CN108660185A

CN108660185A - A kind of biosensor and preparation method based on golden selenium key

Info

Publication number: CN108660185A
Application number: CN201810196104.2A
Authority: CN
Inventors: 唐波; 徐克花; 胡博; 姜璐璐
Original assignee: Shandong Normal University
Current assignee: Shandong Normal University
Priority date: 2018-03-09
Filing date: 2018-03-09
Publication date: 2018-10-16

Abstract

The invention discloses a kind of biosensors and preparation method based on golden selenium key.The Au S keys that gold nano-material surface is substituted using Au Se keys, are reconstructed traditional Au S keys nano platform (Au S NPF).This novel Au Se keys nano platform (Au Se NPF) is considered to have better performance effectively to avoid the distortion of the caused detection signal of intracellular high concentration mercaptan, and realizes intracellular high-fidelity imaging.

Description

A kind of biosensor and preparation method based on golden selenium key

Technical field

The present invention relates to biosensor technique fields, and in particular to a kind of biosensor and preparation side based on golden selenium key Method.

Background technology

Gold nano-material not only has the original chemical property of metallic gold, but also shows unique physical property, for example, with greatly Small and the relevant photoelectric property of pattern, higher specific surface area, good biocompatibility and chemical stability etc..Therefore, And it is widely used in the fields such as sensing, medicament transport, bio-imaging and treatment.Au-S covalent bonds are biomolecule and gold nano The common method that particle combines, mercapto-functionalized gold nano-material are widely used in fluorescence, optoacoustic, Raman, electrochemistry Bio-sensing field.However, under physiological environment, the recognition group that gold nano-material surface is supported on by Au-S keys is easy quilt The biological thiol of intracellular high concentration replaces, and causes the false positive results of detection.Au-S keys how are fundamentally solved to exist Intracellular unstable problem, avoids the distortion of testing result caused by biological thiol, for the nanometer based on nanogold Material is of great significance in the application of biological field.

Invention content

In order to solve the deficiencies in the prior art, an object of the present invention is to provide a kind of golden selenium key in biosensor Application, effectively avoid the distortion of detection signal caused by intracellular high concentration mercaptan, and realize intracellular high-fidelity at Picture.

To achieve the goals above, the technical scheme is that：

A kind of application of the gold selenium key in biosensor, sulfydryl (- SH) is formed with gold nano grain in biosensor Golden sulfide linkage replace with the golden selenium key that selenol group (- SeH) and gold nano grain are formed.

In traditional technology generally use Au-S covalent bonds (golden sulfide linkage or Au-S keys) by biomolecule and gold nano grain into Row combines and prepares biosensor, is found in the research process of the present inventor, the biology obtained in this way Sensor can lead to the distortion of testing result during detection.It is sent out after the reason of further research testing result is distorted Existing, the concentration in biological cell there are biological thiol is higher, and the essence of Au-S keys is a kind of covalent bond, and stability is poor, makes It obtains biomolecule to be easy to be replaced by intracellular biological thiol, so as to cause the distortion of testing result.So the hair of the present invention A person of good sense replaces Au-S keys with the higher gold selenium key (Au-Se keys) of stability, finds to divide gold nano grain and biology with Au-Se keys Son combines the biosensor formed to have better sensing capabilities, and caused by capable of effectively avoiding intracellular high concentration mercaptan The distortion of signal is detected, and realizes intracellular high-fidelity imaging.

Include the biomolecule with recognition group and Jenner the second object of the present invention is to provide a kind of biosensor Rice grain, the biomolecule with recognition group contain selenol group, and the selenol group forms gold with gold nano grain Selenium key makes biomolecule and gold nano grain with recognition group combine, and each gold nano grain and at least one band are insighted The biomolecule of other group combines.

The third object of the present invention is to provide a kind of above-mentioned biosensor in fluorescence sense, Raman sensing, light sound sensor And the application in electrochemical sensing field.

The fourth object of the present invention is to provide a kind of biosensor based on golden selenium key, including fluorescein, peptide chain and gold Nano particle, in the N-terminal of peptide chain, the C-terminal amino acid of the peptide chain contains exposed selenol group, described for the fluorescein modification Gold nano grain forms golden selenium key and peptide chain combination, each gold nano grain and at least one peptide chain combination by selenol group.

The fifth object of the present invention is to provide a kind of preparation method of the above-mentioned biosensor based on golden selenium key, by N-terminal The peptide chain for being modified with fluorescein is added into the dispersion liquid of gold nano grain, can be obtained after being protected from light stirring reaction in 36~72 hours Biosensor based on golden selenium key；Wherein, peptide chain C-terminal amino acid contains exposed selenol group.

The sixth object of the present invention is to provide a kind of above-mentioned biosensor based on golden selenium key in detection matrix metal egg White enzyme

(MMP) application in.

Detection matrix metalloproteinase application be non-disease Clinics and Practices for the purpose of.

Beneficial effects of the present invention are：

1. the present invention utilizes the traditional Au-S NPF of Au-Se bond reconstructions, it is proposed that a kind of novel Au-Se NPF.With Au- SNPF is compared, and Au-Se NPF show better thermodynamic stability and anti-interference ability.

2. the present invention can effectively avoid intracellular high-level biological thiol from drawing using the biosensor of Au-Se bond reconstructions The distortion of the testing result risen realizes intracellular high-fidelity imaging, and has higher selectivity and stability.

3. the biosensor based on golden selenium key prepared by the present invention have preferably anti-GSH interference performances (mM Grade), and better fidelity is shown in imaging process in physiological conditions.

Description of the drawings

The accompanying drawings which form a part of this application are used for providing further understanding of the present application, and the application's shows Meaning property embodiment and its explanation do not constitute the improper restriction to the application for explaining the application.

Fig. 1 is transmission electron microscope (TEM) phenogram of biosensor prepared by embodiment 1；

Fig. 2 is the uv absorption spectra of biosensor prepared by embodiment 1；

Fig. 3 is that the sepectrophotofluorometer of embodiment 1 carries out spectrum, a Au-Se, b Au-S；

Fig. 4 is the Thermodynamically stable linearity curve of embodiment 1, a Au-Se, b Au-S；

Fig. 5 is transmission electron microscope (TEM) phenogram of biosensor prepared by embodiment 2, and a is that Au NPs, b are Based on the biosensor of golden selenium key, c is the biosensor based on golden sulfide linkage；

Fig. 6 is the uv absorption spectra of biosensor prepared by embodiment 2；

Fig. 7 is that the sepectrophotofluorometer of embodiment 2 carries out spectrum, a Au-Se, b Au-S；

Fig. 8 is the fluorescence intensity curves that the biosensor of the preparation of embodiment 2 changes over time；

Fig. 9 is the fluorescence intensity curves that the biosensor of the preparation of embodiment 2 varies with temperature；

Figure 10 is the fluorescence intensity curves that GSH influences the biosensor of the preparation of embodiment 2, and a Au-Se, b are Au-S；

Figure 11 is the fluorescence intensity column diagram that the biosensor of the preparation of embodiment 2 changes with pH；

Figure 12 is fluorescence curve of the time to the biosensor and MMP-2 responses of the preparation of embodiment 2；

Figure 13 is fluorescence curves of the GSH to the biosensor and MMP-2 responses of the preparation of embodiment 2；

Figure 14 is fluorescence curves of the GSH and MMP-2 to biosensor；

Figure 15 is fluorescence curve of the inhibitor to biosensor and MMP-2 responses；

Figure 16 is the block diagram of influence of the different time biosensor to cell activity；

Figure 17 is the result phenogram that sulfydryl substance removes experiment, and a is Au-Se fluidic cell figures, and b is the quantization figure of a, C is Au-S fluidic cell figures, and d is the quantization figure of c；

Figure 18 be phenogram of the biosensor in cell with the response of MMP-2, a be Au-Se in different cell lines Total focused view, b be a quantization figure, c be added inhibitor after Au-Se total focused view, d for c quantization figure.

Specific implementation mode

It is noted that described further below be all exemplary, it is intended to provide further instruction to the application.Unless another It indicates, all technical and scientific terms used herein has usual with the application person of an ordinary skill in the technical field The identical meanings of understanding.

It should be noted that term used herein above is merely to describe specific implementation mode, and be not intended to restricted root According to the illustrative embodiments of the application.As used herein, unless the context clearly indicates otherwise, otherwise singulative It is also intended to include plural form, additionally, it should be understood that, when in the present specification using term "comprising" and/or " packet Include " when, indicate existing characteristics, step, operation, device, component and/or combination thereof.

As background technology is introduced, exist in the prior art that Au-S keys are unstable in the cell to cause biological thiol to draw The deficiency of testing result distortion is played, in order to solve technical problem as above, present applicant proposes a kind of biologies based on golden selenium key Sensor and preparation method.

A kind of a kind of application of the embodiment of the application there is provided golden selenium key in biosensor, biosensor The golden sulfide linkage that middle sulfydryl (- SH) is formed with gold nano grain replaces with the golden selenium that selenol group (- SeH) is formed with gold nano grain Key.

In traditional technology generally use Au-S covalent bonds (golden sulfide linkage or Au-S keys) by biomolecule and gold nano grain into Row combines and prepares biosensor, is found in the research process of present inventor, the biology obtained in this way Sensor can lead to the distortion of testing result during detection.It is sent out after the reason of further research testing result is distorted Existing, the concentration in biological cell there are biological thiol is higher, and the essence of Au-S keys is a kind of covalent bond, and stability is poor, makes It obtains biomolecule to be easy to be replaced by intracellular biological thiol, so as to cause the distortion of testing result.So the hair of the application A person of good sense replaces Au-S keys with the higher gold selenium key (Au-Se keys) of stability, finds to divide gold nano grain and biology with Au-Se keys Son combines the biosensor formed to have better sensing capabilities, and caused by capable of effectively avoiding intracellular high concentration mercaptan The distortion of signal is detected, and realizes intracellular high-fidelity imaging.

Wherein, sulfydryl can be modified to selenol group, such as seleno by the incorporation way of selenol group by existing method Cysteine.

The another embodiment of the application provides a kind of biosensor, includes the biology with recognition group point Son and gold nano grain, the biomolecule with recognition group contain selenol group, the selenol group and gold nano Particle shape makes biomolecule and gold nano grain with recognition group combine, each gold nano grain and at least one at golden selenium key A biomolecule with recognition group combines.

Herein described recognition group, which is fluorescence sense, Raman sensing, light sound sensor or electrochemical sensing, to be identified Group or molecule.

It can be with bibliography C.Jenny Mu, David A.LaVan, Robert S.Langer, and in fluorescence sense Bruce R.Zetter.Self-Assembled Gold Nanoparticle Molecular Probes for Detecting Proteolytic Activity In Vivo.Acs Nano 2010,4(3),1511–1520。

It can be with bibliography YunWei Charles Cao, Rongchao Jin, Chad in Raman sensing A.Mirkin.Nanoparticles with Raman Spectroscopic Fingerprints for DNA and RNA Detection.Science 297(5586),1536-1540。

It can be with bibliography Yijing Liu, Jie He, Kuikun Yang, Chenglin Yi, Yi in light sound sensor Liu,Liming Nie,Niveen M.Khashab,Xiaoyuan Chen,and Zhihong Nie.Folding Up of Gold Nanoparticle Strings into Plasmonic Vesicles for Enhanced Photoacoustic Imaging.Angew.Chem.2015,127,16035–16038。

With bibliography Shusheng Zhang, Jianping Xia, and Xuemei in electrochemical sensing Li.Electrochemical Biosensor for Detection of Adenosine Based on Structure- Switching Aptamer and Amplification with Reporter Probe DNA Modified Au Nanoparticles.Anal.Chem.2008,80,8382–8388。

Above with reference to the preparation process that document is the biosensor based on golden sulfide linkage, those skilled in the art can basis The prior art is by sulfydryl modification for selenol group so that golden sulfide linkage is replaced with golden selenium key, to be prepared into the life based on golden selenium key Object sensor.

The application the third embodiment there is provided a kind of above-mentioned biosensor fluorescence sense, Raman sensing, light Application in sound sensing and electrochemical sensing field.

A kind of exemplary embodiment of the application, provides a kind of biosensor based on golden selenium key, including fluorescein, Peptide chain and gold nano grain, the fluorescein modify the N-terminal in peptide chain, and the C-terminal amino acid of the peptide chain contains exposed selenol Group, the gold nano grain form golden selenium key and peptide chain combination by selenol group, each gold nano grain with it is at least one Peptide chain combination.

Preferably, the amino acid sequence of peptide chain is Asp-Gly-Pro-Leu-Gly-Val-Arg-Gly-Cys (SEQ ID NO.1).Wherein, the Cys is seleno cysteine.

It is further preferred that Cys is the C-terminal of peptide chain.

Preferably, the size of the gold nano grain is 13 ± 2nm.

Preferably, each gold nano grain and 10~300 peptide chain combinations.

This application provides a kind of preparation methods of the above-mentioned biosensor based on golden selenium key, and N-terminal is modified with fluorescence The peptide chain of element is added into the dispersion liquid of gold nano grain, can be obtained based on golden selenium key after being protected from light stirring reaction in 36~72 hours Biosensor；Wherein, peptide chain C-terminal amino acid contains exposed selenol group.

Preferably, the solution that surfactant is added into the dispersion liquid of gold nano grain obtains mixed liquor, adds N-terminal It is modified with the solution of the peptide chain of fluorescein, can be obtained the bio-sensing based on golden selenium key after being protected from light stirring reaction in 36~72 hours Device.

It is further preferred that the surfactant is lauryl sodium sulfate (SDS).Add the solution of surfactant Concentration to surfactant in mixed liquor reaches 1% (quality).N-terminal is added after acquisition mixed liquor after 30 ± 5min of stirring to repair It is decorated with the solution of the peptide chain of fluorescein.

Preferably, a concentration of 3 ± 0.1nM of the dispersion liquid of the gold nano grain.Wherein, nM is expressed as nmol/L.

In order to obtain the pure biosensor based on golden selenium key, the application is preferred, and two kinds after reaction are molten Liquid discards supernatant liquid by centrifugation (14000rpm, 20min) processing, and precipitation is re-dissolved in secondary ultra-pure water, continues Centrifugation dissolving operation, centrifugation dissolving operating process are handled three times.

This application provides a kind of above-mentioned biosensors based on golden selenium key in detection matrix metalloproteinase (MMP) Application.The matrix metalloproteinase is matrix metalloproteinase 2 (MMP-2).Detecting the application of matrix metalloproteinase is For the purpose of the Clinics and Practices of non-disease.

Preferably, each gold nano grain and 47 ± 5 peptide chain combinations.

In order to enable those skilled in the art can clearly understand the technical solution of the application, below with reference to tool The technical solution of the application is described in detail in the embodiment of body.

Reagent：Gold chloride (HAuCl₄·4H₂O, 99.99%), sodium citrate (C₆H₅Na₃O₇·2H₂O), dodecyl sulphur Sour sodium (Sodium Dodecylsulfate, SDS), Tris buffer solutions, physiological buffered solution PBS, beta -mercaptoethanol, Brij35 etc. is purchased from Shanghai chemical company of Chinese Medicine group.Cysteine (Cys), selenocystine (CysSe) 2, gluathione Peptide (GSH), 3- (4,5- dimethylthiazoles -2) -2,5- diphenyltetrazolium bromide bromides (MTT), DAPI etc. are purchased from Sigma ChemicalCompany sigma chemistry reagents Co., Ltd；Matrix metalloproteinase 2, collagen dive zymoexciter, it is 1640 thin Born of the same parents' culture medium, DMEM cell culture mediums, antibiotic-mycillin, trypsase, fetal calf serum FBS etc. are purchased from Jinan Bao Saisheng Object Science and Technology Ltd.；Human normal hepatocyte (HL-7702) and liver cancer cells (HepG2) and breast cancer cell (MCF-7) purchase In Institute Of Biochemistry And Cell Biology, Shanghai Institutes For Biological Sciences, Chinese Academy Of Sciences' cell bank.Experiment all kinds of examinations used Agent is the pure rank of analysis, and no special instruction is not specially treated.Experiment water used is bis- ultra-pure water (18.2M of Mill-Q Ω·cm^-1)。

The sequence of use is as follows：

FITC-Asp-Gly-Pro-Leu-Gly-Val-Arg-Gly-Cys, the wherein-SH of Cys are exposed,

FITC-Asp-Gly-Pro-Leu-Gly-Val-Arg-Gly- { Se-Cys }, wherein-the SeH of Se-Cys is exposed.

The N-terminal of two peptide chains all connects FITC.Purchased from Ningbo health shellfish biochemistry Co., Ltd.

The synthesis of nanogold

The synthesis of nanogold is according to classical Frens methods.Glass apparatus used in experiment is located as follows first Reason：First use chloroazotic acid (dense HCl and dense HNO₃Volume ratio 3:1) it impregnates 2 hours, place into alkali cylinder and impregnate ten minutes or so.It washes With secondary ultrapure water three times or more after net, it is positioned in baking oven and is dried for standby for 120 DEG C.The 70mL mass fractions (m/m) are taken to be 0.01% HAuCl₄Aqueous solution is in round-bottomed flask, and heating stirring to solution boils under the action of magnetic stirring apparatus, at this time Solution is yellow.Later in stirring boiling process, the sodium citrate that 3.5mL mass fractions are 1% is added into round-bottomed flask Solution aqueous solution, solution slowly become claret, continue to keep under fluidized state, stir about 20min turns off magnetic agitation later The heating function of device continues to stir, and waits for that solution is cooled to room temperature the power supply for turning off magnetic stirring apparatus, removes round-bottomed flask, will close At nano-Au solution processing is filtered by 0.45 μM of filter membrane, pour into clean 100mL serum bottles, be stored in later Storing solution is used as in 4 DEG C of refrigerators.The size pattern of the nano Au particle of synthesis can be by transmission electron microscope (TEM) into property It is analyzed and characterized.A concentration of 3nM of AuNPs storing solutions.

Embodiment 1

Biosensor (Au-Se NPF) based on golden selenium key and the biosensor (Au-S NPF) based on golden sulfide linkage Synthesis

Take the AuNPs solution of the 13nm of preparation in clean 10mL serum bottles, in whipping process into each serum bottle It is slowly added to Surfactant SDS (SDS) solution that mass fraction (m/m) is 10%, ensures that the end of SDS is dense Degree reaches 0.1%, continues stir about 30 minutes, then be slowly added dropwise into serum bottle various concentration two kinds of peptide chains it is water-soluble Liquid, 270rpm is protected from light stirring 48 hours under room temperature, and reaction was completed.By after reaction two kinds of solution by centrifugation (14000rpm, 20min) processing discards supernatant liquid, and precipitation is re-dissolved in secondary ultra-pure water, continues centrifugation dissolving operation, the process into Row is handled three times.Two kinds of biosensors of the Au-S finally obtained and Au-Se are dispersed in the PBS (10mM) of pH=7.4, are used Masking foil, which is wrapped, to be protected from light, and Au-S and Au-Se is for use as biosensor storing solution on label.Biosensor storing solution it is dense Degree can be measured by ultraviolet specrophotometer.Take two kinds of the AuNPs solution synthesized in right amount, Au-S and Au-Se bio-sensings Device storing solution is added separately in absorption cell, and absorbance is obtained using ultraviolet specrophotometer.It is dense according to known AuNPs solution Degree and the AuNPs of synthesis can calculate two kinds of biologies of Au-S and Au-Se and pass in the quenching absorptivity ε that wavelength is 524nm The concentration of sensor storing solution.Experiment later can be by Tris buffer solutions by two kinds of biosensors of Au-S and Au-Se Storing solution is diluted to required concentration, and if not being specifically noted, biosensor solution is all 1nM when in use under normal circumstances.

Two kinds of nano biological sensor groups load onto the determination of peptide chain number

It takes two kinds of nano biological sensor solution of appropriate 1nM to be added in clean 8mL serum bottles, then adds into serum bottle Enter mercaptoethanol (ME), to ensure that two kinds of peptide chains react completely, the amount for the mercaptoethanol being added is needed to be passed relative to two kinds of biologies Sensor is excessive, makes the final concentration of 20nM of mercaptoethanol in Au-S NPF solution, and the end of mercaptoethanol is dense in Au-Se NPF Degree is 80nM.In order to make mercaptoethanol fully compete be supported on nano Au particle two kinds of peptide chains as far as possible, two kinds 270rpm is protected from light stirring 12 hours to reaction solution at normal temperatures, stops reaction.Two kinds of solution after reaction are subjected to centrifugal treating (14000rpm, 30min), it is therefore an objective to the two kinds of peptide chains and nano-particle point of the FITC labels competed by mercaptoethanol It opens, supernatant liquor is taken to preserve, by 920 type Edinburgh FLS sepectrophotofluorometers, fluorescence spectrum is carried out to supernatant liquor Scanning experiment, obtain the fluorescence intensity size of supernatant liquor.The peptide chain of FITC labels selects the exciting light of 490nm wavelength The fluorescence intensity in 498nm to 650nm ranges in emission spectrum is collected in excitation.To obtain standard curve, by known concentration Two kinds of peptide chains of FITC labels are diluted to various concentration and prepare 7 samples respectively, keep with above-mentioned experiment condition unanimously (it is identical from Sub- intensity, identical pH, identical mercaptoethanol concentration etc.), its fluorescence intensity level is measured, the corresponding fluorescence of two kinds of peptide chains is drawn out Curve.It finds and is measured with before divided by the identical fluorescence intensity level of the supernatant liquor of corresponding concentration on standard curve, it will Fluorescence intensity is converted to the concentration of corresponding peptide chain, with the concentration of peptide chain divided by the concentration of corresponding AuNPs, can obtain every The quantity of the peptide chain of a nanogold particle load.

The absorption spectromtry of nanogold, Au-Se NPF and Au-S NPF

AuNPs solution, each 200 μ L of Au-Se NPF and Au-S NPF storing solutions is taken to be added in 96 clean orifice plates respectively, The scanning of ultra-violet absorption spectrum is carried out using microplate reader, scanning range selection is wavelength 200nm to 700nm.

Stability influence of the temperature to two kinds of biosensors itself of Au-S and Au-Se

It pipettes each 200 μ L of Au-Se NPF and Au-S NPF (1nM) to be added in 2mL EP pipes, 0- is incubated at 37 DEG C 12h, after biosensor solution is poured into micro ware.Spectral scan is carried out by sepectrophotofluorometer, is collected in λ Fluorescence intensity change situation at ex/ λ em=490/520nm, slit are set as 2.5nm.To ensure the accurate fixed of experimental result, Two kinds of biosensor samples at least need to do 3 parallel laboratory tests.

It pipettes each 200 μ L of Au-Se NPF and Au-S NPF (1nM) to be added in 2mL EP pipes, in condition of different temperatures (20 DEG C, 30 DEG C, 40 DEG C, 50 DEG C, 60 DEG C, 70 DEG C, 80 DEG C) under be incubated 5min, after biosensor solution poured into micro ware In.Spectral scan is carried out by sepectrophotofluorometer, collects the fluorescence intensity change feelings at λ ex/ λ em=490/520nm Condition, slit are set as 2.5nm.To ensure the accurate fixed of experimental result, two kinds of biosensor samples, which at least need to do 3 times, puts down Row experiment.

Influences of the 5mM GSH to two kinds of biosensors itself of Au-S and Au-Se

In the case where simulating physiological condition, influences of the 5mM GSH to Au-Se NPF and Au-S NPF itself is measured.It weighs first 0.0609g GSH solid powders are dissolved in bis- ultra-pure waters of 4mL, are configured to the GSH storing solutions of 50mM.By synthesis Au-Se NPF and Au-S NPF storing solutions are diluted with PBS buffer solutions (10nM, pH=7.4), make its final concentration be 1nM.Each 200 μ L of Au-Se NPF and Au-S NPF that control group pipettes final concentration of 1nM are added in 2mL EP pipes.Experimental group Each 180 μ L of Au-Se NPF and Au-S NPF for pipetting a concentration of 1nM add 20 μ L GSH storing solutions.Reaction solution needs abundant Mixing is incubated 0,2,4,6,8,10,12 hour respectively at 37 DEG C, after the mixed solution after reaction is poured into micro ware. Spectral scan is carried out by sepectrophotofluorometer, collects the fluorescence intensity change situation at λ ex/ λ em=490/520nm, Slit is set as 2.5nm.For ensure experimental result it is accurate calmly, two kinds of biosensor samples at least need to do 3 times parallel Experiment.

Sulfydryl substance removes experiment

Au-Se NPF and Au-S the NPF storing solutions of synthesis are diluted with cell culture fluid, keep its final concentration equal For 1nM.By MCF-7 cell inoculations in four capsules, adherent growth for 24 hours after, tested.Experimental group is first incubated with 500 μM of NEM Hatching cell 20min, control group are not processed.Two kinds of lifes of Au-S and Au-Se of final concentration of 1nM are added into culture dish again later After being incubated 4h at 37 DEG C, by cell dissociation, 150 μ L PBS (nothings are added after centrifugation (1000rpm, 3min) three times in object sensor Ca²⁺And Mg²⁺), the signal of FITC is acquired with flow cytometer.This experiment equally at least carries out the parallel laboratory test above three times, Then carry out the analysis of experimental result.

As a result with analysis

The synthesis of Au NPs, Au-Se NPF and Au-S NPF and characterization

Fig. 1 is respectively the transmission electron microscope of the Au NPs prepared and Au-Se NPF and the Au-S NPF of synthesis (TEM) phenogram.It can be seen from the figure that the Au NPs particle sizes of synthesis are uniform, diameter is average in 13nm or so, and point It dissipates uniformly, the edge of particle is apparent from.The size of Au-Se NPF and the Au-S NPF of synthesis are compared with Au NPs without too big Variation.Fig. 2 is the uv absorption spectra of Au NPs and Au-Se NPF and Au-S NPF, it can be seen that the maximum of Au NPs Absorption peak is modified after peptide chain, the maximum absorption band of Au-Se NPF and Au-S NPF are sent out compared with Au NPs in 520nm or so Small red shift is given birth to, near 524nm, it was demonstrated that the peptide chain with FITC labels has successfully been modified on the surfaces Au NPs. The standard curve between peptide chain concentration and fluorescence intensity is established, and two kinds of peptide chains for calculating FITC labels are supported on individually respectively Number on nano Au particle.Each Au NPs are modified on two kinds of biosensors that the peptide chain of various concentration synthesizes two Kind peptide chain number is as shown in table 1.In order to ensure the accurate reliability of next contrast experiment, two kinds of each Au of nano platform Two kinds of peptide chain numbers that NPs is modified are as equal as possible (107 ± 2).

Table 1

Influences of the GSH to Au-Se NPF and Au-S NPF

In the case where simulating physiological condition, influences of the 5mM GSH to Au-Se NPF and Au-S NPF, Au-Se NPF and Au-S NPF concentration is 1nM.Au-Se NPF and Au-S NPF are not added with respectively or additional 5mM GSH storing solutions, reaction solution are sufficiently mixed It is incubated respectively 0,2,4,6,8,10,12 hour at 37 DEG C afterwards, spectral scan is carried out by sepectrophotofluorometer, as a result such as Fig. 3 It is shown, it can be seen that before and after GSH is added, Au-Se NPF change in fluorescence unobvious, and Au-S NPF are outside plus after GSH Fluorescence is remarkably reinforced (12h increases 7.9 times).The experimental verification is in the presence of high concentration GSH, with traditional Au-S NPF phases Than Au-Se NPF have higher stability.Meanwhile the thermodynamic stability of Au-Se NPF and Au-S NPF are had studied, point Au-Se NPF and Au-S NPF are not incubated 0~12 hour or are incubated respectively at 10~80 DEG C 5 minutes at 37 DEG C respectively, As shown in Figure 4, it can be seen that compared with Au-S NPF, Au-Se NPF have rear better thermodynamic stability.

The interference of intracellular biological mercaptan

Au-Se NPF and the Au-S NPF of synthesis are diluted with cell culture fluid, it is 1nM to make its final concentration. By MCF-7 cell inoculations in four capsules, adherent growth for 24 hours after, tested.Experimental group is first incubated with 500 μM of NEM thin Born of the same parents 20min, control group are not processed.Two kinds of biologies of Au-S and Au-Se that final concentration of 1nM is added into culture dish again later pass After being incubated 4h at 37 DEG C, by cell dissociation, 150 μ L PBS (no Ca are added after centrifugation (500rpm, 2min) three times in sensor²⁺With Mg²⁺), the signal of FITC is acquired with flow cytometer, is as a result illustrated in fig. 5 shown below, before and after removing biological thiol with NEM, Au-Se The intensity of cellular fluorescence that NPF is incubated is almost without any variation, and the cell that Au-SNPF is incubated, before removing biological thiol There are one the fluorescence signals being remarkably reinforced to generate.Thus it verifies compared with traditional Au-S NPF, Au-Se NPF have in the cell There are better stability and higher antibiont mercaptan interference performance.

Embodiment 2

In order to further verify Au-Se NPF in the practicability of sensory field, it is prepared for a kind of Au-Se biosensors use In the detection of MMP-2.

Synthesis (Au-S-peptide-FITC and the Au-Se-peptide- of two kinds of biosensors of Au-S and Au-Se FITC)

Take the AuNPs solution of the 13nm prepared before in clean 10mL serum bottles, to each serum in whipping process It is slowly added to Surfactant SDS (SDS) solution that mass fraction (m/m) is 10% in bottle, ensures SDS's Final concentration reaches 0.1%, continues stir about 30 minutes, then be slowly added dropwise into serum bottle two kinds of peptide chains of various concentration Aqueous solution (150,300,360,450,600and 900nM), 270rpm is protected from light stirring 48 hours under room temperature, and reaction was completed.It will be anti- Two kinds of solution after answering discard supernatant liquid by centrifugation (14000rpm, 20min) processing, and precipitation is re-dissolved in secondary ultra-pure water In, continue centrifugation dissolving operation, which is handled three times.Two kinds of biologies of the Au-S finally obtained and Au-Se are passed Sensor is dispersed in the Tris (10mM) of pH=7.4, is wrapped and is protected from light with masking foil, and Au-S and Au-Se is passed as biology on label Sensor storing solution is for use.The concentration of biosensor storing solution can be measured by ultraviolet specrophotometer.Take appropriate synthesis AuNPs solution, two kinds of biosensor storing solutions of Au-S and Au-Se be added separately in absorption cell, utilize ultraviolet spectrometry light Degree meter obtains absorbance.According to known AuNPs solution concentrations and the AuNPs of synthesis in the quenching extinction that wavelength is 524nm Coefficient ε, so that it may to calculate the concentration of two kinds of biosensor storing solutions of Au-S and Au-Se.Experiment later can pass through The storing solution of two kinds of biosensors of Au-S and Au-Se is diluted to required concentration by Tris buffer solutions, if not being specifically noted, Biosensor solution is all 1nM when in use under normal circumstances.Two kinds of nano biological sensor groups load onto peptide chain number really It is fixed

It takes two kinds of nano biological sensor solution of appropriate 1nM to be added in clean 8mL serum bottles, then adds into serum bottle Enter mercaptoethanol (ME), to ensure that two kinds of peptide chains react completely, the amount for the mercaptoethanol being added is needed to be passed relative to two kinds of biologies Sensor is excessive, makes the final concentration of 20nM of mercaptoethanol in golden sulphur biosensor solution, mercapto in golden selenium biosensor The final concentration of 80nM of base ethyl alcohol.In order to make mercaptoethanol fully compete be supported on nano Au particle two as far as possible Kind peptide chain, 270rpm is protected from light stirring 12 hours to two kinds of reaction solutions at normal temperatures, stops reaction.Two kinds of solution after reaction are carried out Centrifugal treating (14000rpm, 30min), it is therefore an objective to the two kinds of peptide chains and nanometer of the FITC labels competed by mercaptoethanol Particle separates, and supernatant liquor is taken to preserve, and by 920 type Edinburgh FLS sepectrophotofluorometers, is carried out to supernatant liquor glimmering The scanning of light spectrum is tested, and the fluorescence intensity size of supernatant liquor is obtained.The peptide chain of FITC labels selects swashing for 490nm wavelength It shines to excite, collects the fluorescence intensity in 498nm to 650nm ranges in emission spectrum.It, will be known dense to obtain standard curve Two kinds of peptide chains of the FITC labels of degree are diluted to various concentration and prepare 7 samples respectively, keep (phase consistent with above-mentioned experiment condition Homo-ion intensity, identical pH, identical mercaptoethanol concentration etc.), its fluorescence intensity level is measured, it is corresponding to draw out two kinds of peptide chains Fluorescence curve.It finds and is measured with before divided by the identical fluorescence intensity of the supernatant liquor of corresponding concentration on standard curve Fluorescence intensity, is converted to the concentration of corresponding peptide chain, with the concentration of peptide chain divided by the concentration of corresponding AuNPs by value, so that it may To obtain the quantity of the peptide chain of each nanogold particle load.

The absorption spectromtry of two kinds of nanogold, Au-S and Au-Se biosensors

AuNPs solution, Au-S and each 200 μ L of two kinds of biosensor storing solutions of Au-Se is taken to be added to clean 96 respectively In orifice plate, the scanning of ultra-violet absorption spectrum is carried out using microplate reader, scanning range selection is wavelength 200nm to 700nm.Au-S With the detection of the fluorescence spectrum of two kinds of biosensors of Au-Se

In the case where simulating physiological condition, all fluorescence is carried out by 920 type sepectrophotofluorometers of Edinburgh FLS The scanning of spectrum.Steps are as follows for specific experiment：When preparing sample, first by two kinds of biosensor storages of the Au-S of synthesis and Au-Se Standby liquid is diluted with Tris buffer solutions (10nM, pH=7.4), and it is 1nM to make its final concentration.Determinand is added, is filled Divide after mixing, is added in constant ware or micro ware after 37 DEG C of incubation 30min.Spectrum is carried out by sepectrophotofluorometer Scanning, collects the fluorescence intensity change situation at λ ex/ λ em=490/520nm, and slit is set as 2.5nm.Time is to Au-S With the stability influence of two kinds of biosensors of Au-Se itself

In the case where simulating physiological condition, influence of the minute to two kinds of biosensors itself of Au-S and Au-Se.It will synthesis Two kinds of biosensor storing solutions of Au-S and Au-Se be diluted with Tris buffer solutions (10nM, pH=7.4), make it Final concentration is 1nM.It pipettes Au-S and each 200 μ L of two kinds of biosensors of Au-Se is added in 2mL EP pipes, at 37 DEG C respectively Be incubated 0,2,4,6,8,10,12 hour, after biosensor solution is poured into micro ware.Pass through sepectrophotofluorometer Spectral scan is carried out, the fluorescence intensity change situation at λ ex/ λ em=490/520nm is collected, slit is set as 2.5nm.For Ensure the accurate fixed of experimental result, two kinds of biosensor samples at least need to do 3 parallel laboratory tests.

In the case where simulating physiological condition, influence of the measuring temperature to two kinds of biosensors itself of Au-S and Au-Se.It will synthesis Two kinds of biosensor storing solutions of Au-S and Au-Se be diluted with Tris buffer solutions (10nM, pH=7.4), make it Final concentration is 1nM.It pipettes Au-S and each 200 μ L of two kinds of biosensors of Au-Se is added in 2mL EP pipes, in different temperatures Be incubated 5min under condition (20 DEG C, 30 DEG C, 40 DEG C, 50 DEG C, 60 DEG C, 70 DEG C, 80 DEG C), after biosensor solution is poured into In micro ware.Spectral scan is carried out by sepectrophotofluorometer, collects the fluorescence intensity at λ ex/ λ em=490/520nm Situation of change, slit are set as 2.5nm.To ensure the accurate fixed of experimental result, two kinds of biosensor samples at least need to do 3 Secondary parallel laboratory test.

Influences of the 5mM GSH to two kinds of biosensors itself of Au-S and Au-Se

In the case where simulating physiological condition, influences of the 5mM GSH to two kinds of biosensors itself of Au-S and Au-Se is measured.It is first 0.0609g GSH solid powders are first weighed, is dissolved in bis- ultra-pure waters of 4mL, is configured to the GSH storing solutions of 50mM.It will Two kinds of biosensor storing solutions of Au-S and Au-Se of synthesis are diluted with Tris buffer solutions (10nM, pH=7.4), It is 1nM to make its final concentration.Each 200 μ L of two kinds of biosensors of Au-S and Au-Se that control group pipettes final concentration of 1nM are added Into 2mL EP pipes.Each 180 μ L of two kinds of biosensors of Au-S and Au-Se that experimental group pipettes a concentration of 1nM add 20 μ L GSH storing solutions.Reaction solution needs be sufficiently mixed, be incubated respectively at 37 DEG C 0,2,4,6,8,10,12 hour, after will reaction after Mixed solution pour into micro ware.Spectral scan is carried out by sepectrophotofluorometer, is collected in λ ex/ λ em=490/ Fluorescence intensity change situation at 520nm, slit are set as 2.5nm.To ensure the accurate fixed of experimental result, two kinds of bio-sensings Device sample at least needs to do 3 parallel laboratory tests.

In addition, 5mM GSH are added into two kinds of biosensors, albumen MMP-2 (10 is added^-1μ g/mL), it incubates at 37 DEG C Educate 30min, after the mixed solution after reaction is poured into micro ware.Spectral scan is carried out by sepectrophotofluorometer, The fluorescence intensity change situation at λ ex/ λ em=490/520nm is collected, slit is set as 2.5nm.To ensure experimental result Accurate fixed, two kinds of biosensor samples at least need to do 3 parallel laboratory tests.

PH value is responded to Au-Se biosensors and MMP-2 and the influence of biosensor itself

It is all Tirs buffer solutions to test buffer solution used in clock, which determines between pH=6.0~8.2 Fluctuate the influence to Au-Se biosensors and determinand MMP-2 response conditions, Au-Se biosensors itself fluorescence.It will close At Au-Se biosensors storing solution with different pH value (pH=6.2,6.4,6.6,6.8,7.0,7.2,7.4,7.6,7.8, 8.0) Tris buffer solutions are diluted, and make its final concentration of 1nM.A series of samples is configured, the difference of certain volume is pipetted The Au-Se biosensors of the final concentration of 1nM of pH value are added in 2mL EP pipes, are added into biosensor solution to be measured Object (matrix metalloproteinase 2 (controlling its final concentration of 0.1 μ g/mL) activated) is sufficiently mixed uniformly, at 37 DEG C respectively Be incubated 30min, after the mixed solution after reaction is poured into micro ware.Spectrum is carried out by sepectrophotofluorometer to sweep It retouches, measures fluorescence intensity change situation of its fluorescence intensity level with the situation of change collection of P at λ ex/ λ em=490/520nm, Slit is set as 2.5nm.For ensure experimental result it is accurate calmly, each biosensor sample at least needs to do 3 times parallel Experiment.

The dynamic experiment of Au-Se biosensors

In the case where simulating physiological condition, influence of the minute to Au-Se biosensors and MMP-2 responses.By synthesis Au-Se biosensors storing solution is diluted with Tris buffer solutions (10nM, pH=7.4), makes its final concentration of 1nM.Match A series of samples is set, the Au-Se biosensors for pipetting the final concentration of 1nM of certain volume are added in 2mL EP pipes, Xiang Sheng Determinand (matrix metalloproteinase 2 (controlling its final concentration of 0.1 μ g/mL) activated) is added in object sensor solution, Be sufficiently mixed uniformly, be incubated respectively at 37 DEG C 0,2.5,5,10,15,20,25,30,35 minute, after by the mixing after reaction Solution pours into micro ware.Spectral scan is carried out by sepectrophotofluorometer, its fluorescence intensity level is measured and changes with time Situation collects the fluorescence intensity change situation at λ ex/ λ em=490/520nm, and slit is set as 2.5nm.To ensure experiment knot The accurate of fruit is determined, and each biosensor sample at least needs to do 3 parallel laboratory tests.Au-Se biosensors and matrix gold The response of Proteases 2

In the case where simulating physiological condition, the influence of Au-Se biosensors and MMP-2 responses is measured.The Au-Se of synthesis is given birth to Object sensor storing solution is diluted with Tris buffer solutions (10nM, pH=7.4), makes its final concentration of 1nM.Pipette certain body The Au-Se biosensors of long-pending final concentration of 1nM are added in 2mL EP pipes, are added into biosensor solution to be measured The object ----matrix metalloproteinase 2 that has activated (control its final concentration of 0.1,0.01,0.001,10^-4、10^-5、10^-6、10^-7 μ g/mL), be sufficiently mixed uniformly, be incubated 30 minutes at 37 DEG C, after the mixed solution after reaction is poured into micro ware.It is logical It crosses sepectrophotofluorometer and carries out spectral scan, measure its fluorescence intensity level and change with time situation collection in λ ex/ λ em= Fluorescence intensity change situation at 490/520nm, slit are set as 2.5nm.To ensure the accurate fixed of experimental result, each biology Sample sensor at least needs to do 3 parallel laboratory tests.

Influence of the inhibitor to Au-Se biosensors and matrix metalloproteinase 2 response

In the case where simulating physiological condition, influence of the inhibitor to Au-Se biosensors and MMP-2 responses is measured.It will synthesis Au-Se biosensors storing solution be diluted with Tris buffer solutions (10nM, pH=7.4), make its final concentration of 1nM. Experiment is divided into three groups, and the Au-Se biosensors for pipetting the final concentration of 1nM of certain volume are added in 2mL EP pipes, control Group is biosensor blank, and one group of experimental group is that the matrix metalloproteinase activated is added into biosensor solution 2, after another group is added protein inhibitor Marimastat incubations 12 hours on this basis, three groups of samples are incubated at 37 DEG C Educate 30 minutes, after the mixed solution after reaction is poured into micro ware.Spectral scan is carried out by sepectrophotofluorometer, It measures its fluorescence intensity level situation that changes with time and collects fluorescence intensity change situation at λ ex/ λ em=490/520nm, Slit is set as 2.5nm.For ensure experimental result it is accurate calmly, each biosensor sample at least needs to do 3 times parallel Experiment.

The biosystem of Au-Se biosensors is tested

Culture cell key step includes recovering, passing on, freezing.Super-clean bench operates, and all items carry out disinfection place Reason, wherein the ratio for preparing cells frozen storing liquid is：7 (culture mediums)：2 (serum)：1(DMSO).

MTT experiment

Experimental method：

(1) cell culture is carried out according to cell culture method.Points for attention：Hepatocellular carcinoma H22 all supplements 10% tire ox blood 1% antibiotics penicillin, the streptomysin of cleer and peaceful 100U/mL, incubator environment are 37 DEG C, contain the air of 5% carbon dioxide；Carefully Born of the same parents, which digest, notices that the time avoids digestion time is long from leading to cell death；The PBS lifes of 200 μ L are added in the hole of 96 orifice plate outmost turns Manage buffer solution；Ensured 1 × 10 with the concentration of cell counting board cell count⁶/ mL or so, it is ensured that suitable cell concentration.

(2) same concentrations are incubated the MTT experiment of different time：Culture medium is sucked out, point three groups of experiments, nanogold, Au-S Biosensor and Au-Se biosensors, every group of biosensor are diluted with culture solution, make its final concentration 1nM.To Three kinds of solution of 100 μ L are added in each hole, is placed in incubator and is incubated 0,3,6,9,12 respectively, for 24 hours.Then unifying will be biological Sensor culture solution is sucked out, and the MTT solution (0.5mg/mL) that 100 μ L are added in each hole continues to be incubated 4 hours, purple occurs Dimethyl sulfoxide (DMSO) 150 μ L are then added in precipitation in each hole, the parallel laboratory test above three times is at least done in each experiment, really Experiment true and accurate is protected, the UV absorption at 490nm is measured using microplate reader, calculates analysis.Sulfydryl substance is removed Experiment

Two kinds of biosensor storing solutions of the Au-S of synthesis and Au-Se are diluted with cell culture fluid, its end is made Concentration is 1nM.By HepG2 cell inoculations in four capsules, adherent growth for 24 hours after, tested.Experimental group is first with 500 μ M NEM incubated cell 20min, control group are not processed.The Au-S and Au- of final concentration of 1nM is added into culture dish again later After being incubated 4h at 37 DEG C, by cell dissociation, 150 μ are added after centrifugation (1000rpm, 3min) three times in two kinds of biosensors of Se L PBS (no Ca²⁺And Mg²⁺), the signal of FITC is acquired with flow cytometer.This experiment equally at least carries out more than three times Parallel laboratory test then carries out the analysis of experimental result.

Au-Se biosensors in cell with the response of MMP-2

Normal liver cell HL-7702, hepatocellular carcinoma H22, breast cancer cell MCF-7 are seeded in the burnt ware of copolymerization first In (be added 200 μ L), it is in good condition after band cell is adherent, by the Au-Se biosensors storing solution of synthesis with 1640, DMEM culture solutions are diluted, and make its final concentration of 1nM.The Au-Se biosensors for pipetting the final concentration of 1nM of 200 μ L add Enter into the burnt ware of copolymerization, continue to be incubated 4 hours, then take out culture solution, cleans the burnt ware of copolymerization three times with Tris buffer solutions, wash Net biosensor residual.Cell is fixed in the paraformaldehyde solution incubation 20min for adding 200 μ L, is buffered with Tris The burnt ware of solution cleaning copolymerization is three times.200 μ L dyeing liquors DAPI are added later and are incubated 5min, and copolymerization is cleaned with Tris buffer solutions Burnt ware carries out laser confocal imaging three times, takes pictures and records fluorescence intensity level, this experiment equally at least carries out more than three times Parallel laboratory test, then carry out experimental result analysis.

Influence of the inhibitor to Au-Se biosensors in cell with MMP-2 responses

Hepatocellular carcinoma H22, breast cancer cell MCF-7 are seeded in the burnt ware of copolymerization first and (200 μ L are added), band cell It is in good condition after adherent, the Au-Se biosensors storing solution of synthesis is diluted with 1640, DMEM culture solutions, makes it Final concentration of 1nM.Experimental group first uses inhibitor incubated cell one hour, and control group is not processed.The end for pipetting 200 μ L later is dense Degree is that the Au-Se biosensors of 1nM are added in the burnt ware of copolymerization, continues to be incubated 4 hours, then takes out culture solution, use Tris The burnt ware of buffer solution cleaning copolymerization three times, cleans biosensor residual.The paraformaldehyde solution for adding 200 μ L is incubated Cell is fixed in 20min, and the burnt ware of copolymerization is cleaned three times with Tris buffer solutions.200 μ L dyeing liquors DAPI are added later It is incubated 5min, clean the burnt ware of copolymerization with Tris buffer solutions carries out laser confocal imaging three times, takes pictures and records fluorescence intensity Value, this experiment equally at least carry out the parallel laboratory test above three times, then carry out the analysis of experimental result.

As a result with analysis

Nanogold, the synthesis of two kinds of biosensors of Au-S and Au-Se and characterization

Two kinds of biosensors are devised according to Au-S keys and the two different bonding patterns of Au-Se keys, the one of peptide chain End connects cysteine and selenocysteine to provide sulfydryl and seleno respectively.Fig. 5 is respectively the AuNPs prepared and synthesis Two kinds of biosensors of Au-S and Au-Se transmission electron microscope (TEM) phenogram.From fig. 6 it can be seen that synthesis AuNPs particle sizes are uniform, and diameter is average in 13nm or so, and is uniformly dispersed, and the edge of particle is apparent from.The Au-S of synthesis With the size of two kinds of biosensors of Au-Se compared with AuNPs without too big variation.Fig. 6 is AuNPs and Au-S and Au- The uv absorption spectra of two kinds of biosensors of Se.It can be seen from figure 7 that the maximum absorption band of AuNPs is on the left sides 520nm The right side is modified after peptide chain, and the maximum absorption bands of two kinds of biosensors of Au-S and Au-Se has occurred small compared with AuNPs Red shift, near 524nm, it was demonstrated that the peptide chain with FITC labels has successfully been modified on the surfaces AuNPs.And absorption maximum The strength reduction at peak is cleaned multiple times this is because when carrying out centrifugal treating operation to two kinds of biosensors of Au-S and Au-Se So that nanogold loses and concentration is caused to reduce.

The concentration of two kinds of biosensors of Au-S and Au-Se can measure respective absorbance by ultraviolet specrophotometer It is calculated.By 920 type Edinburgh FLS sepectrophotofluorometers, to containing two kinds competed by mercaptoethanol The supernatant liquor of peptide chain carries out the scanning experiment of fluorescence spectrum, obtains the fluorescence intensity size of supernatant liquor.Prepare various concentration Two kinds of peptide chain solution, keep consistent with above-mentioned experiment condition (same ion intensity, identical pH, identical mercaptoethanol concentration Deng), its fluorescence intensity level is measured, the corresponding fluorescence curve of two kinds of peptide chains is drawn out.It finds on standard curve and is measured with before Supernatant liquor identical fluorescence intensity level, fluorescence intensity is converted to the concentration of corresponding peptide chain, with the concentration of peptide chain divided by The concentration of corresponding AuNPs, so that it may with obtain each nanometer into the peptide chain of particulate load quantity.The peptide chain of various concentration closes It is as shown in table 2 at two kinds of peptide chain numbers that each AuNPs is modified on the two kinds of biosensors gone out.It is next in order to ensure The accurate reliability of contrast experiment keeps two kinds of peptide chain numbers that two kinds of each AuNPs of biosensor are modified as equal as possible. Therefore it is 48 to select the nanogold of Au-S biosensors to load the number of peptide chain, and the nanogold of Au-Se biosensors is negative The number for carrying peptide chain is 47.

Table 2

The spectral quality of two kinds of biosensors of Au-S and Au-Se

In the case where simulating physiological condition, two kinds of biosensor storing solutions of the Au-S of synthesis and Au-Se are buffered with Tris Solution (10nM, pH=7.4) is diluted, and it is 1nM to make its final concentration.Pass through 920 type fluorescence spectrophotometers of Edinburgh FLS Two kinds of biosensors of photometer pair carry out the scanning of fluorescence spectrum.As can be seen that Au-S and Au-Se two from Fig. 7 a~Fig. 7 b The excitation wavelength of kind biosensor is 490nm, and launch wavelength is 520nm.Slit setting is 2.5nm, two kinds of nanometers The fluorescence intensity of biosensor itself is very low.

Stability influence of the time to two kinds of biosensors itself of Au-S and Au-Se

Two kinds of biosensor storing solutions of the Au-S of synthesis and Au-Se are used into Tris buffer solutions (10nM, pH=7.4) It is diluted, it is 1nM to make its final concentration.It is incubated respectively at 37 DEG C 0,2,4,6,8,10,12 hour.In simulation physiological condition Under, influence of the minute to two kinds of biosensors itself of Au-S and Au-Se.Spectrum is carried out by sepectrophotofluorometer to sweep It retouches, is as a result illustrated in fig. 8 shown below.Black curve represents Au-Se biosensors, and red curve represents Au-S biosensors.It can To find out, with the increase of incubation time, the fluorescence of Au-S biosensors itself gradually increases, Au-Se biosensor sheets The fluorescence of body, which there is no, to change.Compared with blank value, when being incubated 12h, the fluorescence intensity of Au-S biosensors It it is its 2.5 times, the fluorescence intensity of Au-Se biosensors is its 1.1 times.From this it can be concluded that two kinds of lifes at 37 DEG C Object sensor is incubated different time, with the extension of time, the stability of Au-S biosensors is poor, and Au-Se biologies pass Sensor is in highly stable state, compared with Au-S biosensors, with stronger stability.Temperature to Au-S and The stability influence of two kinds of biosensors of Au-Se itself

Two kinds of biosensor storing solutions of the Au-S of synthesis and Au-Se are used into Tris buffer solutions (10nM, pH=7.4) It is diluted, it is 1nM to make its final concentration, at condition of different temperatures (20 DEG C, 30 DEG C, 40 DEG C, 50 DEG C, 60 DEG C, 70 DEG C, 80 DEG C) Lower incubation 5min.In the case where simulating physiological condition, influence of the measuring temperature to two kinds of biosensors itself of Au-S and Au-Se.It is logical It crosses sepectrophotofluorometer and carries out spectral scan, be as a result illustrated in fig. 9 shown below.Red curve represents Au-S biosensors, black Curve represents Au-Se curves.It can be seen in figure 9 that with the increase of incubation temperature, the fluorescence of Au-S biosensors itself It gradually increases, the change in fluorescence of Au-Se biosensors itself is little.Compared with blank value, at 80 DEG C, Au-S bio-sensings The fluorescence intensity of device is its 3.2 times, and the fluorescence intensity of Au-Se biosensors is its 1.5 times.It follows that in difference At a temperature of two kinds of biosensors are incubated, with the raising of temperature, the stability of Au-S biosensors is poor, and Au-Se Biosensor is in very stable state, compared with Au-S biosensors, with stronger stability.

Influences of the 5mM GSH to two kinds of biosensors itself of Au-S and Au-Se

In the case where simulating physiological condition, influences of the 5mM GSH to two kinds of biosensors itself of Au-S and Au-Se is measured.It will Two kinds of biosensor storing solutions of Au-S and Au-Se of synthesis are diluted with Tris buffer solutions (10nM, pH=7.4), It is 1nM to make its final concentration.Control group is two kinds of biosensors itself of Au-S and Au-Se, and experimental group is Au-S and Au-Se two Kind biosensor distinguishes additional 20 μ L GSH storing solutions.Reaction solution is incubated 0 at 37 DEG C respectively after being sufficiently mixed, 2,4,6,8, 10,12 hours, spectral scan is carried out by sepectrophotofluorometer, is as a result illustrated in fig. 10 shown below, the left side is Au-Se bio-sensings Device, the right are Au-S biosensors.Black and red curve represent two kinds of biosensor blank, blue and green curve generation Two kinds of Table A u-S and Au-Se is acted on GSH.From, as can be seen that before and after GSH is added, Au-S biologies pass in Figure 10 a and Figure 10 b Sensor changes very greatly, and Au-Se biosensors are reacting front and back variation with GSH less.When being incubated 12 hours, with respective blank It compares, Au-S biosensors are its 4 times, and Au-Se biosensors are its 1.5 times.Thus it is concluded that, biosensor is used When being detected, Au-S biosensors can be interfered by GSH, influence the accuracy of experimental result, and Au-Se biosensors Substantially it is not interfered by GSH, there is good accuracy and stability.

In entire reaction system, pH is delaying used in experiment an important factor for influencing biosensor sensitivity Rush solution all and be Tirs buffer solutions, the part determine the fluctuation between pH=6.2~8.0 to Au-Se biosensors with The influence of determinand MMP-2 response conditions, Au-Se biosensors itself fluorescence.By the Au-Se biosensor deposits of synthesis The Tris buffer solutions of the different pH value of liquid are diluted, and make its final concentration of 1nM.A series of samples is configured, certain body is pipetted The Au-Se biosensor solution of long-pending different pH value is added MMP-2 (controlling its final concentration of 0.1 μ g/mL), fills thereto Divide and be uniformly mixed, 20min is incubated respectively at 37 DEG C, spectral scan is carried out by sepectrophotofluorometer, as a result following Figure 11 institutes Show.Black represents biosensor blank, and red represents biosensor+determinand MMP-2, it can be seen from fig. 11 that Variation all very littles that fluorescence, biosensor blank and biosensor and MMP-2 responses are detected under different pH, in pH= Fluorescence intensity highest when 7.4.In view of experiment needs to simulate physiological environment, the Tirs buffer solutions of pH=7.4 have been selected.

The dynamic experiment of Au-Se biosensors

In the case where simulating physiological condition, influence of the minute to Au-Se biosensors and MMP-2 responses.By synthesis Au-Se biosensors storing solution is diluted with Tris buffer solutions (10nM, pH=7.4), makes its final concentration of 1nM.Match A series of samples is set, the Au-Se biosensor solution of certain volume is pipetted, is added and has activated into biosensor solution Matrix metalloproteinase 2 (controlling its final concentration of 0.1 μ g/mL), be sufficiently mixed uniformly, be incubated 0 at 37 DEG C respectively, 2.5,5, 10,15,20,25,30,35 minutes, spectral scan is carried out by sepectrophotofluorometer, as a result as shown in figure 12.From Figure 12 As can be seen that with the extension in reaction time, the fluorescence intensity after biosensor is reacted with albumen gradually rises, and Reach a stable state in 30min, the time, front and back variation was little, therefore select 30min as biosensor with it is to be measured The Best Times of object reaction carry out following experiment.

Influences of the 5mM GSH to the response of two kinds of biosensors of Au-S and Au-Se and matrix metalloproteinase 2

In the case where simulating physiological condition, influences of the 5mM GSH to Au-S and Au-Se biosensors and MMP-2 responses is measured. Au-S the and Au-Se biosensors for pipetting the final concentration of 1nM of certain volume are added in 2mL EP pipes, are first added into solution Enter final concentration of 5mM GSH solution, then the matrix metalloproteinase 2 (control activated is added into biosensor solution Its final concentration of 0.1,0.01,0.001,10^-4、10^-5、10^-6、10^-7μ g/mL), it is sufficiently mixed uniformly, 30 points is incubated at 37 DEG C Clock carries out spectral scan, as a result as shown in figure 13 by sepectrophotofluorometer.Under 5mMGSH environment, passed with Au-S biologies Sensor is compared, and there are one the more obvious raised variation of fluorescence intensity, explanations after Au-Se biosensors are responded with albumen Au-Se biosensors can be very good to resist the interference effect from 5mM GSH.

In addition, 5mM GSH are added into two kinds of biosensors, albumen MMP-2 (10 is added^-1μ g/mL), it incubates at 37 DEG C Educate 30min, after the mixed solution after reaction is poured into micro ware.Spectral scan is carried out by sepectrophotofluorometer, Experimental result is as shown in figure 14.Under 5mM GSH environment, compared with Au-Se biosensors, the fluorescence of Au-S biosensors Intensity is increased, and illustrates that GSH can cause fluorogen release to send out fluorescence with Au-S keys.It is calculated according to experimental data, There are one higher signal-to-noise ratio (10.1) and a lower detection to limit (1.7ng/mL) for Au-Se biosensors tool, and Au-S The signal-to-noise ratio of biosensor is (3.9) and a lower detection limits (3.1ng/mL), illustrates Au-Se biosensors to egg A more sensitive signal can be showed in vain.

In the case where simulating physiological condition, influence of the inhibitor to Au-Se biosensors and MMP-2 responses is measured.It will synthesis Au-Se biosensors storing solution be diluted with Tris buffer solutions (10nM, pH=7.4), make its final concentration of 1nM. Experiment is divided into three groups, and the Au-Se biosensors for pipetting the final concentration of 1nM of certain volume are added in 2mL EP pipes, control Group is biosensor blank, and one group of experimental group is that the matrix metalloproteinase activated is added into biosensor solution 2, after another group is added protein inhibitor Marimastat incubations 12 hours on this basis, three groups of samples are incubated at 37 DEG C It educates 30 minutes, spectral scan is carried out by sepectrophotofluorometer, is as a result illustrated in fig. 15 shown below.After albumen is added, fluorescence Intensity is significantly raised.After addition albumen adds protein inhibitor reaction a period of time, fluorescence intensity is declined, and illustrates to inhibit Agent can effectively inhibit the expression of mmp-2, Au-Se biosensors to can be very good to measure the situation of change of mmp-2 albumen.

Biosystem application

Cytotoxicity (MTT) is tested

Au-Se biosensor applications before living cells, are being selected breast cancer cell MCF-7 be research object, it is right The toxicity of the nano biological sensor is evaluated.There are a kind of enzyme in living cells mitochondria, it is called succinate dehydrogenase, it should MTT can be reduced to first a ceremonial jade-ladle, used in libation (Formazan, bluish violet crystalline material) under enzyme effect, it is not soluble in water, therefore can be deposited on thin In born of the same parents, however there is no this features for dead cell.The amount of the first a ceremonial jade-ladle, used in libation generated in experimentation is more, and living cells quantity is then more. This experiment detects cell activity by microplate reader, measures the absorbance at 490nm, is carried out to the absorbance before and after incubated cell Comparison, can calculate the survival rate of cell, to judge the biosensor to cytotoxicity.The experiment is received with 1nM's Meter Jin, Au-S biosensor, Au-Se biosensors difference incubated cell 0h, 3h, 6h, 9h, 12h and for 24 hours, it is as a result as follows Shown in Figure 16, it can be seen that with after biosensor incubated cell, the survival rate of cell illustrates to give birth to all shown as 85% or more Object sensor, without significantly toxicity, has preferable biocompatibility, this is to biosensor application in living cells to cell It is middle to realize that the detection of albumen is very important.

Sulfydryl substance removes experiment

Two kinds of biosensor storing solutions of the Au-S of synthesis and Au-Se are diluted with cell culture fluid, its end is made Concentration is 1nM.By HepG2 cell inoculations in four capsules, adherent growth for 24 hours after, tested.Experimental group is first with 500 μ M NEM incubated cell 20min, control group are not processed.The Au-S and Au- of final concentration of 1nM is added into culture dish again later After being incubated 4h at 37 DEG C, by cell dissociation, 150 μ L are added after centrifugation (500rpm, 2min) three times in two kinds of biosensors of Se PBS (no Ca²⁺And Mg²⁺), the signal of FITC is acquired with flow cytometer, is as a result illustrated in fig. 17 shown below.Figure 17 a represent Au-Se lifes Object sensor, Figure 17 b represent Au-S biosensors, it can be seen that before and after removing biological thiol with NEM, Au-Se biologies pass The intensity of cellular fluorescence that sensor is incubated is almost without any variation, and the cell that Au-S biosensors are incubated, and is given birth to removing There are one the false positive signals being remarkably reinforced to generate before object mercaptan, thus further judges that Au-Se biosensors can have Effect avoid distorted signals is detected caused by biological thiol.Au-Se biosensors present outstanding stability and strong Noiseproof feature, it is the accurate detection for realizing mmp-2 that this, which so that the biosensor can be very good,.

Au-Se biosensors in cell with the response of MMP-2

Normal cell and cancer cell is selected to carry out, in normal cell, the expression quantity of matrix metalloproteinase 2 is few, and Expression quantity rises in cancer cell.This experiment is divided into three groups, first by the Au-Se biosensors storing solution of synthesis with 1640, DMEM culture solutions are diluted, and make its final concentration of 1nM.By normal liver cell HL-7702, hepatocellular carcinoma H22, breast cancer Cell MCF-7 is seeded in the burnt ware of copolymerization and (200 μ L is added), in good condition after cell is adherent, pipettes final concentration of 1nM Au-Se biosensors be added in the burnt ware of copolymerization, continue to be incubated 4 hours, culture solution then taken out, with Tris buffer solutions The burnt ware of cleaning copolymerization three times, cleans biosensor residual, then carry out dyeing processing to nucleus, carries out laser co-focusing later Imaging, takes pictures and records fluorescence intensity level, be as a result illustrated in fig. 18 shown below.It can be seen that in normal liver cell from Figure 18 a, it is glimmering Optical signal is very weak, there is no fluorescence, and in liver cancer cells and breast cancer cell, it can be readily apparent that see green Fluorescence signal.Figure 18 b are the quantized value of fluorescence intensity, and it is intracellular that this illustrates that Au-Se biosensors can be very good to be applied to The detection of MMP-2, and normal cell and cancer cell can be distinguished.

Hepatocellular carcinoma H22, breast cancer cell MCF-7 are seeded in the burnt ware of copolymerization and (200 μ L are added), waits for cell state Well, adherent to be tested later, the Au-Se biosensors storing solution of synthesis is diluted with DMEM culture solutions, makes it Final concentration of 1nM.Experimental group first uses inhibitor incubated cell, control group to be not processed.The final concentration of of 200 μ L is pipetted later The Au-Se biosensors of 1nM are added in the burnt ware of copolymerization, continue to be incubated 4 hours, then carry out dyeing processing to nucleus, into Row laser confocal imaging takes pictures and records fluorescence intensity level, and as a result shown in following Figure 18 c, Figure 18 d are the quantization of fluorescence intensity It is worth in liver cancer cells and breast cancer cell, is added after inhibitor, the fluorescence intensity signals measured have apparent reduction, explanation Au-Se biosensors can be very good to detect the level of intracellular mmp-2.

Embodiment 3

The preparation method of the present embodiment refers to document YunWei Charles Cao, Rongchao Jin, Chad A.Mirkin.Nanoparticles with Raman Spectroscopic Fingerprints for DNA and RNA Sulfydryl therein is replaced with selenol group by Detection.Science 297 (5586), 1536-1540.It is prepared by the present embodiment Biosensor can be used for Raman sensing.

Embodiment 4

The preparation method of the present embodiment refers to document Yijing Liu, Jie He, Kuikun Yang, Chenglin Yi, Yi Liu,Liming Nie,Niveen M.Khashab,Xiaoyuan Chen,and Zhihong Nie.Folding Up of Gold Nanoparticle Strings into Plasmonic Vesicles for Enhanced Photoacoustic Imaging.Angew.Chem.2015,127,16035-16038, sulfydryl therein is replaced with into selenol Group.Biosensor manufactured in the present embodiment can be used for light sound sensor.

Embodiment 5

The preparation method of the present embodiment refers to document Shusheng Zhang, Jianping Xia, and Xuemei Li.Electrochemical Biosensor for Detection of Adenosine Based on Structure- Switching Aptamer and Amplification with Reporter Probe DNA Modified Au Nanoparticles.Anal.Chem.2008,80,8382-8388, sulfydryl therein is replaced with into selenol group.The present embodiment The biosensor of preparation can be used for electrochemical sensing.

The foregoing is merely the preferred embodiments of the application, are not intended to limit this application, for the skill of this field For art personnel, the application can have various modifications and variations.Within the spirit and principles of this application, any made by repair Change, equivalent replacement, improvement etc., should be included within the protection domain of the application.

SEQUENCE LISTING

<110>Shandong Normal University

<120>A kind of biosensor and preparation method based on golden selenium key

<130> 2018

<160> 1

<170> PatentIn version 3.5

<210> 1

<211> 9

<212> PRT

<213>Artificial sequence

<400> 1

Asp Gly Pro Leu Gly Val Arg Gly Cys

1 5

Claims

1. a kind of application of gold selenium key in biosensor, characterized in that sulfydryl and gold nano grain shape in biosensor At golden sulfide linkage replace with the golden selenium key that selenol group and gold nano grain formed.

2. a kind of biosensor, characterized in that include biomolecule and gold nano grain with recognition group, it is described to carry The biomolecule of recognition group contains selenol group, and the selenol group forms golden selenium key with gold nano grain, makes with identification The biomolecule and gold nano grain of group combine, each gold nano grain and at least one biomolecule with recognition group In conjunction with.

3. the biosensor described in a kind of claim 2 is in fluorescence sense, Raman sensing, light sound sensor and electrochemical sensing neck Application in domain.

4. a kind of biosensor based on golden selenium key, characterized in that described glimmering including fluorescein, peptide chain and gold nano grain Light element modifies the N-terminal in peptide chain, and the C-terminal amino acid of the peptide chain contains exposed selenol group, and the gold nano grain passes through Selenol group forms golden selenium key and peptide chain combination, each gold nano grain and at least one peptide chain combination.

5. the biosensor as claimed in claim 4 based on golden selenium key, characterized in that the amino acid sequence of peptide chain is Asp- Gly-Pro-Leu-Gly-Val-Arg-Gly-Cys, the Cys are seleno cysteine；Preferably, Cys is the C of peptide chain End.

6. the biosensor as claimed in claim 4 based on golden selenium key, characterized in that the size of the gold nano grain is 13±2nm；

Or, each gold nano grain and 10~300 peptide chain combinations.

7. a kind of preparation method of the biosensor based on golden selenium key described in claim 4, characterized in that modify N-terminal There is the peptide chain of fluorescein to be added into the dispersion liquid of gold nano grain, is protected from light after the reaction of stirring 36~72 hours can be obtained and is based on The biosensor of golden selenium key；Wherein, peptide chain C-terminal amino acid contains exposed selenol group.

8. preparation method as claimed in claim 7, characterized in that add surfactant into the dispersion liquid of gold nano grain Solution obtain mixed liquor, add the solution that N-terminal is modified with the peptide chain of fluorescein, be protected from light after the reaction of stirring 36~72 hours i.e. It can get the biosensor based on golden selenium key；

Preferably, the surfactant is lauryl sodium sulfate.

9. preparation method as claimed in claim 7, characterized in that a concentration of the 3 of the dispersion liquid of the gold nano grain ± 0.1nM；

Or, two kinds of solution after reaction are discarded supernatant liquid by centrifugal treating, precipitation is re-dissolved in secondary ultra-pure water, after Continuous to carry out centrifugation dissolving operation, centrifugation dissolving operating process is handled three times.

10. a kind of any biosensor based on golden selenium key of claim 4~6 is in detecting matrix metalloproteinase Application；

Preferably, each gold nano grain and 47 ± 5 peptide chain combinations.