparing the surface passivation by adding an amine compound to the resultant product obtained in the step (a).

Specific examples of the amine compound are as described above.

The amine compound may be added in an amount of 0.1 mole to 3.0 mole, more preferably 0.5 mole to 1.5 mole, per 1.0 mole of the sugar alcohol. When the addition amount of the amine compound is within the range, the optical characteristics and the like of the finally prepared carbon nano-dot derivative may be more excellent.

After the addition of the amine compound, it is preferable to stir sufficiently.

(c) Carbonization process

This step is a step of carbonizing the resultant obtained in the above step (b) to obtain a carbon nano-point derivative.

The carbonization can be performed by a pyrolysis process.

As a preferred example, the carbonization may utilize microwave-assisted pyrolysis. The microwave is not limited to its frequency and power range, but may be in the range of 2 to 4 GHz in frequency and 600 to 800 W in power, for example. In addition, although the processing time of the microwave is not limited, it is preferable that the time for the solvent to be sufficiently evaporated, so that it is preferable to increase the microwave treatment time as the amount of the solvent increases. As a specific example, when the solvent is about 5 to 15 mL, it is preferable that the microwave treatment time is 2 minutes to 5 minutes. As a result, it is possible to prevent the reaction from being excessively performed, and the water- The characteristics can be further increased.

When the above carbonization process is completed, a carbon nano-point derivative whose surface is passivated with an amine compound can be synthesized.

FIG. 1 (a) is a graphical representation of a method for producing a carbon nano-dot derivative according to an embodiment of the present invention, wherein xylitol is mixed with an amine compound and an acid compound (HCl) It is produced through pyrolysis.

Thus, according to the present invention, it is possible to synthesize carbon nanotubes whose photoluminescence is controlled from sugar alcohols such as xylitol by a simple microwave-pyrolysis method. Further, according to the present invention, its surface passivation reaction can be improved by adding an acid compound in the course of synthesizing carbon nanotod derivatives.

Specific examples and test examples

Hereinafter, the present invention will be described in more detail by way of examples. The following examples are illustrative of the present invention, but the present invention is not limited to the following examples.

Hereinafter, the term "CD" means a carbon nanodot (carbon dot or C-dot).

The term CD _xy (n) is the carbon nano-point synthesized from xylitol, where n represents the amount (in mmol) of HCl added prior to the microwave-assisted pyrolysis process.

The term CD _sor (n) is a carbon nano-point synthesized from sorbitol, wherein n is as described above.

Materials and raw materials :

- Xylitol and 1,2-ethylenediamine (EDA) were purchased from Sigma Aldrich.

- Hydrochloric acid (HCl) was purchased from Daejung Chemical (Korea).

Example 1: Preparation of carbon nano-dots (CD) from sugar alcohols (change in HCl addition amount)

152.15 mg (1.0 mmol) of xylitol was diluted in 10 mL of distilled water, and 1.0 M HCl was mixed in an amount ranging from 0 to 3 mL (0 to 3 mmol). 68 쨉 l (1 mmol) of EDA was mixed with the obtained mixture and vigorously stirred for 2 minutes. The resulting clear solution was placed in a commercial microwave oven (700 W) and heated for 2 minutes. After cooling to room temperature, the tan solid was diluted with distilled water and the salt and unreacted residues were removed using a syringe filter (0.45 μm). Thereafter, the reaction solution was dialyzed against distilled water for one day through a dialysis membrane (MWCO: 500-1000).

Example 2: Preparation of carbon nano-dots (CD) from sugar alcohols (change in EDA addition amount)

CD was synthesized by the same procedure as in Example 1 except that 1 M HCl was used in an amount of 1 mL (1.0 mmol), and the EDA was changed to CD (0 to 3 mmol) _xy were synthesized.

Test Methods

(1) Characteristic evaluation

Concentration control and comparison were performed by measuring the absorbance using a UV / Vis spectrophotometer (UV-2550, Shimadzu). The absorbance curves were compared to find the similarity between the concentrations, and the samples were then adjusted for comparison. Fluorescence data were measured using a fluorometer (Agilent). The size and shape of the CD were observed using a transmission electron microscope (TEM, JEM-2100, JEOL) and atomic force microscope (AFM, Dimension 3100, Veeco). Passivated functional groups were identified using XPS (K-alpha, Thermo Fisher), FT-IR (Agilent) and zeta potential meters (Malvern).

(2) Photoluminescence lifetime measurement

The exciton lifetime was derived by the time - correlated single photon counting method (TCSPC). A computer controlled diode laser having a 375 nm wavelength, a 54 ps pulse width and a 40 MHz repetition rate was used as an excitation source. The photoluminescence emission was spectroscopically calculated using a condensing means and a PicoQuant. Speed detection by the TCSPC module (PicoHarp 300E, PicoQuant) equipped with MCP-PMT (R3809U-5X series, Hamamatsu). The total instrument response function (IRF) of the photoluminescent decay was less than 30 ps and the temporal time resolution was less than 10 ps. The deconvolution of actual fluorescence decay and total instrument response (IRF) was processed with software (FlouFit, PicoQuant) to calculate the time constant associated with each exponential decay.

(3) Cell culture

HeLa cell lines derived from human epithelial carcinoma cells were cultured in DMEM (Dulbecco's Modified Eagle's Medium, Life Technologies) supplemented with 10% fetal bovine serum (FPS) and 1% penicillin-streptomycin. WI-38 cells derived from human diploid cells were cultured in RPMI (Roswell Park Memorial Institute) 1640 culture medium (Life Technologies) containing 10% fetal bovine serum, 25 mM sodium bicarbonate and 1% penicillin-streptomycin Lt; / RTI >

(4) Cell imaging

Fluorescence images of the cells were obtained using confocal laser scanning fluorescence microscopy (LCSM, FV1000 SPD). HeLa cells were inoculated into 8-chambered coverglass at a concentration of 2 x 10 < 4 > cells / well and cultured in 5% CO _{2 at} 37 ° C for 24 hours. After removing the culture, each well was washed with PBS. Each well was then replaced with 180 [mu] l of fresh culture and 20 [mu] l of 10x CD solution. After further incubation for 24 hours, optical and fluorescence images were obtained using LCSM.

Test result

Xylitol, CD _xy (0) and UV / Vis of CD _x y (1) absorption spectra, Fig. 1 (b) As seen, CD _xy (0) and CD _xy (1) broad absorption appeared to 230nm vicinity in the spectrum in Peak, which is a typical aromatic absorption peak associated with the sp ² carbon network. In addition, the strong UV / Vis absorption peak at 286 nm in the CD _xy (1) spectrum can be similarly observed at other carbon nano-points and is due to the n-π ^* transition of the C = O bond. Liu et al , Adv. Mater . 2012, 24 , 2037). CD _xy (1) was excited at 360 nm to emit bright blue fluorescence with a maximum emission wavelength of 446 nm, whereas no noticeable photoluminescence was observed for CD _xy (0) ( Fig. 1 Reference). For reference, the quantum yield (QY) of CD _xy (0) using quinine sulfate was determined to be 0.38%. However, in the case of CD _xy (1), the quantum yield was remarkably increased to 7.0% as HCl was added. This result is a result of conforming to the exciton lifetime of the time-correlated single photon counting method (TCSPC) the CD _xy (0) and CD _xy (1) measured by an indicating each and 1.75ns 2.63ns (Figure 5 and Table 1 ). According to the published to about dependent emission (excitation-dependent emission) so far (reference [HP Liu et al, Angew Chem Int Ed 2007, 46, 6473....]), 1 (- carbon nano here c) , the maximum photoluminescence emission wavelength of CD _xy tends to depend on the excitation wavelength. The generation of photoluminescence in various colors is caused not only by the particle size distribution of CD _xy but also by the distribution of emissive trap sites. The exciton lifetimes of CD _xy (0) and CD _xy (1) are shown in Table 1 below.

CD _xy (0) CD _xy (1) t1 (ns) 10.36 (0.11) 11.93 (0.09) t2 (ns) 3.08 (0.18) 3.74 (0.31) t3 (ns) 0.14 (0.71) 0.67 (0.60) X ² 1.00 1.08 t _average (ns) 1.75 2.63

The size and shape of CD _xy were measured using a transmission electron microscope (TEM) and an atomic force microscope (AFM) (see FIGS . 2 and 6 ). TEM images show that the CD _xy (1) particles are spherical and have an average diameter of 4.65 ± 1.21 nm. A high-resolution TEM image of CD _xy (1) shows a crystal structure with an interlayer spacing of 0.21 nm, which corresponds to the (100) lattice spacing of the graphite. Also, the AFM images show that the shapes of CD _xy (0) and CD _xy (1) are spherical and their average heights are 2.53 ± 0.06 nm and 3.38 ± 0.40 nm, respectively.

Using FT-IR and high-resolution X-ray photoelectron spectra (XPS), the effect of EDA and HCl addition on CD _xy synthesis was investigated more concretely. FT-IR spectroscopy revealed changes in functional groups during the reaction (see Fig. 7 (a) ). Peak (OH bending) in all CD _xy of the FT-IR spectrum 2800 - characteristic peaks at 3000 cm ^-1 (CH stretching), broad peak (OH stretching) in the vicinity of 3300cm ^-1, and 1000 ~ 1200cm ^-1 , Which means that the hydroxyl group is abundant like the precursor xylitol. In addition, the spectrum of CD _xy (0) shows a new peak at 1573 cm ^-1 and 1417 cm ^-1 , which corresponds to the asymmetric and symmetrical stretching vibration of the carboxylate group. In the spectrum of CD _xy (1), new peaks were observed: 3154 cm ^-1 (NH stretching), 1598 cm ^-1 (NH plane motion), and 1527 cm ^-1 and 1464 cm ^-1 (NH asymmetry and symmetric vibration) These clearly show that CD _xy (1) has been surface passivated to EDA. In addition, the structure was analyzed by performing XPS separately from FT-IR (see Fig. 7 (b) ). In addition, CD _xy (0) mainly contains carbon, oxygen and a small amount of nitrogen. The XPS element composition analysis results of CD _xy are summarized in Table 2 below.

division Content of each element (element%) Circulation of consumption among components C O N Cl N / C O / C CD _xy (0) 64.60 33.59 1.81 - 0.028 0.52 CD _xy (1) 52.51 25.69 12.38 9.42 0.24 0.49

As shown in Table 2 , the nitrogen content of CD _xy (1) was about 12.4%, which is higher than other nitrogen-doped and surface passivated carbon nanodots and only 1.8% for CD _xy (0) (See WB Lu et al , Anal. Chem . 2012, 84 , 5351). Thus, this result shows that the surface passivation by EDA of CD _xy is significantly improved by the addition of HCl. Also, CD _xy (1) contained about 9.4% of chlorine, which means that Cl-doped CD _xy (1) was formed (see FIG. 8 and Table 3 ), and this Cl-doping is defective emissive sites, which plays an important role not only in photoluminescence improvement but also in surface passivation activity. The results of XPS Cl composition analysis of CD _xy (1) are summarized in Table 3 below.

CD _xy (1) Dislocation (eV) area(%) Cl 2p _1/2 199.4 34.43 Cl 2p _3/2 197.7 65.56

As shown in Table 3, it was confirmed that the characteristics of CD _xy were improved by addition of HCl. In addition, the quantum yield and zeta potential changes with the amount of HCl added during the synthesis of CD _xy (n) (e.g., n = 0 to 3) were observed. 3 (a) shows the quantum yield of CD _xy measured by varying the amount of HCl added while the amount of xylitol and EDA (1.0 mmol) was fixed. The quantum yield increased to 7.0% as the amount of HCl was increased from 0 to 1.0 mmol. However, when the amount of HCl was further increased to 1.0 ~ 3.0 mmol, the quantum yield was not improved any more, To activate the surface passivation of CD _xy . In Figure 3 (b), the zeta potential of the CD _xy, and gradually increases from -24.0 ± 0.55mV for the CD _xy (0) was reached 10.0 ± 1.23mV for the CD _xy (1), this The same surface change shows that the surface of CD _xy is passivated to an amine group derived from EDA. A similar phenomenon was observed in the control experiment (see FIG. 9 ). As the amount of EDA increased, the quantum yield of CD _xy increased to approximately 7%, and when the amount of EDA exceeded 1.0 mmol, it showed a stagnant phase. In addition, while increasing the amount of EDA from 0 to 0.1 mmol, the zeta potential of CD _xy increased from -7.10 ± 0.78 mV to 10.0 ± 1.23 mV.

These results indicate that the addition of HCl has several important roles in improving the photoluminescence properties of carbon nanotubes. First, as has already been shown, the H ⁺ ion promotes the carbonation of carbohydrates. The H ⁺ ions also activate the passivation of the EDA on the CD _xy surface. In addition, Cl ^- ions are doped on the carbon nanodots to increase the number of defective emissive sites of CD _xy . Further, in order to further examine the influence of the addition of HCl on the photoluminescence properties of the carbon nano dots derived from sugar alcohols, tests were conducted on other sugar alcohols such as sorbitol (hexabody alcohol). As a result, as expected, the carbon nano dots (CD _sor (1)) synthesized from sorbitol with the addition of HCl showed lighter blue luminescence compared to carbon nano dots (CD _sor (0) And a high quantum yield (5.3%) (see Fig. 10 ).

Considering the simple synthesis of CD _xy and its photoluminescence properties and biocompatibility, CD _xy is useful as a biological marker for imaging living cells. The cytotoxicity of CD _xy (1), was evaluated using a cell viability measurement method (MTT assay) relative to both types of cell lines, i.e., HeLa and WI-38 cells: Referring to FIG. 4 (a), 0.1mg / mL The cell viability of the two cell lines maintained the best cell survival rate of about 100% and the cell survival rate started to decrease slightly from 1.0 mg / mL concentration.

The acceptable concentration of such CD _xy (1) is much higher than the typical concentration required for bioimaging. As a result, CD _xy (1) was treated with HeLa cells at a concentration of 0.1 mg / mL, which maintained high biocompatibility, and cultured for 24 hours. As shown in FIG. 4 (b) , the intracellular uptake of CD _xy (1) was clearly observed, bright fluorescence was mainly expressed in the cytoplasm, and not in the nucleus nucleus. Thus, it can be seen that CD _xy (1) can easily penetrate into the cells by intracellular ingestion. In addition, when HeLa cells were cultured together with CD _xy (1), luminescence of various colors was observed, and blue, green and red excited respectively at 405 nm, 473 nm and 559 nm, for example, were observed. The characteristics of the carbon nanotubes of the present invention exhibit bio-imaging characteristics that can not be observed from conventional organic dyes or quantum dots. Also, since no photobleaching phenomenon was observed through confocal laser scanning fluorescence microscopy analysis, it can be seen that the photon emission of carbon nanotubes is excellent.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, It is to be understood that the invention may be practiced within the scope of the appended claims.

The present invention is useful in the field of carbon nanotube-based technology, which has been rapidly increasing in the fields of advanced biotechnology and biomedical science.

Claims (15)

Carbon nanodots derived from sugar alcohols and containing a chlorine (Cl) component, and
And an amine compound passivated on the surface of the carbon nano dots.
delete The method according to claim 1,
Wherein the carbon nanotubes contain 8 to 10% by atom of the chlorine component.
The method according to claim 1,
Wherein the carbon nano dots are obtained by carbonization of sugar alcohols together with an acid compound and an amine compound containing a chlorine component.
The method according to claim 1,
(N / C) of the nitrogen component with respect to the carbon component contained in the carbon nano-dot is 0.02 to 0.3.
The method according to claim 1,
Wherein the sugar alcohols are sugar alcohols derived from biomass.
The method according to claim 6,
Wherein the sugar alcohols include xylitol, sorbitol, glycerol, or a mixture thereof.
The method according to claim 1,
Wherein the amine compound is a C _2-10 alkylene diamine.
(a) mixing the sugar alcohol with hydrochloric acid (HCl);
(b) adding and stirring an amine compound to the product of step (a); And
(c) carbonising the product of step (b).
A method for producing a carbon nano-point derivative according to claim 1.
delete 10. The method of claim 9,
Wherein in step (a), the hydrochloric acid is mixed in an amount of 0.1 to 3.0 moles per 1.0 mole of the sugar alcohol.
10. The method of claim 9,
Wherein in step (b), the amine compound is added in an amount of 0.1 mole to 3.0 mole based on 1.0 mole of the sugar alcohol.
10. The method of claim 9,
Wherein in step (c), the carbonization is carried out by a pyrolysis process.
14. The method of claim 13,
Wherein the pyrolysis step is microwave-assisted pyrolysis.
9. A biological marker for bioimaging comprising the carbon nanotope derivative of any one of claims 1 to 8.

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