A method for preparing and applying a water-soluble quantum sheet fluorescent probe

Abstract

This invention belongs to the field of fluorescent probe preparation technology, specifically a method for preparing and applying a water-soluble quantum sheet fluorescent probe, comprising the following steps: Step 1: Disperse purified cadmium selenide quantum sheets in a hexane solution, add cadmium octanoate, and shake in a centrifuge tube for 10 min to obtain quantum sheets with cadmium octanoate as the surface; Step 2: Centrifuge the cadmium octanoate-surfaced quantum sheets at 6000 r / min for 3 min, and discard the supernatant; Step 3: Add a hexane solution, repeat steps 1 and 2, and place the obtained precipitate in an oven to dry at 40℃; Step 4: Add 1 mL of a 1% amphiphilic aqueous solution to the dried precipitate, and sonicate for 15 min to obtain a uniformly dispersed quantum sheet aqueous solution; This invention is water-soluble and can be directly synthesized in water, which is more conducive to practical applications. Furthermore, by adding ligands, the water-soluble quantum sheets of this invention can maintain fluorescence characteristics for about one month.

Description

Technical Field

[0001] This invention belongs to the field of fluorescent probe preparation technology, specifically a method for preparing and applying a water-soluble quantum sheet fluorescent probe. Background Technology

[0002] Water-soluble probes are probe molecules that can dissolve and remain stable in an aqueous phase. They typically possess specific chemical structures and can interact specifically with biomolecules or other targets, thereby providing important information about the target. Based on their structure and applications, water-soluble probes can be classified into various types, including fluorescent probes, chemiluminescent probes, and nuclear magnetic resonance probes.

[0003] Semiconductor nanocrystals are considered ideal fluorescent emission materials due to their spectral properties and long-term stability. Among them, quasi-two-dimensional semiconductor nanosheets, as a new generation of nanocrystal materials, have attracted much attention due to their unique physical properties. Compared with traditional quasi-spherical semiconductor nanocrystals (such as quantum dots), two-dimensional quantum sheets are synthesized through colloidal methods, allowing each particle to exhibit an integer atomic layer structure in thickness and extended states in both dimensions. This results in quantum sheets experiencing the same level of quantum confinement in the thickness direction, with highly consistent spectral properties between individual particles and the aggregate. Furthermore, quantum sheets exhibit superior properties such as high fluorescence quantum yield and large single-photon and two-photon absorption cross sections, making them promising for applications in multiplex fluorescently labeled biological systems. However, most cadmium chalcogenide quantum sheets are synthesized in organic solvents, while biological research environments typically require water-soluble materials. Although much research has been dedicated to improving fluorescence quantum yield and achieving aqueous phase transfer, the specific geometry of quantum sheets presents additional technical challenges during phase transfer. For example, ligand exchange is the most commonly used transfer strategy, but simple ligand exchange can easily damage the surface of the quantum sheet, leading to fluorescence quenching. In addition, exposed surfaces are susceptible to chemical corrosion, which further reduces fluorescence brightness.

[0004] In early studies of quantum sheet aqueous phase transfer, Lim et al. proposed a method using a combination of phospholipids, detergents, and membrane scaffold proteins to effectively encapsulate quantum sheets to suit their geometry. To maintain fluorescence performance, they grew a cadmium selenide (CdSe) shell on the exterior of the core of the cadmium selenide (CdSe) quantum sheet. While this method achieved a quantum yield of 4.3% in hexane, the quantum yield dropped to 1.6% in the aqueous phase. This protein encapsulation strategy endows quantum sheets with biological properties such as rapid cellular uptake, but its dependence on expensive protein materials limits the scalability for large-scale applications. Kechkeche et al. proposed a two-step ligand exchange method, first transferring the quantum sheet to the aqueous phase using small molecule ligands, and then forming a final coating by introducing a specially formulated water-soluble polymer. The advantage of this strategy lies in the customizability of the polymer, allowing for the introduction of various functional groups and improving the dispersibility of the quantum sheet in high-ionic-strength aqueous environments. However, the limitation of this method is its reliance on complex polymer design and a two-step operational process, increasing experimental complexity. To simplify the encapsulation and aqueous phase transfer of quantum sheets, Andreas Riedinger et al. developed a one-step strategy based on polymer coating. Specifically, this method utilizes dodecyl-grafted poly(isobutylene-alt-maleic acid), whose hydrophobic side chains bind to hydrophobic ligands on the quantum sheet surface through hydrophobic interactions. Meanwhile, the anhydride units hydrolyze in the aqueous phase to generate a large number of negatively charged carboxylic acid groups, significantly improving the aqueous stability of the quantum sheet. This strategy has attracted attention due to its simplicity, inexpensive and readily available starting materials, and good scalability. However, the polymer synthesis process in this method remains relatively complex and requires further optimization to meet the needs of practical applications.

[0005] However, the above-mentioned technologies still have some problems in practical applications:

[0006] 1. Lim et al. used a combination of phospholipids, detergents, and membrane scaffold proteins that matched the geometry of the quantum sheet to encapsulate them around the quantum sheet before transferring it to water; however, this encapsulation technique relies on expensive protein synthesis, which limits the scalability of the method.

[0007] 2. Kechkeche et al. used a two-step ligand exchange method. First, they used simple small molecule ligands to transfer the quantum sheet to the aqueous phase, and then attached a specially made water-soluble polymer as the final coating to disperse the quantum sheet in a high ionic strength aqueous environment. However, this method is complicated to operate, costly, and has low fluorescence efficiency and poor stability.

[0008] Therefore, a method for preparing and applying a water-soluble quantum sheet fluorescent probe is proposed to address the above problems. Summary of the Invention

[0009] (a) Technical problems to be solved

[0010] To address the shortcomings of existing technologies, this invention provides a method for preparing and applying a water-soluble quantum sheet fluorescent probe, thereby resolving the problems raised in the specification.

[0011] (II) Technical Solution

[0012] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing a water-soluble quantum sheet fluorescent probe, comprising the following steps:

[0013] Step 1: Disperse the purified cadmium selenide quantum sheet in n-hexane solution, add cadmium octanoate to it, and shake in a centrifuge tube for 10 min to obtain quantum sheet with cadmium octanoate on the surface;

[0014] Step 2: Centrifuge the quantum sheet with cadmium octanoate surface at 6000 r / min for 3 min and discard the supernatant;

[0015] Step 3: Add n-hexane solution, repeat steps 1 and 2, and then place the resulting precipitate in an oven to dry at 40°C.

[0016] Step 4: Add 1 mL of 1% amphiphilic aqueous solution to the dried precipitate and sonicate for 15 min to obtain a uniformly dispersed quantum sheet aqueous solution.

[0017] Preferably, in step 3, dichloromethane solution can be added to dissolve and transfer the precipitate before drying.

[0018] Preferably, in step 4, the aqueous solution of the amphiphilic substance is a sodium dodecyl sulfate solution.

[0019] The preferred method for preparing purified cadmium selenide quantum sheets is as follows:

[0020] After dispersing cadmium selenide quantum sheets in dichloromethane solvent, cadmium octanoate is added to obtain purified cadmium selenide quantum sheets.

[0021] The preparation method of cadmium octanoate is as follows:

[0022] Cadmium octate was prepared by dissolving 0.6 mmol of cadmium oxide in 3 mL of octanoic acid at 150 degrees Celsius to obtain a clear solution.

[0023] A water-soluble quantum sheet fluorescent probe is prepared using the method described in any of the preceding claims.

[0024] Preferably, the quantum efficiency of the water-soluble quantum sheet fluorescent probe is as high as 65% after it is transferred into water.

[0025] Preferably, water-soluble quantum sheet fluorescent probes can be used to detect the heavy metal element Ag. + Fe2+ Cu 2+ Sn 2+ In 3+ .

[0026] (III) Beneficial Effects

[0027] Compared with the prior art, the present invention provides a method for preparing and applying a water-soluble quantum sheet fluorescent probe, which has the following beneficial effects:

[0028] 1. This invention achieves the preparation of water-soluble quantum sheets by introducing ligand modification. The obtained quantum sheets can maintain fluorescence properties in the aqueous phase for up to one month. In addition, the method is simple to operate, low in cost, and has a wider range of application potential.

[0029] 2. Existing water-soluble quantum sheets generally suffer from insufficient fluorescence intensity. This invention significantly enhances the fluorescence intensity of quantum sheets by introducing specific ligands, showing a clear performance improvement compared to unmodified quantum sheets.

[0030] 3. Unlike core-shell quantum sheets, this invention does not require the construction of a complex core-shell structure. When used as a fluorescent probe, the quantum sheet allows the analyte to come into direct contact with the probe, thereby improving the response speed and sensitivity of the detection process.

[0031] 4. The water-soluble quantum sheet probe prepared by this invention can specifically recognize heavy metals such as silver and copper, causing fluorescence quenching of the quantum sheet, thereby enabling quantitative detection of them. Attached Figure Description

[0032] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0033] Figure 1 This is a flowchart of the preparation process of the present invention;

[0034] Figure 2 This is a comparison diagram showing the fluorescence quenching of quantum sheets caused by the addition of heavy metal elements to the original water-soluble quantum sheet in this invention. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] Specific implementation examples are given below.

[0037] Please see Figure 1 This invention provides a method for preparing a water-soluble quantum sheet fluorescent probe, comprising the following steps:

[0038] Step 1: Disperse the purified cadmium selenide quantum sheet in n-hexane solution, add cadmium octanoate to it, and shake in a centrifuge tube for 10 min to obtain quantum sheet with cadmium octanoate on the surface;

[0039] Step 2: Centrifuge the quantum sheet with cadmium octanoate surface at 6000 r / min for 3 min and discard the supernatant;

[0040] Step 3: Add n-hexane solution, repeat steps 1 and 2, and then place the resulting precipitate in an oven to dry at 40°C.

[0041] Step 4: Add 1 mL of 1% amphiphilic aqueous solution to the dried precipitate and sonicate for 15 min to obtain a uniformly dispersed quantum sheet aqueous solution.

[0042] In step 3, the precipitate can be dissolved and transferred by adding dichloromethane solution before drying;

[0043] In step 4, the aqueous solution of the amphiphilic substance is a sodium dodecyl sulfate solution;

[0044] The preparation method of purified cadmium selenide quantum sheets is as follows:

[0045] After dispersing cadmium selenide quantum sheets in dichloromethane solvent, cadmium octanoate is added to obtain purified cadmium selenide quantum sheets.

[0046] The preparation method of cadmium octanoate is as follows:

[0047] Cadmium octate was prepared by dissolving 0.6 mmol of cadmium oxide in 3 mL of octanoic acid at 150 degrees Celsius to obtain a clear solution.

[0048] Through the above scheme, the quantum sheet synthesized by this invention, after being transferred to water, has a quantum efficiency of up to 65%, which is about twice the fluorescence efficiency of the freshly synthesized quantum sheet. After adding ligands and transferring it to water, it can maintain its fluorescence characteristics for more than a month, and the luminescence decreases by less than 20% within a month, showing good stability.

[0049] Please see Figure 2 A water-soluble quantum sheet fluorescent probe is prepared using the above-described method for preparing a water-soluble quantum sheet fluorescent probe.

[0050] After the water-soluble quantum sheet fluorescent probe is transferred into water, the quantum efficiency reaches as high as 65%. ；

[0051] Water-soluble quantum sheet fluorescent probes can be used to detect the heavy metal element Ag. + Fe 2+ Cu 2+ Sn 2+ In 3+ .

[0052] The above solution is as follows: (Appendix) Figure 2 The sample on the left is a water-soluble quantum sheet. The sample on the right shows that adding heavy metal elements to the quantum sheet can cause fluorescence quenching, thus enabling the detection of heavy metal elements.

[0053] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A method for preparing a water-soluble quantum sheet fluorescent probe, characterized in that, Includes the following steps: Step 1: Disperse the purified cadmium selenide quantum sheet in n-hexane solution, add cadmium octanoate to it, and shake in a centrifuge tube for 10 min to obtain quantum sheet with cadmium octanoate surface. Step 2: Centrifuge the quantum sheet with cadmium octanoate surface at 6000 r / min for 3 min and discard the supernatant; Step 3: Add n-hexane solution, repeat steps 1 and 2, and then place the resulting precipitate in an oven to dry at 40°C. Step 4: Add 1 mL of 1% amphiphilic aqueous solution to the dried precipitate and sonicate for 15 min to obtain a uniformly dispersed quantum sheet aqueous solution. In step 4, the aqueous solution of the amphiphilic substance is a sodium dodecyl sulfate solution; The preparation method of purified cadmium selenide quantum sheets is as follows: After dispersing cadmium selenide quantum sheets in dichloromethane solvent, cadmium octanoate is added to obtain purified cadmium selenide quantum sheets. The preparation method of cadmium octanoate is as follows: Cadmium octanoate was prepared by dissolving 0.6 mmol of cadmium oxide in 3 mL of octanoic acid at 150 degrees Celsius to obtain a clear solution.

2. The method for preparing a water-soluble quantum sheet fluorescent probe according to claim 1, characterized in that: In step 3, the precipitate is dissolved and transferred by adding dichloromethane solution before drying.

3. A water-soluble quantum sheet fluorescent probe, characterized in that, It is prepared by the method described in any one of claims 1 to 2 for the preparation of a water-soluble quantum sheet fluorescent probe.

4. The water-soluble quantum sheet fluorescent probe according to claim 3, characterized in that: After the water-soluble quantum sheet fluorescent probe is transferred into water, the quantum efficiency reaches as high as 65%.

5. The application of a water-soluble quantum sheet fluorescent probe according to any one of claims 3 to 4, characterized in that: Used for detecting the heavy metal element Ag. + Fe 2+ Cu 2+ Sn 2+ In 3+ .

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