CN108659814B - Quaternary water-soluble quantum dot and preparation method and application thereof - Google Patents

Abstract

The invention discloses a quaternary water-soluble quantum dot, which comprises an AgGaInS core and a coating agent coated on the surface of the AgGaInS core; the invention also discloses a preparation method and application of the quantum dot. The quantum dots obtained by the step-by-step hydrothermal method have high crystallinity, uniform size distribution, wide adjustable range of fluorescence peak between 450 nm and 750nm and fluorescence quantum yield of more than 25%; in addition, the oligopeptide containing bioactive macromolecules is selected as the surface coating agent, so that the nano-particle can be well applied to photoelectric devices and biomarkers.

Description

A kind of quaternary water-soluble quantum dot and its preparation method and application

technical field

The invention relates to the field of quantum dot materials, in particular to a quaternary water-soluble quantum dot and a preparation method and application thereof.

Background technique

Semiconductor nanocrystals (NCs), also known as quantum dots (QDs), are semiconductor materials that are restricted in all three dimensions of space; quantum dots have been studied so far, and various types of structures have appeared. and materials; in terms of structure, there are core-shell structures, alloy structures, heterostructures, etc.; in terms of material types, there are II-VI groups (such as CdS), III-V groups (such as InP), etc.; these kinds of quantum It has a long development process, so the synthesis process is very mature, but it contains A-type heavy metal elements, such as Cd, Hg, etc., so it has caused huge damage to the biological environment.

Since the successful synthesis of AgInS ₂ quantum dots in 2007, the research on I-III-V ternary quantum dots has been started; ternary quantum dots have high light absorption coefficient, good biocompatibility and However, most of the currently synthesized ternary I-III-V quantum dots are organically synthesized, and the quantum yield is generally low, which greatly limits their use in luminescent materials and luminescent materials. Applications in the field of biomarkers.

SUMMARY OF THE INVENTION

In view of this, the main purpose of the present invention is to provide a quaternary water-soluble quantum dot, which solves the problems of low quantum yield and poor biocompatibility of quantum dots in the prior art.

In order to achieve the above object, the technical solution of the present invention is realized as follows: a quaternary water-soluble quantum dot, which includes a core of AgGaInS and a coating agent coated on the surface of the core of AgGaInS.

Preferably, the coating consists of glutathione analog and sodium citrate.

Another technical scheme of the present invention is realized in this way: a preparation method of quaternary water-soluble quantum dots, the method is realized by the following steps:

Step 1, adding an aqueous solution containing a coating agent to the mixed aqueous solution containing silver salt, indium salt and gallium salt and stirring uniformly to obtain a precursor solution;

Step 2, adjusting the pH value of the precursor solution obtained in the step 1 to 8-10.5 to obtain an alkaline precursor solution;

Step 3, adding an aqueous solution containing a sulfur source to the alkaline precursor solution obtained in the step 2 and stirring evenly to obtain a mixed aqueous solution containing the alkaline precursor and the sulfur source;

Step 4, performing step-by-step hydrothermal treatment on the mixed aqueous solution containing the alkaline precursor and the sulfur source obtained in the step 3 to obtain quaternary water-soluble quantum dots (AgGaInS quantum dots coated with a surface coating agent).

Preferably, in the step 1, the ratio of the molar amount of indium ions and gallium ions to the molar amount of silver ions in the mixed aqueous solution containing silver salt, indium salt and gallium salt is 1:(0.05～1) ; The ratio of the molar amount of indium ion, gallium ion, silver ion in the mixed aqueous solution containing silver salt, indium salt, gallium salt and the molar amount of the coating agent in the aqueous solution containing the coating agent is 1: ( 6 to 15).

Preferably, in the step 1, the amount concentration of silver ions in the mixed aqueous solution containing silver salt, indium salt and gallium salt is 0.01-0.15mol/L, and the amount concentration of indium ions is 0.01-0.15mol /L, the substance concentration of gallium ions is 0.01-0.15 mol/L; the substance concentration of the coating agent in the aqueous solution containing the coating agent is 0.01-0.6 mol/L.

Preferably, in the step 1, the silver salt is at least one of silver nitrate and silver acetate; the indium salt is at least one of indium nitrate, indium acetate and indium chloride; the gallium salt is At least one of gallium nitrate, gallium sulfate, and gallium chloride.

Preferably, in the step 3, the ratio of the sum of the molar amounts of indium ions, gallium ions and silver ions in the alkaline precursor to the molar amount of sulfur in the aqueous solution containing the sulfur source is 1: (1-20) The amount concentration of sulfur element in the sulfur source aqueous solution is 0.01-0.15 mol/L; the sulfur source is at least one of thioacetamide, thiourea and sodium sulfide.

Preferably, the specific method in the step 4 is: heating the mixed aqueous solution containing the alkaline precursor and the sulfur source to 60-80°C, at a constant temperature of 30-50min, and then heating it to 110-120°C at a constant temperature of 120-240min , cooling and centrifugal separation to obtain quaternary water-soluble quantum dots.

The quaternary water-soluble quantum dots of the invention are mostly used as fluorescent probes; the fluorescent probes are mainly used in the fields of optoelectronics, biology and medicine.

Compared with the prior art, the quantum dots obtained by adopting the step-by-step hydrothermal method have very high crystallinity, very uniform size distribution, a wide adjustable range of fluorescence peaks ranging from 450 to 750 nm, and the fluorescence quantum yield is as high as 25. % or more; in addition, the present invention can be well applied to optoelectronic devices and biological markers by selecting oligopeptides containing biologically active macromolecules as surface coating agents.

Description of drawings

Fig. 1 is the synthetic schematic diagram of quaternary water-soluble quantum dots provided in the embodiment of the present invention;

2 is a high-resolution transmission electron microscope image of quaternary water-soluble quantum dots provided in an embodiment of the present invention;

Fig. 3 is the fluorescence spectrogram of the quaternary water-soluble quantum dot provided in the embodiment of the present invention;

4 is a schematic diagram of the fluorescence quantum yield of the quaternary water-soluble quantum dots provided in the embodiment of the present invention;

FIG. 5 is a schematic diagram of the cytotoxicity detection results of the quaternary water-soluble quantum dots provided in the embodiment of the present invention.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention.

The symbols and formulae used in the present invention have the meanings known in the art. Specifically, AgGaInS represents an alloy composed of silver, indium, gallium and sulfur elements; Glu-Cys-Pro oligopeptide is glutamic acid-cysteine-proline tripeptide; coated on the surface of quantum dots Glu-Cys-Pro oligopeptides are surface-modified biocompatible ligands that complex with metal ions on the surface. It should be understood that although they are referred to herein as surface coating agents, they are not intended to limit their role as surface coating only in the method of the present invention.

The present invention provides an embodiment to provide a quaternary water-soluble quantum dot, which includes a core of AgGaInS and a coating agent coated on the surface; wherein, the surface coating agent is composed of glutathione analog and sodium citrate Compositionally, the glutathione analog is a Glu-Cys-Pro oligopeptide.

The present invention also provides a preparation method of quaternary water-soluble quantum dots, which is realized by the following steps:

Step 1, adding an aqueous solution containing a coating agent with a substance concentration of 0.01 to 0.6 mol/L into the mixed aqueous solution containing silver salt, indium salt and gallium salt and stirring uniformly to obtain a precursor solution;

Among them, the ratio of the molar amount of indium ion and gallium ion in the mixed aqueous solution containing silver salt, indium salt and gallium salt to the molar amount of silver ion is 1:(0.05～1); The ratio of the sum of the molar amounts of indium ions, gallium ions and silver ions in the mixed aqueous solution of the salt to the molar amount of the coating agent in the aqueous solution containing the coating agent is 1: (6-15); containing silver salt, indium salt The substance concentration of silver ions in the mixed aqueous solution of gallium salt is 0.01～0.15mol/L, the substance concentration of indium ions is 0.01～0.15mol/L, and the substance concentration of gallium ions is 0.01～0.15mol/L The amount concentration of the substance containing the coating agent in the coating agent aqueous solution is 0.01 to 0.6 mol/L; the silver salt is at least one of silver nitrate and silver acetate; the indium salt is indium nitrate, indium acetate and indium chloride. At least one of gallium salt is at least one of gallium nitrate, gallium sulfate and gallium chloride.

Step 2, adding sodium hydroxide solution to the precursor solution obtained in step 1 to adjust the pH value to 8-10.5 to obtain an alkaline precursor solution;

Step 3, adding an aqueous solution containing a sulfur source with a concentration of 0.01 to 0.15 mol/L to the alkaline precursor solution obtained in step 2 and stirring evenly to obtain a mixed aqueous solution containing the alkaline precursor and the sulfur source; The ratio of the sum of the molar amounts of indium ions, gallium ions, and silver ions in the precursor to the molar amount of sulfur in the sulfur source solution is 1: (1 to 20); the amount of the substance containing sulfur in the sulfur source solution The concentration is 0.01-0.15mol/L; the sulfur source is at least one of thioacetamide, thiourea and sodium sulfide.

Step 4, performing step-by-step hydrothermal treatment on the mixed aqueous solution containing the alkaline precursor and the sulfur source obtained in the step 3 to obtain quaternary water-soluble quantum dots (AgGaInS quantum dots coated with a surface coating agent); wherein The specific method of this step is as follows: heating the mixed aqueous solution of the alkaline precursor and the sulfur source to 60-80°C, at a constant temperature of 30-50min, then heating it to 110-120°C, at a constant temperature of 120-240min, cooling and centrifuging to obtain Quaternary water-soluble quantum dots (AgGaInS quantum dots coated with surface coating agent).

The quaternary water-soluble quantum dots obtained in the embodiment of the present invention are mostly used as fluorescent probes; the fluorescent probes are mainly used in the fields of optoelectronics, biology and medicine.

Compared with the quantum dots obtained by the existing one-step hydrothermal method, the quantum dots obtained by the present invention have very high crystallinity, a very uniform size distribution, and a wide adjustable range of fluorescence peaks. And between 450-750 nm, the fluorescence quantum yield is as high as more than 25%; in addition, the present invention can be well applied to optoelectronic devices and biological markers by selecting oligopeptides containing biologically active macromolecules as surface coating agents.

Example 1

A preparation method of quaternary water-soluble quantum dots, the method is realized by the following steps:

Step 1, respectively mix and stir 5ml 0.02mol/L silver nitrate aqueous solution, 1mL 0.05mol/L indium nitrate aqueous solution, and 6mL 0.02mol/L gallium nitrate aqueous solution, and then add 1.5mL 0.2mol/L Glu- Cys-Pro oligopeptide aqueous solution and 4.5mL 0.1mol/L sodium citrate aqueous solution are mixed to form a coating agent aqueous solution and stirred evenly to obtain a precursor solution;

Step 2, adding sodium hydroxide to the precursor solution obtained in step 1 to adjust the pH to 9 to obtain an alkaline precursor solution;

Step 3, adding 7.5 mL of an aqueous solution of 0.1 mol/L thioacetamide to the alkaline precursor solution obtained in step 2 and stirring evenly to obtain a mixed aqueous solution containing the alkaline precursor and thioacetamide;

Step 4, transfer the mixed aqueous solution containing the alkaline precursor and thioacetamide obtained in step 3 into an autoclave, heat to 60 ° C and keep constant temperature for 30 min, then heat to 110 ° C and keep constant temperature for 120 min, cool, and then use excess ethanol Centrifuge to obtain a precipitate, which is a quaternary water-soluble quantum dot (ie, AgInGaS quantum dot coated with a surface coating agent).

Example 2

A preparation method of quaternary water-soluble quantum dots, the method is realized by the following steps:

Step 1, respectively mix and stir 5ml 0.02mol/L silver nitrate aqueous solution, 1mL 0.05mol/L indium nitrate aqueous solution, and 6mL 0.02mol/L gallium sulfate aqueous solution, and then add 1.5mL 0.2mol/L Glu- Cys-Pro oligopeptide aqueous solution and 4.5mL 0.1mol/L sodium citrate aqueous solution are mixed to form a coating agent aqueous solution and stirred evenly to obtain a precursor solution;

Step 2, adding sodium hydroxide with a concentration of 1 mol/mL to the precursor solution obtained in step 1 to adjust the pH to 9 to obtain an alkaline precursor solution;

Step 3, adding 15 mL of an aqueous solution of 0.05 mol/L thiourea to the alkaline precursor solution obtained in step 2 and stirring to obtain a mixed aqueous solution containing the alkaline precursor and thiourea;

In step 4, the mixed aqueous solution containing the alkaline precursor and thiourea obtained in step 3 is transferred into an autoclave, heated to 60 ° C and kept at a constant temperature for 30 min, then heated to 110 ° C and kept at a constant temperature for 130 min, cooled, and then centrifuged with excess ethanol, A precipitate was obtained, which was a quaternary water-soluble quantum dot (ie, AgInGaS quantum dot coated with a surface capping agent).

Example 3

A preparation method of quaternary water-soluble quantum dots, the method is realized by the following steps:

Step 1, respectively mix and stir 5ml 0.02mol/L silver nitrate aqueous solution, 1.2mL 0.05mol/L, indium nitrate aqueous solution, and 7.5mL 0.02mol/L gallium nitrate aqueous solution, and then add 8mL 0.05mol/L Glu -The coating agent aqueous solution formed by mixing the Cys-Pro oligopeptide aqueous solution and the 2.65 mL 0.2 mol/L sodium citrate aqueous solution and stirring evenly to obtain the precursor solution;

Step 2, adding sodium hydroxide with a concentration of 1 mol/mL to the precursor solution obtained in step 1 to adjust the pH to 9 to obtain an alkaline precursor solution;

Step 3, adding 10.33 mL of an aqueous solution of 0.09 mol/L sodium sulfide to the alkaline precursor solution obtained in step 2 and stirring evenly to obtain a mixed aqueous solution containing the alkaline precursor and sodium sulfide;

Step 4, transfer the mixed aqueous solution containing the alkaline precursor and sodium sulfide obtained in step 3 into an autoclave, heat to 60°C and hold at constant temperature for 30min, then heat to 110°C and hold at constant temperature for 130min, cool, and then centrifuge with excess ethanol, A precipitate was obtained, which was a quaternary water-soluble quantum dot (ie, AgInGaS quantum dot coated with a surface capping agent).

Example 4

A preparation method of quaternary water-soluble quantum dots, the method is realized by the following steps:

Step 1, respectively mix and stir 2.5ml 0.04mol/L silver nitrate aqueous solution, 1.4mL 0.05mol/L indium nitrate aqueous solution, and 10mL 0.02mol/L gallium chloride aqueous solution, and then add 1mL 0.4mol/L Glu -The coating agent aqueous solution formed by mixing the Cys-Pro oligopeptide aqueous solution and the 4.5 mL 2.7 mol/L sodium citrate aqueous solution and stirring evenly to obtain the precursor solution;

Step 2, adding sodium hydroxide with a concentration of 1 mol/mL to the precursor solution obtained in step 1 to adjust the pH to 9 to obtain an alkaline precursor solution;

Step 3, adding 10.1 mL of an aqueous solution of 0.11 mol/L thioacetamide to the alkaline precursor solution obtained in step 2 and stirring evenly to obtain a mixed aqueous solution containing the alkaline precursor and thioacetamide;

Step 4, transfer the mixed aqueous solution containing the alkaline precursor and thioacetamide obtained in step 3 into an autoclave, heat to 60°C and keep the temperature constant for 30min, then heat to 110°C and keep the constant temperature for 130min, cool, and then use excess ethanol Centrifuge to obtain a precipitate, which is a quaternary water-soluble quantum dot (ie, AgInGaS quantum dot coated with a surface coating agent).

Example 5

A preparation method of quaternary water-soluble quantum dots, the method is realized by the following steps:

Step 1, respectively mix and stir 1ml 0.1mol/L silver nitrate aqueous solution, 1.6mL 0.05mol/L indium nitrate aqueous solution, and 15mL 0.02mol/L gallium sulfate aqueous solution, and then add 2mL 0.3mol/L Glu-Cys -The coating agent aqueous solution formed by mixing the Pro oligopeptide aqueous solution and the 4.5 mL 2.64 mol/L sodium citrate aqueous solution and stirring evenly to obtain the precursor solution;

Step 2, adding sodium hydroxide with a concentration of 1 mol/mL to the precursor solution obtained in step 1 to adjust the pH to 9 to obtain an alkaline precursor solution;

Step 3, adding 9.6 mL of an aqueous solution of 0.15 mol/L thioacetamide to the alkaline precursor solution obtained in step 2 and stirring evenly to obtain a mixed aqueous solution containing the alkaline precursor and thioacetamide;

Step 4, transfer the mixed aqueous solution containing the alkaline precursor and thioacetamide obtained in step 3 into an autoclave, heat to 60°C and keep the temperature constant for 30min, then heat to 110°C and keep the constant temperature for 130min, cool, and then use excess ethanol Centrifuge to obtain a precipitate, which is a quaternary water-soluble quantum dot (ie, AgInGaS quantum dot coated with a surface coating agent).

Quantum dot performance testing experiment:

The morphology of the quantum dots obtained in Examples 1 to 5 was observed by high-resolution transmission electron microscopy, as shown in Figure 2. It can be seen from Figure 2 that the size of the quantum dots is about 3 nm; the observed diffraction The stripes are very clear, indicating that the crystalline quality of the product is very high and there are few defects. This results in high fluorescence quantum yields for the quantum dots of the present invention, as described below.

The quantum dots obtained in Examples 1 to 5 were measured by a fluorescence spectrometer. The measurement results are shown in Figure 3. It can be seen from Figure 3 that the emission wavelengths of the quantum dots are 525 nm, 545 nm, 562 nm, 573 nm and 605 nm, respectively. , which shows that by changing the parameters of the present invention, products with different emission wavelengths can be obtained; in addition, it was observed that the size of the quantum dots obtained in Examples 1 to 5 did not change significantly, which indicates that the change in emission wavelength is not due to the change in size. Yes, this is the obvious difference between the quantum dots of the present invention and the traditional binary quantum dots.

The fluorescence quantum yields of the quantum dots obtained in Examples 1 to 5 were detected, and the detection results were shown in Figure 4. As can be seen from Figure 4, the quantum yields were 23%, 26%, 33%, 28% and 35%, both greater than 20%.

The quantum dots obtained in Examples 1 to 5 were tested for cytotoxicity using methods known in the field of life sciences. The test results are shown in Figure 5. It can be seen from Figure 5 that all the synthesized quantum dots were incubated for normal cells48 The survival rate after an hour is more than 95%, and the toxicity is extremely small. For the biological field, it can be called non-toxic quantum dots.

It can be seen that the quantum dots obtained by the embodiments of the present invention have good optical properties and biocompatibility, and have good application prospects in the fields of optoelectronics, life sciences and medicine.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention.

Claims (7)

1. a quaternary water-soluble quantum dot, is characterized in that, it comprises the core of AgGaInS and the coating agent that is coated on the core surface of AgGaInS, and described coating agent is composed of glutathione analog and sodium citrate composition, the glutathione analog is a Glu-Cys-Pro oligopeptide. 2. the preparation method of a kind of quaternary water-soluble quantum dots as claimed in claim 1, is characterized in that, this method realizes by following steps: Step 1, adding an aqueous solution containing a coating agent to the mixed aqueous solution containing silver salt, indium salt and gallium salt and stirring uniformly to obtain a precursor solution; Step 2, adjusting the pH value of the precursor solution obtained in the step 1 to 8-10.5 to obtain an alkaline precursor solution; Step 3, adding an aqueous solution containing a sulfur source to the alkaline precursor solution obtained in the step 2 and stirring evenly to obtain a mixed aqueous solution containing the alkaline precursor and the sulfur source; Step 4, performing step-by-step hydrothermal treatment on the mixed aqueous solution containing the alkaline precursor and the sulfur source obtained in the step 3 to obtain quaternary water-soluble quantum dots. 3 . The preparation method of a quaternary water-soluble quantum dot according to claim 2 , wherein in the step 1, indium ions and gallium ions in the mixed aqueous solution containing silver salts, indium salts and gallium salts The ratio of the molar amount of ions to the molar amount of silver ions is 1: (0.05～1); the molar amount of indium ions, gallium ions and silver ions in the mixed aqueous solution containing silver salt, indium salt and gallium salt The ratio to the molar amount of the coating agent in the aqueous solution containing the coating agent is 1:(6-15). 4. The preparation method of a quaternary water-soluble quantum dot according to claim 3, characterized in that, in the step 1, the material containing silver ions in the mixed aqueous solution containing silver salt, indium salt and gallium salt The mass concentration is 0.01-0.15mol/L, the mass concentration of the indium ion substance is 0.01～0.15mol/L, and the mass concentration of the gallium ion substance is 0.01～0.15mol/L; The substance concentration of the agent is 0.01 to 0.6 mol/L. 5. The preparation method of a quaternary water-soluble quantum dot according to claim 4, wherein in the step 1, the silver salt is at least one of silver nitrate and silver acetate; the indium The salt is at least one of indium nitrate, indium acetate, and indium chloride; the gallium salt is at least one of gallium nitrate, gallium sulfate, and gallium chloride. 6 . The method for preparing a quaternary water-soluble quantum dot according to claim 5 , wherein in the step 3, the molar weight of indium ion, gallium ion and silver ion in the alkaline precursor is equal to 6 . The ratio with the molar amount of elemental element sulfur in the aqueous solution containing sulfur source is 1:(1～20); the amount concentration of element elemental sulfur in the aqueous solution of sulfur source is 0.01～0.15mol/L; the source of sulfur is sulfur At least one of acetamide, thiourea, and sodium sulfide. 7. the preparation method of a kind of quaternary water-soluble quantum dots according to any one of claim 2-6, it is characterized in that, in described step 4, the specific method is: described containing alkaline precursor and sulfur source The mixed aqueous solution is heated to 60～80℃, constant temperature is 30～50min, then heated to 110～120℃, constant temperature is 120～240min, cooled and centrifuged to obtain quaternary water-soluble quantum dots.

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