CN109652065B - Preparation method of gold-doped fluorescent carbon quantum dots - Google Patents
Preparation method of gold-doped fluorescent carbon quantum dots Download PDFInfo
- Publication number
- CN109652065B CN109652065B CN201811452618.6A CN201811452618A CN109652065B CN 109652065 B CN109652065 B CN 109652065B CN 201811452618 A CN201811452618 A CN 201811452618A CN 109652065 B CN109652065 B CN 109652065B
- Authority
- CN
- China
- Prior art keywords
- gold
- aqueous solution
- carbon quantum
- quantum dots
- fluorescent carbon
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
- C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
- C09K11/58—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing copper, silver or gold
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y20/00—Nanooptics, e.g. quantum optics or photonic crystals
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y40/00—Manufacture or treatment of nanostructures
Abstract
The invention provides a preparation method of gold-doped fluorescent carbon quantum dots, which comprises the following steps: preparing a modified chitosan compound aqueous solution carrying gold nanoclusters; and uniformly mixing the modified chitosan compound aqueous solution carrying the gold nanoclusters with a citric acid aqueous solution, and carrying out hydrothermal reaction to obtain the gold-doped fluorescent carbon quantum dots. The method can provide the gold-doped fluorescent carbon quantum dots with double fluorescence emission wavelengths, which have low toxicity, good biocompatibility, good water solubility, high fluorescence yield and good storage stability.
Description
Technical Field
The invention belongs to the field of medical biochemical detection, and particularly relates to a gold-doped fluorescent carbon quantum dot with double fluorescence emission wavelengths and a preparation method thereof.
Background
In recent years, the quantum dot materials are most widely used, and researchers pay attention to the materials, but in recent years, researches show that quantum dots contain heavy metals such as chromium and selenium and have high toxicity, so that many scientists are trying to find new substitutes for the materials. Carbon Quantum Dots (CQD) are a new developed carbon nano-material, which is sp2The fluorescent nano-particles which are composed of hybridized carbon or amorphous carbon, can stably emit light, have the size less than 10nm and have a quasi-spherical structure are expected to replace semiconductor quantum dots to be used as medical fluorescent materials. In recent years, a plurality of carbon sources for preparing carbon quantum dots, such as graphite, glucose, citric acid and sepsis-resistant agent, have been developedAcids, gelatin, sucrose, polyparaffin derivatives, polyfuranose, polyglucose, and the like.
The single-signal fluorescent material is difficult to meet the development requirements of various disciplines, for example, the single fluorescent material can well complete the detection of molecular ions, the labeling of biomacromolecules and the like, but can not effectively separate and enrich the molecular ions to an effective amount so as to meet the requirements of the existing microanalyzer. The dual-signal (even multi-signal) fluorescent nano material can be excited by exciting light with different wavelengths, and further can be subjected to fluorescence imaging under different environments, so that the dual-signal (even multi-signal) fluorescent nano material has a good application prospect and is highly concerned by researchers in the fields of materials science, analytical chemistry, biology, medicine and pharmacology and the like.
Fluorescent nanomaterials typically include: semiconductor quantum dots, rare earth doped up-conversion nanomaterials, noble metal nanoparticles (such as gold nanoparticles), and carbon quantum dots. However, the preparation conditions of the semiconductor quantum dots are harsh, and the precursor is heavy metal ion salts such as Cd, Pb, Hg and the like, which cause great harm to human bodies and the environment, and the application of the semiconductor quantum dots is limited to a certain extent by the factors. The raw materials for making the upconverting material are relatively expensive. Therefore, gold nanoparticles and carbon quantum dots with low toxicity and good biocompatibility attract more researchers. Huanghong et al (Zhejiang university, Master thesis, 2014) have synthesized various novel fluorescent nanomaterials by using different carbon sources, studied the fluorescent characteristics and the target recognition performance thereof in detail, and deeply discussed the relevant target recognition mechanism: (1) synthesis of captopril-gold nanoparticles and Hg2+The targeted identification research uses captopril as a stabilizer and tetrakis (hydroxymethyl) phosphonium chloride as a reducing agent to synthesize fluorescent gold nanoparticles by a simple, mild, rapid (5 min) and green method, and Hg is utilized2+Can specifically quench the fluorescence of the gold nanoparticles, and the fluorescent gold nanoparticles can be used for Hg in an environmental water sample2+Rapidly detecting the content; (2) fluorescent gold nanoparticles with adjustable wavelength synthesized by polypeptide template method and different sequence structures adopted in performance researchThe polypeptide is used as a template, sodium borohydride is used as a reducing agent, fluorescent gold nanoparticles with different emission wavelengths are synthesized, and Hg can be realized by taking the gold nanoparticles as probes2+High sensitivity and high selectivity detection; (3) the nitrogen-doped fluorescent carbon quantum dots are synthesized by using strawberries as carbon sources and a hydrothermal method, have good water solubility and high stability, and can be used as a fluorescent probe for measuring Hg2+. (4) The method is characterized in that grapes are used as raw materials, a one-step hydrothermal method is adopted to synthesize the fluorescent carbon quantum dots with high quantum yield, and the carbon quantum dots have the characteristics of good water solubility, high stability, small particle size, uniform size, low cytotoxicity and the like and have good cell imaging capability.
When the size of the gold nanoparticles is gradually reduced to be comparable to the wavelength of the fischer-tropsch, the electronic structure is similar to that of a semiconductor, and the energy level is discontinuous. These ultra-small gold nanoparticles have fluorescent properties, also known as gold nanoclusters (AuNC). Gold nanoclusters have many advantages over traditional fluorescent probes. The quantum dot has the advantages of higher quantum yield, longer fluorescence life, strong photobleaching resistance, size dependence adjustability of emission spectrum wavelength, large Stokes shift and low biological toxicity. Therefore, the gold nanocluster as a novel fluorescent nano material is expected to be widely applied to the fields of biomarkers and fluorescence imaging. Suxiaqing et al (2016, university of southeast university Master thesis) explores a preparation method of the fluorescent gold nanocluster under different conditions by a chemical reduction method with chloroauric acid as a reaction precursor and GSH as a reducing agent, and further inspects the influence of thiol on the fluorescence intensity of the gold nanocluster.
Most of reported carbon quantum dots at present have low fluorescence quantum yield, so that the practical application of the carbon quantum dots in various fields is limited, and the surfaces of some carbon quantum dots lack effective recognition groups, so that the specific binding capacity of the carbon quantum dots to a target object is limited, and the selectivity is poor; the biochemical sensor constructed based on the carbon quantum dots mostly uses the change of single fluorescence emission intensity as a signal output unit, and has the problem that the fluorescence intensity is easily interfered by factors such as excitation light source intensity, probe concentration and the like, so that the detection accuracy needs to be improved. Higher officer jing arene et al (university of Hunan Master thesis 2017) used different raw materials,a series of carbon quantum dots with unique optical properties are prepared by a simple hydrothermal synthesis method. The method mainly comprises the following steps: (1) compared with fluorescent dyes, most of reported carbon quantum dots have the defect of low quantum yield, and the practical application of the carbon quantum dots in the field of biochemical sensing is greatly limited; (2) preparation of nitrogen and phosphorus co-doped high-fluorescence carbon quantum dot based fluorescent probe and Fe in biological sample3+The detection research of (1) selects adenosine triphosphate as a carbon source, a nitrogen source and a phosphorus source, synthesizes the nitrogen and phosphorus co-doped carbon quantum dot with high quantum yield in one step by a hydrothermal method in order to realize simple and rapid introduction of functional groups on the surface of the carbon quantum dot and improve the quantum yield by combining heteroatom doping, the carbon quantum dot has good fluorescence stability, low toxicity and water solubility, the quantum yield can reach 43.2%, analysis on the functional groups and element valence states shows that the surface of the carbon quantum dot contains a large number of functional groups such as carboxyl groups, phosphate groups and the like, and the nitrogen and phosphorus co-doped carbon quantum dot fluorescent probe can be used as Fe3+A new method of detection; (3) the preparation of the ratio-type fluorescent probe based on the label-free carbon quantum dots and the application research of the ratio-type fluorescent probe to intracellular pH sensing are carried out, and in order to further overcome the defects of dye leakage, complex cross-linking and purification steps and the like existing in the construction of the ratio-type fluorescent probe by combining the carbon quantum dots with fluorescent dye or other fluorescent nano materials, the label-free and double-emission fluorescent carbon quantum dots are prepared in one step by taking citric acid and basic fuchsin as reactants through a simple hydrothermal synthesis method. The carbon quantum dot has two fluorescence emission peaks at 475nm and 545nm respectively under the irradiation of 380nm exciting light, and the fluorescence emission intensity shows excellent light stability.
Disclosure of Invention
The invention aims to solve the technical problems and provide a gold-doped fluorescent carbon quantum dot with double fluorescence emission wavelengths, which has low toxicity, good biocompatibility, good water solubility and high fluorescence yield.
The invention also aims to provide a preparation method of the gold-doped fluorescent carbon quantum dot.
Therefore, the invention provides the following technical scheme.
A preparation method of gold-doped fluorescent carbon quantum dots comprises the following steps:
step 1, preparing a modified chitosan compound aqueous solution carrying gold nanoclusters: mixing 5-20 mL of modified chitosan aqueous solution with the mass concentration of 1% with 1-3 mL of chloroauric acid aqueous solution with the concentration of 4mol/L, then adding 3-5 mL of citric acid aqueous solution with the concentration of 4mol/L, uniformly mixing, and standing for 15-60 minutes; then adding 0.400g of a compound containing sulfur and nitrogen elements, stirring uniformly, adding 9-14 mL of a 4mol/L citric acid aqueous solution into a mixed system, uniformly mixing and standing to obtain the gold nanocluster-loaded modified chitosan compound aqueous solution, wherein the compound containing sulfur and nitrogen elements is any one of mercaptoethylamine or thioglycolic acid or ethylenediamine;
and 2, uniformly mixing 0.625-5 g of the modified chitosan compound aqueous solution carrying the gold nanocluster with 30mL of an aqueous solution containing 1-5 g of citric acid, and carrying out hydrothermal reaction at the temperature of 150-200 ℃ to obtain the gold-doped fluorescent carbon quantum dot.
As a preferred embodiment, the method further comprises purifying the gold-doped fluorescent carbon quantum dots after preparing the gold-doped fluorescent carbon quantum dots.
As a preferred embodiment, the purification treatment comprises: and centrifuging the gold-doped fluorescent carbon quantum dots and then dialyzing. The speed of centrifugation is preferably 5000 r/min to 12000 r/min, more preferably 6000 r/min to 10000 r/min.
In a preferred embodiment, the temperature at which the hydrothermal reaction is carried out in step 2 is preferably 160 to 190 ℃. More preferably 180 deg.c.
As a preferred embodiment, the hydrothermal reaction is carried out in step 2 for at least 300 minutes.
As a preferred embodiment, the modified chitosan is grafted and copolymerized with chitosan of a polymerized monomer N-vinyl pyrrolidone and a functional monomer acrylic acid.
Compared with the prior art, the gold-doped fluorescent carbon quantum dot has low toxicity, good biocompatibility, good water solubility, high fluorescence yield and good storage stability.
Drawings
FIG. 1 is an ultraviolet spectrum of gold-doped fluorescent carbon quantum dots prepared by using different modified chitosan complex aqueous solutions carrying gold nanoclusters when the total gold carrying amount is 1%.
FIG. 2 is a fluorescence spectrum of gold-doped fluorescent carbon quantum dots prepared by using different modified chitosan complex aqueous solutions carrying gold nanoclusters when the total gold carrying amount is 1%.
FIG. 3 is a fluorescence spectrum of gold-doped fluorescent carbon quantum dots prepared by using different modified chitosan complex aqueous solutions carrying gold nanoclusters when the total gold carrying amount is 2%.
FIG. 4 is a fluorescence spectrum of a gold-doped fluorescent carbon quantum dot prepared with an amount of 0.625g of an aqueous solution of a modified chitosan complex carrying gold nanoclusters when the total gold carrying amount is 2%, and having dual excitation wavelengths.
Fig. 5 is a TEM (transmission electron microscope) image of gold-doped fluorescent carbon quantum dots with dual excitation wavelengths.
FIG. 6 is a fluorescence spectrum of gold-doped fluorescent carbon quantum dots prepared by using different modified chitosan complex aqueous solutions carrying gold nanoclusters when the total gold carrying amount is 1%.
FIG. 7 is a fluorescence spectrum of gold-doped fluorescent carbon quantum dots prepared by using different modified chitosan complex aqueous solutions carrying gold nanoclusters when the total gold carrying amount is 2%.
FIG. 8 is a fluorescence spectrum of a gold-doped fluorescent carbon quantum dot prepared with an amount of 0.625g of an aqueous solution of a modified chitosan complex carrying gold nanoclusters when the total gold carrying amount is 3%, and having dual excitation wavelengths.
Detailed Description
The technical solution of the present invention will be further described with reference to the following specific examples, but the present invention is not limited to the following examples.
Unless otherwise specified, all reagents used in the present invention are available commercially. For the sake of brevity, some of the technical operations are not described in detail, but it is understood that these operations are within the purview of one skilled in the art and may be implemented in accordance with the teachings set forth herein.
The modified chitosan used in the invention is chitosan grafted and copolymerized with a polymerization monomer N-vinyl pyrrolidone and a functional monomer acrylic acid.
The specific steps for preparing the modified chitosan aqueous solution are as follows:
modified chitosan (CTS-g-P (NVP-co-AA)) is prepared by taking 1% (wt) shell and saccharic acid aqueous solution (CTS for short) as raw materials (88 parts), taking dilute nitric acid (0.5% wt) aqueous solution (20 parts) containing ceric sulfate (0.1 part) as an initiator, and carrying out graft copolymerization with a polymerization monomer N-vinyl pyrrolidone (10 parts) and a functional monomer (such as acrylic acid) (10 parts) under the condition of nitrogen protection at 45 ℃.
The test method is as follows:
(1) testing and characterization of gold-doped fluorescent carbon quantum dots
Observing the shapes and the particle sizes of the carbon quantum dots and the magnetic carbon quantum dots by adopting a Transmission Electron Microscope (TEM);
using carbon quantum (modified chitosan aqueous solution (3 mL)) synthesized by a system of 'modified chitosan + citric acid + mercaptoethylamine', adding 30mL of aqueous solution containing 3g of citric acid into the carbon quantum, uniformly mixing, performing hydrothermal reaction in a muffle furnace at 180 ℃ for 300 minutes to obtain a blank control, and measuring an ultraviolet spectrum;
the fluorescence properties of the samples were investigated using a fluorescence spectrophotometer (excitation wavelength: 356nm or 425nm, respectively).
(2) Determination of fluorescence yield of gold-doped fluorescent carbon quantum dots
A small amount of a standard quinine sulfate (QY ═ 0.577) is dissolved in a 0.05N sulfuric acid solution, and the integrated area of the emission peak and the ultraviolet absorbance (which need to be maintained at 0.05) of the analyte and quinine sulfate at the same wavelength (the maximum excitation wavelength of the standard) are measured as a reference, and the quantum yield is calculated as follows:
YQs＝YQr(Fs/Fr)(Ar/As)(ηs/ηr)2
QY is the quantum yield, F is the fluorescence emission peak area, a is the absorbance at the excitation wavelength, and η is the refractive index of the solvent. Wherein s represents an analyte; r represents a reference substance.
Example 1:
when the total gold loading amount is 1%, the amount of the modified chitosan compound aqueous solution of the gold-loaded nano cluster is changed, and the gold-doped fluorescent carbon quantum dots are prepared in a citric acid and mercaptoethylamine system
(1) Mixing 10mL of 1% (wt) modified chitosan aqueous solution and 1mL of 4mol/L chloroauric acid aqueous solution, adding 3mL of 4mol/L citric acid aqueous solution, uniformly mixing, and standing for 30 minutes (15-60 minutes); and adding 0.400g of mercaptoethylamine, stirring uniformly, adding 12mL of 4mol/L citric acid aqueous solution into the mixed system, uniformly mixing, and standing for at least 3h to obtain the gold nanocluster-loaded modified chitosan compound aqueous solution.
(2) Taking 1.25g, 2.5g and 5g of modified chitosan compound aqueous solution of gold-loaded nanocluster with the gold loading amount of 1%, adding 30mL of aqueous solution containing 2.5g of citric acid, uniformly mixing, and performing hydrothermal reaction in a muffle furnace at 180 ℃ for at least 300 minutes to prepare a crude product.
(3) And (4) carrying out proper purification treatment (centrifuging at the speed of 5000 r/min to 12000 r/min, more preferably 6000 r/min to 10000 r/min, most preferably 8000 r/min for 30 minutes, then filling the mixture into a 2000Da dialysis bag for pure water dialysis for 72 hours, and freezing and drying the mixture for later use, or directly refrigerating and storing the mixture in a refrigerator) to obtain the gold-doped fluorescent carbon quantum dots.
The TEM image shows that the gold-doped fluorescent carbon quantum dots obtained in the example are approximately spherical and have an average diameter of about 7.5 nm.
The obtained gold-doped fluorescent carbon quantum dot sample was diluted 15000 times and tested. The results show that the appearance color of the product is different according to the added amount of the modified chitosan complex aqueous solution carrying the gold nanoclusters, wherein 1.25g of the modified chitosan complex aqueous solution is brown, 2.5g of the modified chitosan complex aqueous solution is yellow, and 5g of the modified chitosan complex aqueous solution is brown. The UV spectrum is shown in FIG. 1, the fluorescence spectrum is shown in FIG. 2, and the value "14000" in FIG. 2 indicates that the sample of the same concentration is diluted 14000 times before the test.
According to the test result, when the gold-doped fluorescent carbon quantum dot aqueous solution prepared by a citric acid and mercaptoethylamine system is used, the peak value of an emission spectrum under the action of 365nm exciting light is about 450 nm; the peak of the emission spectrum when under the action of 425nm excitation light is about 500 nm; it follows that the gold-doped fluorescent carbon quantum dots "respond" to excitation light of dual wavelengths.
Example 2:
when the total gold loading amount is 1%, the amount of the modified chitosan compound aqueous solution loading the gold nanoclusters is changed, and the gold-doped fluorescent carbon quantum dots are prepared in a citric acid and thioglycollic acid system
(1) Mixing 20mL of 1% (wt) modified chitosan aqueous solution and 1mL of 4mol/L chloroauric acid aqueous solution, adding 3mL of 4mol/L citric acid aqueous solution, uniformly mixing, and standing for 30 minutes (15-60 minutes); then 0.400g of thioglycollic acid is added, after the mixture is stirred uniformly, 14mL of 4mol/L citric acid aqueous solution is added into the mixed system, the mixture is mixed uniformly and stands for at least 3 hours, and the gold nanocluster-loaded modified chitosan compound aqueous solution is obtained.
(2) 0.625g, 1.25g, 2.5g and 5g of modified chitosan complex aqueous solution of gold-loaded nanocluster with the gold loading amount of 1 percent are respectively taken, 30mL of aqueous solution containing 1.5g of citric acid is added into the aqueous solution, and after the aqueous solution and the aqueous solution are uniformly mixed, the aqueous solution and the aqueous solution are subjected to hydrothermal reaction in a muffle furnace at 160 ℃ for at least 300 minutes to prepare a crude product.
(3) And (4) carrying out proper purification treatment (centrifuging at the speed of 5000 r/min to 12000 r/min, more preferably 6000 r/min to 10000 r/min, most preferably 8000 r/min for 30 minutes, then filling the mixture into a 2000Da dialysis bag for pure water dialysis for 72 hours, and freezing and drying the mixture for later use, or directly refrigerating and storing the mixture in a refrigerator) to obtain the gold-doped fluorescent carbon quantum dots.
And diluting the obtained gold-doped fluorescent carbon quantum dot sample by 10000 times, and testing. The results are shown in FIG. 6, which shows that the fluorescence intensity of the product obtained in this example is lower than that of the corresponding sample in FIG. 2 (curve A in FIG. 2).
The TEM image shows that the gold-doped fluorescent carbon quantum dots obtained in the example are approximately spherical and have an average diameter of about 7.5 nm.
According to the test result, the peak value of the emission spectrum of the gold-doped fluorescent carbon quantum dot aqueous solution prepared by the citric acid and thioglycollic acid system under the action of 365nm exciting light is about 450 nm; the peak of the emission spectrum when under the action of 425nm excitation light is about 500 nm; it follows that the gold-doped fluorescent carbon quantum dots "respond" to excitation light of dual wavelengths.
Example 3:
when the total gold-loading amount is 2%, the amount of the modified chitosan compound aqueous solution of the gold-loading nano cluster is changed, and the gold-doped fluorescent carbon quantum dots are prepared in a citric acid and mercaptoethylamine system
(1) Mixing 10mL of 1% (wt) modified chitosan aqueous solution and 2mL of 4mol/L chloroauric acid aqueous solution, adding 3mL of 4mol/L citric acid aqueous solution, uniformly mixing, and standing for 30 minutes (15-60 minutes); and adding 0.400g of mercaptoethylamine, stirring uniformly, adding 12mL of 4mol/L citric acid aqueous solution into the mixed system, uniformly mixing, and standing for at least 3h to obtain the gold nanocluster-loaded modified chitosan compound aqueous solution.
(2) 0.625g, 1.25g, 2.5g and 5g of modified chitosan complex aqueous solution of gold-loaded nanocluster with the gold loading amount of 1 percent are respectively taken, 30mL of aqueous solution containing 2.5g of citric acid is added into the aqueous solution, and after the aqueous solution and the aqueous solution are uniformly mixed, the aqueous solution and the aqueous solution are subjected to hydrothermal reaction in a muffle furnace at 190 ℃ for at least 300 minutes to prepare a crude product.
(3) And (4) carrying out proper purification treatment (centrifuging at the speed of 5000 r/min to 12000 r/min, more preferably 6000 r/min to 10000 r/min, most preferably 8000 r/min for 30 minutes, then filling the mixture into a 2000Da dialysis bag for pure water dialysis for 72 hours, and freezing and drying the mixture for later use, or directly refrigerating and storing the mixture in a refrigerator) to obtain the gold-doped fluorescent carbon quantum dots.
The TEM image shows that the gold-doped fluorescent carbon quantum dots obtained in the example are approximately spherical and have an average diameter of about 7.5 nm.
The obtained gold-doped fluorescent carbon quantum dot sample was diluted 15000 times and tested. The results show that the product appearance was brown in color. The fluorescence spectrum is shown in FIG. 3.
According to the test result, when the gold-doped fluorescent carbon quantum dot aqueous solution prepared by a citric acid and mercaptoethylamine system is used, the peak value of an emission spectrum under the action of 365nm exciting light is about 450 nm; the peak of the emission spectrum when under the action of 425nm excitation light is about 500 nm; it follows that the gold-doped fluorescent carbon quantum dots "respond" to excitation light of dual wavelengths.
Example 4:
when the total gold loading amount is 2%, the amount of the modified chitosan compound aqueous solution loading the gold nanoclusters is changed, and the gold-doped fluorescent carbon quantum dots are prepared in a citric acid and ethylenediamine system
(1) Mixing 5mL of 1% (wt) modified chitosan aqueous solution and 2mL of 4mol/L chloroauric acid aqueous solution, adding 3mL of 4mol/L citric acid aqueous solution, uniformly mixing, and standing for 30 minutes (15-60 minutes); and then adding 0.400g of ethylenediamine, stirring uniformly, then adding 14mL of 4mol/L citric acid aqueous solution into the mixed system, uniformly mixing, and standing for at least 3h to obtain the gold nanocluster-loaded modified chitosan compound aqueous solution.
(2) 0.625g, 1.25g, 2.5g and 5g (an additional 10g of sample) of the gold-loaded nanocluster-loaded modified chitosan complex aqueous solution with the gold loading amount of 2% are taken, 30mL of an aqueous solution containing 1.0g of citric acid is added into the aqueous solution, and after the mixture is uniformly mixed, the mixture is subjected to hydrothermal reaction in a muffle furnace at 150 ℃ for at least 300 minutes to prepare a crude product (with generation of a large amount of black solid precipitate).
(3) And (4) carrying out proper purification treatment (centrifuging at the speed of 5000 r/min to 12000 r/min, more preferably 6000 r/min to 10000 r/min, most preferably 8000 r/min for 30 minutes, then filling the mixture into a 2000Da dialysis bag for pure water dialysis for 72 hours, and freezing and drying the mixture for later use, or directly refrigerating and storing the mixture in a refrigerator) to obtain the gold-doped fluorescent carbon quantum dots.
The TEM image shows that the gold-doped fluorescent carbon quantum dots obtained in the example are approximately spherical, and the average diameter of the base is about 7.5 nm.
And diluting the obtained gold-doped fluorescent carbon quantum dot sample by 1000 times, and testing.
From the test results (fig. 7), it can be seen that the peak value of the emission spectrum under the action of 365nm excitation light is about 450nm when the gold-doped fluorescent carbon quantum dot aqueous solution prepared by the system of citric acid and ethylenediamine is taken as an example (diluted by 10 times) of the sample with 0.625g of the modified chitosan complex aqueous solution; the peak of the emission spectrum when under the action of 425nm excitation light is about 500 nm; it follows that the gold-doped fluorescent carbon quantum dots "respond" to excitation light of dual wavelengths.
Example 5:
the total gold-loaded amount is 2%, the dosage of the modified chitosan compound aqueous solution loaded with the gold nanoclusters is 0.625g, and the gold-doped fluorescent carbon quantum dots are prepared in a citric acid and mercaptoethylamine system
(1) Mixing 10mL of 1% (wt) modified chitosan aqueous solution and 2mL of 4mol/L chloroauric acid aqueous solution, adding 3mL of 4mol/L citric acid aqueous solution, uniformly mixing, and standing for 30 minutes (15-60 minutes); and adding 0.400g of mercaptoethylamine, stirring uniformly, adding 12mL of 4mol/L citric acid aqueous solution into the mixed system, uniformly mixing, and standing for at least 3h to obtain the gold nanocluster-loaded modified chitosan compound aqueous solution.
(2) 0.625g of modified chitosan complex aqueous solution of gold-loaded nanoclusters with the gold loading amount of 2 percent is taken, 30mL of aqueous solution containing 2.5g of citric acid is added into the aqueous solution, and the mixture is uniformly mixed and then undergoes hydrothermal reaction in a muffle furnace at 180 ℃ for 300 minutes to prepare a crude product.
(3) And (4) carrying out proper purification treatment (centrifuging at the speed of 5000 r/min to 12000 r/min, more preferably 6000 r/min to 10000 r/min, most preferably 8000 r/min for 30 minutes, then filling the mixture into a 2000Da dialysis bag for pure water dialysis for 72 hours, and freezing and drying the mixture for later use, or directly refrigerating and storing the mixture in a refrigerator) to obtain the gold-doped fluorescent carbon quantum dots.
The TEM image (FIG. 5) shows that the gold-doped fluorescent carbon quantum dots obtained in the example are approximately spherical and have an average diameter of about 7.5 nm.
And diluting the obtained gold-doped fluorescent carbon quantum dot sample by 45000 times for testing. The experimental results of the corresponding tests are shown in fig. 4. As can be seen from FIG. 4, the peak value of the emission spectrum of the gold-doped fluorescent carbon quantum dot aqueous solution prepared by the system of "citric acid + mercaptoethylamine" under the action of 365nm excitation light is about 450 nm; the peak of the emission spectrum when acted on by excitation light at 425nm is about 510 nm; it follows that the gold-doped fluorescent carbon quantum dots "respond" to excitation light of dual wavelengths.
Example 6:
the total gold-loaded amount is 3 percent, the dosage of the modified chitosan compound aqueous solution loaded with the gold nanoclusters is 0.625g, and the gold-doped fluorescent carbon quantum dots are prepared in a citric acid and mercaptoethylamine system
(1) Mixing 10mL of 1% (wt) modified chitosan aqueous solution and 3mL of 4mol/L chloroauric acid aqueous solution, adding 5mL of 4mol/L citric acid aqueous solution, uniformly mixing, and standing for 30 minutes (15-60 minutes); and adding 0.400g of mercaptoethylamine, stirring uniformly, adding 9mL of 4mol/L citric acid aqueous solution into the mixed system, uniformly mixing, and standing for at least 3h to obtain the gold nanocluster-loaded modified chitosan compound aqueous solution.
(2) 0.625g of modified chitosan complex aqueous solution of gold-loaded nanoclusters with the gold loading amount of 3 percent is taken, 30mL of aqueous solution containing 5.0g of citric acid is added into the aqueous solution, and the mixture is subjected to hydrothermal reaction in a muffle furnace at 200 ℃ for 300 minutes after being uniformly mixed to prepare a crude product.
(3) And (4) carrying out proper purification treatment (centrifuging at the speed of 5000 r/min to 12000 r/min, more preferably 6000 r/min to 10000 r/min, most preferably 8000 r/min for 30 minutes, then filling the mixture into a 2000Da dialysis bag for pure water dialysis for 72 hours, and freezing and drying the mixture for later use, or directly refrigerating and storing the mixture in a refrigerator) to obtain the gold-doped fluorescent carbon quantum dots.
The TEM image shows that the gold-doped fluorescent carbon quantum dots obtained in the example are approximately spherical and have an average diameter of about 7.5 nm.
And diluting the obtained gold-doped fluorescent carbon quantum dot sample by 50000 times, and testing. The corresponding test results (fig. 8) are comparable to the corresponding samples in fig. 3 (curve a in fig. 3).
According to the test result, when the gold-doped fluorescent carbon quantum dot aqueous solution prepared by a citric acid and mercaptoethylamine system is used, the peak value of an emission spectrum under the action of 365nm exciting light is about 450 nm; the peak of the emission spectrum when under the action of 425nm excitation light is about 500 nm; it follows that the gold-doped fluorescent carbon quantum dots "respond" to excitation light of dual wavelengths.
Claims (7)
1. A preparation method of gold-doped fluorescent carbon quantum dots comprises the following steps:
step 1, preparing a modified chitosan compound aqueous solution carrying gold nanoclusters: mixing 5-20 mL of modified chitosan aqueous solution with the mass concentration of 1% with 1-3 mL of chloroauric acid aqueous solution with the concentration of 4mol/L, then adding 3-5 mL of citric acid aqueous solution with the concentration of 4mol/L, uniformly mixing, and standing for 15-60 minutes; then adding 0.400g of a sulfur or nitrogen-containing compound, stirring uniformly, adding 9-14 mL of a 4mol/L citric acid aqueous solution into a mixed system, uniformly mixing, and standing to obtain the gold nanocluster-loaded modified chitosan compound aqueous solution, wherein the sulfur or nitrogen-containing compound is any one of mercaptoethylamine or thioglycolic acid or ethylenediamine;
step 2, uniformly mixing 0.625-5 g of modified chitosan compound aqueous solution carrying gold nanoclusters with 30mL of aqueous solution containing 1-5 g of citric acid, and carrying out hydrothermal reaction at the temperature of 150-200 ℃ to obtain the gold-doped fluorescent carbon quantum dots;
the modified chitosan is chitosan grafted and copolymerized with a polymerization monomer N-vinyl pyrrolidone and a functional monomer acrylic acid.
2. The method according to claim 1, further comprising purifying the gold-doped fluorescent carbon quantum dots after the gold-doped fluorescent carbon quantum dots are prepared.
3. The method of claim 2, wherein the purification process comprises: and centrifuging the gold-doped fluorescent carbon quantum dots and then dialyzing.
4. The method of claim 3, wherein the speed of centrifugation is from 5000 r/min to 12000 r/min.
5. The method of claim 3, wherein the speed of centrifugation is from 6000 r/min to 10000 r/min.
6. The method of claim 1, wherein the hydrothermal reaction in step 2 is carried out at a temperature of 160 ℃ to 190 ℃.
7. The method of claim 1, wherein the hydrothermal reaction is carried out in step 2 for a period of at least 300 minutes.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811452618.6A CN109652065B (en) | 2018-11-30 | 2018-11-30 | Preparation method of gold-doped fluorescent carbon quantum dots |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811452618.6A CN109652065B (en) | 2018-11-30 | 2018-11-30 | Preparation method of gold-doped fluorescent carbon quantum dots |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109652065A CN109652065A (en) | 2019-04-19 |
| CN109652065B true CN109652065B (en) | 2021-08-20 |
Family
ID=66112117
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201811452618.6A Active CN109652065B (en) | 2018-11-30 | 2018-11-30 | Preparation method of gold-doped fluorescent carbon quantum dots |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109652065B (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110157421A (en) * | 2019-04-22 | 2019-08-23 | 山西大学 | A kind of gold nanoclusters/carbon dots composite fluorescent nano particle and preparation method thereof and the application in tetracycline detection |
| CN110387233B (en) * | 2019-08-08 | 2021-02-12 | 西南大学 | Simple mass-producible green fluorescent carbon dot and preparation method and application thereof |
| CN111175271B (en) * | 2020-03-03 | 2021-05-04 | 湖南格美特生物科技有限公司 | Lipase activity detection method based on fluorescent probe |
| CN112521534B (en) * | 2020-11-26 | 2021-10-15 | 大连理工大学 | Preparation method of cluster-induced high-fluorescence non-conjugated polymer |
| CN113218920B (en) * | 2021-02-04 | 2022-12-23 | 安徽师范大学 | Fluorescent carbon based on chrysanthemum preparation method of nano-microsphere and para-Hg 2+ Detection of Subtopril |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104356430A (en) * | 2014-11-17 | 2015-02-18 | 武汉理工大学 | Preparation method of carbon dot/chitosan in-situ composite material |
| CN104549407A (en) * | 2015-02-03 | 2015-04-29 | 哈尔滨工业大学 | Preparation method of platinum based/nitrogen doped carbon quantum dot-carbon nanotube catalyst |
| CN105067577A (en) * | 2015-07-14 | 2015-11-18 | 天津大学 | Dual emission rate type fluorescent probe for visually detecting carbon dots-Au nanoclusters of mercury ions and preparation method |
| CN105778906A (en) * | 2016-04-15 | 2016-07-20 | 哈尔滨工业大学 | Method for synthesizing metallic element in-situ doped fluorescence carbon dots deriving from chitosan biomass |
| CN106047342A (en) * | 2016-06-23 | 2016-10-26 | 南京理工大学 | Carbon quantum dot/aurum cluster ratiometric fluorescent probe for detection of cadmium ion and ascorbic acid |
| CN106672941A (en) * | 2016-12-27 | 2017-05-17 | 大连理工大学 | Preparation and separation method of magnetic nanometer fluorescent carbon dot |
| CN107601456A (en) * | 2017-09-21 | 2018-01-19 | 安康德美（中山）纳米科技有限公司 | A kind of high-performance fluorescent carbon quantum dot and preparation method thereof |
-
2018
- 2018-11-30 CN CN201811452618.6A patent/CN109652065B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104356430A (en) * | 2014-11-17 | 2015-02-18 | 武汉理工大学 | Preparation method of carbon dot/chitosan in-situ composite material |
| CN104549407A (en) * | 2015-02-03 | 2015-04-29 | 哈尔滨工业大学 | Preparation method of platinum based/nitrogen doped carbon quantum dot-carbon nanotube catalyst |
| CN105067577A (en) * | 2015-07-14 | 2015-11-18 | 天津大学 | Dual emission rate type fluorescent probe for visually detecting carbon dots-Au nanoclusters of mercury ions and preparation method |
| CN105778906A (en) * | 2016-04-15 | 2016-07-20 | 哈尔滨工业大学 | Method for synthesizing metallic element in-situ doped fluorescence carbon dots deriving from chitosan biomass |
| CN106047342A (en) * | 2016-06-23 | 2016-10-26 | 南京理工大学 | Carbon quantum dot/aurum cluster ratiometric fluorescent probe for detection of cadmium ion and ascorbic acid |
| CN106672941A (en) * | 2016-12-27 | 2017-05-17 | 大连理工大学 | Preparation and separation method of magnetic nanometer fluorescent carbon dot |
| CN107601456A (en) * | 2017-09-21 | 2018-01-19 | 安康德美（中山）纳米科技有限公司 | A kind of high-performance fluorescent carbon quantum dot and preparation method thereof |
Non-Patent Citations (3)
| Title |
|---|
| A highly selective and sensitive "on-off-on"fluorescent probe for detecting Hg(II) based on Au/N-doped carbon quantum dots;Alan Meng等;《Sensors and Actuators B:Chemical》;20170807;第255卷;第657-665页 * |
| Full-Range pH Stable Au-Clusters in Nanogel for Confinement-Enhanced Emission and Improved Sulfide Sensing in Living Cells;Xilin Bai等;《Analytical Chemistry》;20180212;第90卷;第3270-3275页 * |
| Highly Luminescent Thiolated Gold Nanoclusters Impregnated in Nanogel;Nirmal Goswami等;《Chemistry of Materials》;20160520;第28卷;第4009-4016页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN109652065A (en) | 2019-04-19 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN109652065B (en) | Preparation method of gold-doped fluorescent carbon quantum dots | |
| Qu et al. | Ratiometric fluorescent nanosensor based on water soluble carbon nanodots with multiple sensing capacities | |
| Dong et al. | Study of fluorescence quenching and dialysis process of CdTe quantum dots, using ensemble techniques and fluorescence correlation spectroscopy | |
| US9664677B2 (en) | Polymer-nanostructure composition for selective molecular recognition | |
| Zhang et al. | Synthesis of positively charged CdTe quantum dots and detection for uric acid | |
| Loukanov et al. | Photosensitizer-conjugated ultrasmall carbon nanodots as multifunctional fluorescent probes for bioimaging | |
| Di et al. | Fluorescent sensing of colloidal CePO4: Tb nanorods for rapid, ultrasensitive and selective detection of vitamin C | |
| Wang et al. | Bi-functional fluorescent polymer dots: a one-step synthesis via controlled hydrothermal treatment and application as probes for the detection of temperature and Fe 3+ | |
| Huerta-Aguilar et al. | Simultaneous recognition of cysteine and cytosine using thiophene-based organic nanoparticles decorated with Au NPs and bio-imaging of cells | |
| Zheng et al. | An enzyme-free fluorescent sensing platform for the detection of uric acid in human urine | |
| CN109777412B (en) | Double-emission fluorescent carbon dot and preparation method and application thereof | |
| Hu et al. | A rapid and sensitive turn-on fluorescent probe for ascorbic acid detection based on carbon dots–MnO 2 nanocomposites | |
| He et al. | Mn-doped ZnS quantum dots/methyl violet nanohybrids for room temperature phosphorescence sensing of DNA | |
| CN108467732A (en) | A kind of fluorescence molybdenum disulfide quantum dot and its preparation method and application | |
| CN108517208A (en) | The preparation method and its Cu of rare earth ratio fluorescent probe2+Detection application | |
| Saha et al. | Role of quantum dot in designing FRET based sensors | |
| Mao et al. | Cytosine-rich ssDNA-templated fluorescent silver and copper/silver nanoclusters: optical properties and sensitive detection for mercury (II) | |
| Dong et al. | Polymerizing dopamine onto Q-graphene scaffolds towards the fluorescent nanocomposites with high aqueous stability and enhanced fluorescence for the fluorescence analysis and imaging of copper ions | |
| EP2849803A1 (en) | Monolayer protected nanoclusters and methods of making and using thereof | |
| Chen et al. | One-step rapid synthesis of fluorescent silicon nanodots for a hydrogen peroxide-related sensitive and versatile assay based on the inner filter effect | |
| Jin et al. | Two-photon excited quantum dots with compact surface coatings of polymer ligands used as an upconversion luminescent probe for dopamine detection in biological fluids | |
| Zhao et al. | A single-particle enumeration method for the detection of Fe 2+ based on a near-infrared core–shell upconversion nanoparticle and IR-808 dye composite nanoprobe | |
| Li et al. | Facile aqueous synthesis of functionalized CdTe nanoparticles and their application as fluorescence probes for determination of adenine and guanine | |
| Li et al. | Switch-on hydrogel biosensor based on self-assembly Mn-doped ZnS QDs and cellulose nanofibrils for glutathione detection | |
| Sasikumar et al. | Fluorescent carbon dots for highly sensitive bilirubin sensing with excellent selectivity |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |