Method for green synthesis of fluorescent chiral carbon dots

A green synthesis, chiral carbon technology, applied in the fields of nanomaterials science and biomedical engineering, can solve the problems of complex preparation scheme, difficult separation and purification, etc., and achieve the effects of controllable particle diameter, simple synthesis method and good reproducibility

Inactive Publication Date: 2014-04-02
SHANGHAI JIAO TONG UNIV
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Problems solved by technology

[0007] Aiming at defects such as the quantum yield points of fluorescent carbon dots currently synthesized, the preparation scheme is too complicated, and the separation and purification are difficult, the present invention proposes a new method for synthesizing chiral fluorescent carbon nanodots in one step, which is green and pollution-free. In this method, select 20 kinds of common amino acids, including different optically active amino acids, are used as activation and functional modification molecules. Using microwave synthesis, chiral fluorescent carbon dots with high fluorescence quantum yield can be obtained in one step.

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  • Method for green synthesis of fluorescent chiral carbon dots
  • Method for green synthesis of fluorescent chiral carbon dots
  • Method for green synthesis of fluorescent chiral carbon dots

Examples

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Effect test

Embodiment 1

[0029] Example 1, using citric acid as a precursor and L-tryptophan (L-Trp) as an auxiliary reagent to prepare fluorescent carbon dots.

[0030] Step 1: At room temperature, weigh 1g of citric acid, 10mg of L-tryptophan, and 5mL of H 2 O was added to a 25mL glass reaction bottle, and ultrasonic treatment was performed at a working frequency of 40kHz and an ultrasonic power of 200W for 1min to obtain a transparent aqueous solution.

[0031]Step 2: Put the mixed solution obtained in Step 1 into a microwave oven for 4 minutes at a power of 800W, and obtain a brownish-yellow liquid after reaction.

[0032] Step 3: Dialyze the product obtained in Step 2 with a dialysis bag with a molecular weight cut-off of 1000 for 36 hours. During the dialysis process, the ultrapure water should be replaced continuously to remove unreacted citric acid and tryptophan to obtain the fluorescence of the surface amino acid The carbon quantum dots have a fluorescence quantum yield of 19.27%.

Embodiment 2

[0033] Example 2, using glucose as a precursor and d-tryptophan (D-Trp) as a biosynthetic template to prepare fluorescent carbon dots.

[0034] Step 1: At room temperature, weigh 1 g of glucose, 5 mg of D-tryptophan, and 5 mL of H 2 O was added to a 25mL glass reaction bottle, and the working frequency was 40kHz, and the ultrasonic power was 200W, and the ultrasonic treatment was performed for 1min to obtain a uniform aqueous solution.

[0035] Step 2: Put the mixed solution obtained in Step 1 into a microwave oven for 4 minutes at a power of 800W, and obtain a brownish-yellow liquid after reaction.

[0036] Step 3: Dialyze the product obtained in Step 2 with a dialysis bag with a molecular weight cut-off of 1000 for 36 hours. During the dialysis process, the ultrapure water should be replaced continuously to remove unreacted glucose and tryptophan to obtain surface tryptophan-modified fluorescence Carbon dots have a fluorescence quantum yield of 9.57%.

Embodiment 3

[0037] Example 3, using glucose as a precursor and L-cysteine ​​and D-cysteine ​​as auxiliary synthesis reagents to prepare chiral fluorescent carbon dots.

[0038] Step 1: At room temperature, weigh 1g of glucose, 5mg of L-cysteine ​​and R-cysteine, and put them into 5mL H 2 In a 25mL glass reaction vial of O, the ultrasonic treatment was performed for 1min at a working frequency of 40kHz and an ultrasonic power of 200W to obtain a uniform aqueous solution.

[0039] Step 2: The mixed solutions obtained in Step 1 were respectively placed in a microwave oven for 4 min at a power of 800 W, and a brownish-yellow liquid was obtained after the reaction.

[0040] Step 3: Put the products obtained in step 2 into dialysis bags with a molecular weight cut-off of 1000 for dialysis for 36 hours respectively. During the dialysis process, the ultrapure water should be replaced continuously to remove unreacted glucose and cysteine, and obtain different molecular weights. The fluorescent ca...

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Abstract

The invention provides a method for green synthesis of fluorescent chiral carbon dots. The method comprises the steps of 1, ultrasonically dispersing a carbon precursor and amino acid in deionized water to prepare a transparent aqueous solution or latex, wherein the mass ratio of the carbon precursor to the amino acid is 200:1 to 5:1; 2, putting the mixed solution obtained in the step 1 into a microwave heating device for a microwave heating reaction so as to obtain yellow or brown-yellow liquid; 3, dialyzing the carbon quantum dot solution obtained through the reaction in the step 2 by a dialysis bag of which the molecular weight cut-off is 1,000-50,000 to remove unreacted carbon precursor and amino acid, thereby obtaining fluorescent carbon dots, of which the particle size distribution is narrow, without further purification. The method disclosed by the invention adopts a microwave synthetic method to obtain the chiral carbon dots with the relatively high fluorescent quantum yield through one step, the synthetic method is simple, the required equipment is simple, the repeatability is good, and the method is suitable for preparation of chiral carbon dots on a large scale.

Description

technical field [0001] The invention relates to the fields of nanomaterial science and biomedical engineering, in particular to a green method for synthesizing fluorescent chiral carbon dots, that is, a preparation method for assisting the synthesis of fluorescent carbon dots by using amino acids and their derivatives. Background technique [0002] Carbon nanomaterials, from carbon nanotubes to graphene, have always been a hot research topic because of their unique physical, chemical and optical properties. Carbon dots, as a new type of nano-carbon material, have gradually attracted your attention. Carbon dots, in a broad sense, are defined as: the diameter is generally 2 to 10nm, and after surface passivation, different fluorescence will be emitted, and the emission wavelength can be "tuned", which can realize one-dimensional excitation and multiple emission, and can absorb from visible light to near Infrared light has a large emission wavelength span, a wide Stokes shift,...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B31/02C09K11/65B82Y20/00B82Y40/00C01B32/15
Inventor 沈广霞王青刘慧旸崔大祥
Owner SHANGHAI JIAO TONG UNIV
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