Dual-ligand construction of long-term high-luminescence water-soluble quantum dot fluorescent probe
Patent Information
- Application Number
- CN202410556754.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-07
- Publication Date
- 2025-01-10
- Estimated Expiration
- 2044-05-07
AI Technical Summary
During the ligand exchange, silica coating, and amphiphilic organic polymer coating processes of existing quantum dot fluorescent probes, the fluorescence quantum efficiency decreases and the stability is insufficient, resulting in poor detection results, complex steps, and high costs.
Using a double ligand construction method, by synthesizing Cd(AC)2-OAm precursor and CdSe quantum dots, combined with surfactants, the quantum dots can be simply transferred to the aqueous phase, and purified by ultrasound and centrifugation to improve fluorescence efficiency and stability. sex.
It significantly improves the fluorescence efficiency of quantum dots, maintains a high luminescence state for more than a month, simplifies the operation steps, solves the problem of gradual decline in fluorescence, and improves the detection sensitivity of the probe.
Smart Images
Figure CN118440689A8_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of quantum dot synthesis, in particular to the construction of long-term high-luminescence water-soluble quantum dot fluorescent probes with double ligands. Background Art
[0002] Quantum dots, also known as nanocrystals or artificial atoms, are quasi-zero-dimensional nanoparticles composed of II-VI or III-V elements. Usually, the size of quantum dots in three dimensions is less than 100 nanometers (nm). Due to the quantum confinement effect, the electrons and holes in quantum dots have discrete energy level structures and can emit fluorescence when stimulated.
[0003] Fluorescent probes refer to a class of fluorescent molecules that have characteristic fluorescence in the ultraviolet-visible-near infrared region, and whose fluorescence properties (excitation and emission wavelengths, intensity, lifetime, polarization, etc.) can change sensitively with the properties of the environment, such as polarity, refractive index, viscosity, etc.
[0004] There are three common ways to modify the water-soluble quantum dots in the prior art:
[0005] (1) Ligand exchange: replacing surface ligands with hydrophilic ligands;
[0006] (2) Silica coating: The hydrophilic groups on the surface of silica give quantum dots water solubility, good photostability and thermal stability, and the ability to bind to organisms;
[0007] (3) Amphiphilic organic polymer coating: The hydrophobic end of the polymer is combined with the surface of the oily quantum dots, and the hydrophilic end of the polymer enables the quantum dots to be dispersed in water.
[0008] The above-mentioned prior art has the following problems in practical application:
[0009] (1) During the ligand exchange process, the physical and chemical states of the atoms on the surface of the quantum dots are inevitably changed, which leads to a significant reduction in the fluorescence quantum efficiency of the quantum dots. As a result, the detection effect as a probe is poor due to the decrease in quantum efficiency.
[0010] (2) The process of coating with silica will lead to a decrease in fluorescence quantum efficiency and agglomeration and sedimentation of quantum dots, thus affecting the practical application of the probe. In addition, this method has complex steps and leads to high costs.
[0011] In combination with the above, the stability of quantum dots is improved to a low level during the coating process with amphiphilic organic polymers. At the same time, during the phase transfer process, the quantum dots will undergo energy transfer, resulting in a decrease in fluorescence intensity, which in turn affects the effect of detection as a probe.
[0012] To sum up the above problems, we provide a dual ligand to construct a long-term highly luminescent water-soluble quantum dot fluorescent probe. Summary of the invention
[0013] The purpose of the present invention is to provide a dual-ligand structured long-term high-luminescence water-soluble quantum dot fluorescent probe to solve the above-mentioned problems.
[0014] To achieve the above object, the present invention provides the following technical solutions:
[0015] The dual-ligand construction of long-term high-luminescence water-soluble quantum dot fluorescent probes includes the following steps:
[0016] Step S1, synthesis of Cd(AC)2-OAm precursor: 571 mg (2.5 mmol) of cadmium acetate Cd(AC)2 powder and 3 ml of oleylamine (OAm) were mixed in a 5 ml vial, and the mixture was vigorously shaken for 5 minutes and then slightly heated, and the shaking was continued until the solid was dissolved, thereby obtaining CdOAm in the form of a clear solution, wherein CdOAm was the first ligand;
[0017] Step S2, preparation of CdSe precursor: under the protection of argon atmosphere, trioctyl phosphoric acid (TOP) was injected into selenium powder to prepare TOP-Se solution, which was then diluted with 1-octadecene (ODE) to a concentration of 1.5 M, and stirred for more than 12 hours to ensure complete dissolution, and finally stored in a sealed flask;
[0018] Step S3, synthesis of CdSe quantum dots: 46 mg (0.4 mmol) of Cd(AC)2 powder and 317 μl of oleic acid were mixed in a 10 ml vial, shaken vigorously for 5 minutes and then slightly heated until the solid dissolved to obtain cadmium oleate in the form of a clear solution, then, 500 μl (4 mmol) of (Z)-9-octadecenoic acid amide (OLAm) was added at room temperature, and then 2 ml of ODE was added as a solvent, and the mixture was heated at 260°C for 3 minutes, and 0.8 ml of TOPSe solution was quickly injected while hot, and the reaction was continued at 260°C for a given period of time, and then taken out and cooled to room temperature. The prepared quantum dot solution contained 0D / 1DNCs, which was mixed with a solution containing n-hexane and ethanol (1:4, v / v), centrifuged at 4000 rpm for 5 min, and after purification three times, the precipitate was dispersed in dichloromethane for further characterization;
[0019] Step S4, preparation of water-soluble quantum dots: take 500 μl of the quantum dot solution dispersed in dichloromethane, add 5 μl of the CdOAm precursor solution, react for a period of time, evaporate the dichloromethane completely, add an aqueous solution of a suitable surfactant, wherein the surfactant is the second ligand, ultrasonicate for 5 minutes in an ultrasonic machine, and then centrifuge at a speed of 4000 rpm for 1 minute, and the supernatant is the water-soluble quantum dots;
[0020] Step S5, preparing a simple water-soluble quantum dot test paper: cut the filter paper into two rectangular sections, similar to pH test paper, put the filter paper into the newly prepared stable luminescent water-soluble CdSe quantum dot solution, soak for a period of time, take it out and dry it in an oven, use a glass rod to dip the above solution and drop it on the test paper, and observe it under ultraviolet light after drying;
[0021] Step S6, detection of metal ions in CdSe quantum dots and / or detection of antibiotic tetracycline: 500ul of metal ions are taken and titrated on the quantum dot test paper, and the quenching of quantum dots can be observed immediately on the test paper.
[0022] Preferably, in the step S1, during the synthesis of the Cd(AC)2-OAm precursor, the ratio of selenium to trioctyl phosphate (TOP) is 1:1.2.
[0023] Preferably, in step S2, Cd(AC)2-OAm may also be Cd(AC)2-OLAm.
[0024] Preferably, in the preparation process of water-soluble quantum dots in step S4, the aqueous solution may be cetyltrimethylammonium bromide (CTAB).
[0025] Preferably, in the step S4 of preparing the water-soluble quantum dots, the aqueous solution may also be didecyldimethylammonium bromide (DDAB).
[0026] Preferably, in the preparation process of water-soluble quantum dots in step S4, the aqueous solution may also be sodium dodecyl sulfate (SDS).
[0027] Preferably, in the preparation process of water-soluble quantum dots in step S4, the aqueous solution may also be gelatin.
[0028] Compared with the prior art, the present invention has the following beneficial effects:
[0029] The present invention transfers the oil phase quantum dots to the water phase by simply adding a bi-amphiphilic substance to the surface, and the fluorescence efficiency is improved compared to the original quantum dots, and high luminescence can be maintained for more than one month. The overall operation steps are simple, which solves the problem of the prior art that the fluorescence gradually decreases or even disappears in a short period of time. BRIEF DESCRIPTION OF THE DRAWINGS
[0030] Figure 1 It is a schematic diagram of the process of the present invention; DETAILED DESCRIPTION
[0031] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0032] Embodiment 1:
[0033] The dual ligands construct a long-term high-luminescence water-soluble quantum dot fluorescent probe. The following is a detailed introduction to the above production and its application:
[0034] Step S1, synthesis of Cd(AC)2-OAm precursor: 571 mg (2.5 mmol) of cadmium acetate Cd(AC)2 powder and 3 ml of oleylamine (OAm) were mixed in a 5 ml vial, and the mixture was vigorously shaken for 5 minutes and then slightly heated, and the shaking was continued until the solid was dissolved, thereby obtaining CdOAm in the form of a clear solution, wherein CdOAm was the first ligand;
[0035] Step S2, preparation of CdSe precursor: under the protection of argon atmosphere, trioctyl phosphoric acid (TOP) was injected into selenium powder to prepare TOP-Se solution, which was then diluted with 1-octadecene (ODE) to a concentration of 1.5 M, and stirred for more than 12 hours to ensure complete dissolution, and finally stored in a sealed flask;
[0036] Step S3, synthesis of CdSe quantum dots: 46 mg (0.4 mmol) of Cd(AC)2 powder and 317 μl of oleic acid were mixed in a 10 ml vial, shaken vigorously for 5 minutes and then slightly heated until the solid dissolved to obtain cadmium oleate in the form of a clear solution, then, 500 μl (4 mmol) of (Z)-9-octadecenoic acid amide (OLAm) was added at room temperature, and then 2 ml of ODE was added as a solvent, and the mixture was heated at 260°C for 3 minutes, and 0.8 ml of TOPSe solution was quickly injected while hot, and the reaction was continued at 260°C for a given period of time, and then taken out and cooled to room temperature. The prepared quantum dot solution contained 0D / 1DNCs, which was mixed with a solution containing n-hexane and ethanol (1:4, v / v), centrifuged at 4000 rpm for 5 min, and after purification three times, the precipitate was dispersed in dichloromethane for further characterization;
[0037] Step S4, preparation of water-soluble quantum dots: take 500 μl of the quantum dot solution dispersed in dichloromethane, add 5 μl of the CdOAm precursor solution, react for a period of time, evaporate the dichloromethane completely, add an aqueous solution of a suitable surfactant, wherein the surfactant is the second ligand, ultrasonicate for 5 minutes in an ultrasonic machine, and then centrifuge at a speed of 4000 rpm for 1 minute, and the supernatant is the water-soluble quantum dots;
[0038] Step S5, preparing a simple water-soluble quantum dot test paper: cut the filter paper into two rectangular sections, similar to pH test paper, put the filter paper into the newly prepared stable luminescent water-soluble CdSe quantum dot solution, soak for a period of time, take it out and dry it in an oven, use a glass rod to dip the above solution and drop it on the test paper, and observe it under ultraviolet light after drying;
[0039] Step S6, detection of metal ions in CdSe quantum dots and / or detection of antibiotic tetracycline: 500ul of metal ions are taken and titrated on the quantum dot test paper, and the quenching of quantum dots can be observed immediately on the test paper.
[0040] Furthermore, in step S2, the ratio of selenium to trioctyl phosphate (TOP) is 1:1.2.
[0041] Embodiment 2:
[0042] Based on Example 1, the present invention provides a further solution: in the step S1, during the synthesis of the Cd(AC)2-OAm precursor, Cd(AC)2-OAm can also be Cd(AC)2-OLAm.
[0043] Based on Example 1, the present invention provides a further solution: in the preparation process of the water-soluble quantum dots in step S4, the aqueous solution can be cetyltrimethylammonium bromide (CTAB).
[0044] Based on Example 1, the present invention provides a further solution: in the preparation process of the water-soluble quantum dots in step S4, the aqueous solution can also be didecyl dimethyl ammonium bromide (DDAB).
[0045] Based on Example 1, the present invention provides a further solution: in the preparation process of water-soluble quantum dots in step S4, the aqueous solution can also be sodium dodecyl sulfate (SDS).
[0046] Based on Example 1, the present invention provides a further solution: in the preparation process of water-soluble quantum dots in step S4, the aqueous solution can also be gelatin.
[0047] In summary: the present invention promotes the long-term and efficient luminescence of quantum dots through the operations of step S1 and step S3, so that they have higher fluorescence efficiency and are promoted to be used in actual detection, that is, the brighter the better, the more sensitive, and the lower limit of the detectable substance is, which solves the problem of low fluorescence intensity and only luminescence in a short time in the prior art.
[0048] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.
Claims
1. Double ligands to construct long-term high-luminescence water-soluble quantum dot fluorescent probes, characterized in that: The following steps are involved: Step S1, synthesis of Cd(AC)2-OAm precursor: 571 mg of cadmium acetate Cd(AC)2 powder and 3 ml of oleylamine OAm were mixed in a 5 ml vial, vigorously shaken for 5 minutes and then slightly heated, and continued to shake until the solid dissolved, thereby obtaining CdOAm in the form of a clear solution; Step S2, preparation of CdSe precursor: under the protection of argon atmosphere, inject trioctyl phosphate TOP into selenium powder to prepare TOP-Se solution, then dilute with 1-octadecene ODE to a concentration of 1.5M, continue stirring for more than 12 hours to ensure complete dissolution, and finally store in a sealed flask; Step S3, synthesis of CdSe quantum dots: 46 mg Cd(AC)2 powder and 317 μl oleic acid were mixed in a 10 ml vial, shaken vigorously for 5 minutes and then slightly heated until the solid dissolved to obtain cadmium oleate in the form of a clear solution, then, 500 μl (Z)-9-octadecenoic acid amide OLAm was added at room temperature, and then 2 ml ODE was added as a solvent, and the mixture was heated at 260°C for 3 minutes, and 0.8 ml TOPSe solution was quickly injected while hot, and the reaction was continued at 260°C for a given period of time, and then taken out and cooled to room temperature. The prepared quantum dot solution contained 0D / 1DNCs, which was mixed with a solution containing n-hexane and ethanol, and centrifuged at 4000 rpm for 5 minutes. After purification three times, the precipitate was dispersed in dichloromethane for further characterization; Step S4, preparation of water-soluble quantum dots: 500 μl of the quantum dot solution dispersed in dichloromethane was taken, and 5 μl of the CdOAm precursor solution was added. After a period of reaction, the dichloromethane was completely evaporated, and then an aqueous solution of a suitable surfactant was added. The mixture was ultrasonicated in an ultrasonic machine for 5 minutes, and then centrifuged at 4000 rpm for 1 minute. The supernatant was the water-soluble quantum dots. Step S5, preparing a simple water-soluble quantum dot test paper: cut the filter paper into two rectangular sections, similar to pH test paper, put the filter paper into the newly prepared stable luminescent water-soluble CdSe quantum dot solution, soak for a period of time, take it out and dry it in an oven, use a glass rod to dip the above solution and drop it on the test paper, and observe it under ultraviolet light after drying; Step S6, detection of metal ions in CdSe quantum dots and / or detection of antibiotic tetracycline: 500ul of metal ions are taken and titrated on the quantum dot test paper, and the quenching of quantum dots can be observed immediately on the test paper.
2. The dual-ligand long-term high-luminescence water-soluble quantum dot fluorescent probe according to claim 1, characterized in that: In the step S2, the ratio of selenium to trioctyl phosphate TOP is 1:1.
2.
3. The dual-ligand long-term high-luminescence water-soluble quantum dot fluorescent probe according to claim 1, characterized in that: In the step S1, during the synthesis of the Cd(AC)2-OAm precursor, Cd(AC)2-OAm may also be Cd(AC)2-OLAm.
4. The dual-ligand constructed long-term high-luminescence water-soluble quantum dot fluorescent probe according to claim 1, characterized in that: In the step S4 of preparing water-soluble quantum dots, the aqueous solution may be hexadecyltrimethylammonium bromide (CTAB).
5. The dual-ligand constructed long-term high-luminescence water-soluble quantum dot fluorescent probe according to claim 1, characterized in that: In the step S4 of preparing the water-soluble quantum dots, the aqueous solution may also be didecyl dimethyl ammonium bromide DDAB.
6. The dual-ligand constructed long-term high-luminescence water-soluble quantum dot fluorescent probe according to claim 1, characterized in that: In the preparation process of water-soluble quantum dots in step S4, the aqueous solution can also be sodium dodecyl sulfate (SDS).
7. The dual-ligand constructed long-term high-luminescence water-soluble quantum dot fluorescent probe according to claim 1, characterized in that: In the process of preparing water-soluble quantum dots in step S4, the aqueous solution may also be gelatin.