CN108659814A - A kind of quaternary water-soluble quantum dot and its preparation method and application - Google Patents

Abstract

The invention discloses 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; the invention also discloses a preparation method and application of the quantum dot. The quantum dots obtained by the step-by-step hydrothermal method in the present invention have high crystallinity, uniform size distribution, a wide adjustable range of fluorescence peaks between 450 and 750 nm, and a fluorescence quantum yield as high as 25% or more; in addition, the present invention selects Oligopeptides containing biologically active macromolecules as surface coating agents can be well applied in optoelectronic 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 its preparation method and application.

Background technique

Semiconductor nanocrystals (Nanocrystals, NCs), also known as quantum dots (Quantum dots, QDs), are a semiconductor material that is limited in three dimensions of space; quantum dots have been studied so far, and various types of structures have emerged and materials; from the structural division, there are core-shell structure, alloy structure, heterostructure, etc.; in terms of material types, there are II-VI groups (such as CdS), III-V groups (such as InP), etc.; these types of quantum It has been developed for a long time, so the synthesis process is very mature, but it contains Class A 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 a high light absorption coefficient, good biocompatibility and comparative Strong defect tolerance, so it has attracted people's attention; 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 application in luminescent materials and Applications in the field of biomarkers.

Contents 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 implemented 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 agent consists of glutathione analogs and sodium citrate.

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

Step 1, adding an aqueous solution containing a coating agent to a mixed aqueous solution containing silver salt, indium salt, and gallium salt and stirring evenly 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 step 2 and stirring evenly to obtain a mixed aqueous solution containing an alkaline precursor and a sulfur source;

In step 4, the mixed aqueous solution containing the alkaline precursor and the sulfur source obtained in step 3 is subjected to step-by-step hydrothermal treatment 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 sum of the molar weights of indium ions and gallium ions to the molar weight of silver ions in the mixed aqueous solution containing silver salts, indium salts, and gallium salts is 1:(0.05～1) ; The molar sum of the molar weight sum of indium ion, gallium ion, silver ion in the mixed aqueous solution that contains silver salt, indium salt, gallium salt and the ratio of the molar weight of the coating agent in the aqueous solution that contains coating agent is 1:( 6~15).

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

Preferably, the specific method in step 4 is: heating the mixed aqueous solution containing the alkaline precursor and the sulfur source to 60-80°C for 30-50 minutes, then heating to 110-120°C for 120-240 minutes , cooled and centrifuged to obtain quaternary water-soluble quantum dots.

The quaternary water-soluble quantum dot of the present invention is mostly used as a fluorescent probe; the fluorescent probe is mainly used in the fields of optoelectronics, biology and medicine.

Compared with the prior art, the crystallinity of the quantum dots obtained by the step-by-step hydrothermal method in the present invention is very high, the size distribution is very uniform, the fluorescence peak can be adjusted in a wide range between 450-750nm, and the fluorescence quantum yield is as high as 25 In addition, the present invention can be well applied in optoelectronic devices and biomarkers by selecting oligopeptides containing biologically active macromolecules as surface coating agents.

Description of drawings

Fig. 1 is the synthesizing schematic diagram of the quaternary water-soluble quantum dot provided by the embodiment of the present invention;

Fig. 2 is the high-resolution transmission electron microscope picture of the quaternary water-soluble quantum dot provided by the embodiment of the present invention;

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

Fig. 4 is a schematic diagram of the fluorescence quantum yield of the quaternary water-soluble quantum dot provided by 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 by the embodiment of the present invention.

Detailed ways

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

Symbols and formulas used in the present invention have meanings known in the art. Specifically, AgGaInS represents an alloy composed of silver, indium, gallium and sulfur; Glu-Cys-Pro oligopeptide is glutamic acid-cysteine-proline tripeptide; Glu-Cys-Pro oligopeptides are biocompatible ligands for surface modification that complex to metal ions on the surface. It should be understood that although they are referred to herein as surface coating agents, it is not intended to limit their use in the methods of the present invention to merely surface coating functions.

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 consists of glutathione analogs and sodium citrate Composition, glutathione analogs are Glu-Cys-Pro oligopeptides.

The present invention also provides a preparation method of quaternary water-soluble quantum dots, which is realized through 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 to the mixed aqueous solution containing silver salt, indium salt, and gallium salt and stirring evenly to obtain a precursor solution;

Wherein, the ratio of the molar weight sum of indium ion and gallium ion to the molar weight of silver ion in the mixed aqueous solution containing silver salt, indium salt and gallium salt is 1: (0.05～1); The molar ratio of the sum of the molar weights of indium ions, gallium ions, and silver ions in the mixed aqueous solution of the salt to the molar weight of the coating agent in the aqueous solution containing the coating agent is 1: (6-15); containing silver salts, indium salts , The molar concentration of silver ions in the mixed aqueous solution of gallium salts is 0.01-0.15 mol/L, the molar concentration of indium ions is 0.01-0.15 mol/L, and the molar concentration of gallium ions is 0.01-0.15 mol/L The concentration of the substance containing the coating agent in the aqueous solution of the coating agent is 0.01 to 0.6mol/L; the silver salt is at least one of silver nitrate and silver acetate; the indium salt is indium nitrate, indium acetate, or indium chloride at least one of; the 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 an alkaline precursor and a sulfur source; wherein, the alkali The ratio of the sum of the molar weights of indium ions, gallium ions, and silver ions in the precursor to the molar weight of the sulfur element in the sulfur source solution is 1: (1 to 20); the amount of the substance containing the sulfur element 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 a step-by-step hydrothermal treatment on the mixed aqueous solution containing an alkaline precursor and a sulfur source obtained in step 3 to obtain a quaternary water-soluble quantum dot (AgGaInS quantum dot coated with a surface coating agent); wherein , the specific method of this step is: heating the mixed aqueous solution of the alkaline precursor and the sulfur source to 60-80°C, maintaining the temperature for 30-50 minutes, then heating to 110-120°C, maintaining the temperature for 120-240 minutes, cooling, and centrifuging to obtain Quaternary water-soluble quantum dots (AgGaInS quantum dots coated with a surface coating agent).

The quaternary water-soluble quantum dots obtained in the embodiments 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, very uniform size distribution, and a wide adjustable range of fluorescence peaks. And between 450-750nm, the fluorescence quantum yield is as high as 25%. In addition, the present invention can be well applied to photoelectric devices and biomarkers 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 through the following steps:

Step 1: Mix and stir 5ml of 0.02mol/L silver nitrate aqueous solution, 1mL of 0.05mol/L indium nitrate aqueous solution, and 6mL of 0.02mol/L gallium nitrate aqueous solution, and then add 1.5mL of 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 7.5mL of 0.1mol/L aqueous solution of 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 for 30 minutes, then heat to 110°C and keep the temperature for 120 minutes, 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 through the following steps:

Step 1, mix and stir 5ml 0.02mol/L silver nitrate aqueous solution, 1mL 0.05mol/L indium nitrate aqueous solution, 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 15mL of 0.05mol/L thiourea aqueous solution to the alkaline precursor solution obtained in step 2 and stirring evenly to obtain a mixed aqueous solution containing the alkaline precursor and thiourea;

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

Example 3

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

Step 1: Mix and stir 5ml of 0.02mol/L silver nitrate aqueous solution, 1.2mL of 0.05mol/L indium nitrate aqueous solution, and 7.5mL of 0.02mol/L gallium nitrate aqueous solution, and then add 8mL of 0.05mol/L Glu -Cys-Pro oligopeptide aqueous solution and 2.65mL 0.2mol/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 10.33mL of 0.09mol/L sodium sulfide aqueous solution 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 keep the temperature for 30 minutes, then heat to 110°C and keep the temperature for 130 minutes, cool, and centrifuge with excess ethanol, A precipitate is obtained, which is a quaternary water-soluble quantum dot (ie: AgInGaS quantum dot coated with a surface coating agent).

Example 4

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

Step 1, respectively mix 2.5ml 0.04mol/L silver nitrate aqueous solution, 1.4mL 0.05mol/L indium nitrate aqueous solution, 10mL 0.02mol/L gallium chloride aqueous solution and mix well, then add 1mL 0.4mol/L Glu -Cys-Pro oligopeptide aqueous solution and 4.5mL 2.7mol/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 10.1mL of 0.11mol/L aqueous solution of 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 for 30 minutes, then heat to 110°C and keep the temperature for 130 minutes, 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 through the following steps:

Step 1, respectively mix 1ml 0.1mol/L silver nitrate aqueous solution, 1.6mL 0.05mol/L indium nitrate aqueous solution, 15mL 0.02mol/L gallium sulfate aqueous solution and mix well, then add 2mL 0.3mol/L Glu-Cys -Pro oligopeptide aqueous solution and 4.5mL 2.64mol/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 9.6mL of 0.15mol/L aqueous solution of 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 for 30 minutes, then heat to 110°C and keep the temperature for 130 minutes, 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).

Performance testing experiment of quantum dots:

Adopt high-resolution transmission electron microscope to observe the morphology of the quantum dots that embodiment 1 to embodiment 5 obtain, as shown in Figure 2, can see from Figure 2, the size of quantum dot is about 3nm; Observed diffraction The stripes are very clear, indicating that the crystal quality of the product is very high and there are very few defects. This results in high fluorescence quantum yields for the quantum dots of the present invention, as described below.

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

The fluorescent quantum yields of the quantum dots obtained in Example 1 to Example 5 are detected, and the detection results are as shown in Figure 4. As can be seen from Figure 4, the quantum yields are 23%, 26%, 33%, respectively. 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 FIG. The survival rate after hours is above 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 using 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 (10)

1. A quaternary water-soluble quantum dot, characterized in that it includes a core of AgGaInS and a coating agent coated on the surface of the core of AgGaInS. 2. A quaternary water-soluble quantum dot according to claim 1, wherein the coating agent is composed of glutathione analogs and sodium citrate. 3. A preparation method of quaternary water-soluble quantum dots, characterized in that, the method is realized through the following steps: Step 1, adding an aqueous solution containing a coating agent to a mixed aqueous solution containing silver salt, indium salt, and gallium salt and stirring evenly 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 step 2 and stirring evenly to obtain a mixed aqueous solution containing an alkaline precursor and thioacetamide; In step 4, the mixed aqueous solution containing the alkaline precursor and thioacetamide obtained in step 3 is subjected to step-by-step hydrothermal treatment to obtain quaternary water-soluble quantum dots. 4. the preparation method of a kind of quaternary water-soluble quantum dot according to claim 3 is characterized in that, in described step 1, in the mixed aqueous solution that contains silver salt, indium salt, gallium salt, indium ion, gallium The ratio of the molar weight sum of ions to the molar weight of silver ions is 1:(0.05～1); the molar weight ratio of indium ions, gallium ions, and silver ions in the mixed aqueous solution containing silver salt, indium salt, and gallium salt The ratio of the sum to the molar amount of the coating agent in the aqueous solution containing the coating agent is 1:(6-15). 5. the preparation method of a kind of quaternary water-soluble quantum dot according to claim 4 is characterized in that, in described step 1, the material of silver ion in the mixed aqueous solution that contains silver salt, indium salt, gallium salt The molar concentration is 0.01-0.15mol/L, the molar concentration of indium ions is 0.01-0.15mol/L, and the molar concentration of gallium ions is 0.01-0.15mol/L; The concentration of the substance of the agent is 0.01-0.6 mol/L. 6. the preparation method of a kind of quaternary water-soluble quantum dot according to claim 5 is characterized in that, in described step 1, described silver salt is at least one in silver nitrate, silver acetate; 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. 7. the preparation method of a kind of quaternary water-soluble quantum dot according to claim 6 is characterized in that, in described step 3, the molar weight of indium ion, gallium ion, silver ion in described basic precursor The ratio of the sum to the molar amount of sulfur element in the sulfur source aqueous solution is 1:(1～20); the concentration of the sulfur element in the sulfur source aqueous solution is 0.01～0.15mol/L; the sulfur source is sulfur At least one of acetamide, thiourea, and sodium sulfide. 8. according to the preparation method of a kind of quaternary water-soluble quantum dot described in any one of claim 3-7, it is characterized in that, the specific method in the described step 4 is: the described containing alkaline precursor and sulfur source The mixed aqueous solution is heated to 60-80° C., kept at a constant temperature for 30-50 minutes, then heated to 110-120° C., kept at a constant temperature for 120-240 minutes, cooled and centrifuged to obtain quaternary water-soluble quantum dots. 9. The use of a quaternary water-soluble quantum dot according to any one of claims 1-2 as a fluorescent probe. 10. The use according to claim 9, characterized in that the fluorescent probe is used in the fields of optoelectronics, biology and medicine.