Preparation method and application of water-soluble quantum chip fluorescent probe

Abstract

The invention belongs to the technical field of fluorescent probe preparation, and particularly relates to a preparation method and application of a water-soluble quantum chip fluorescent probe, and the preparation method comprises the following steps: step 1, dispersing a purified cadmium selenide quantum chip in an n-hexane solution, adding cadmium caprylate into the n-hexane solution, and oscillating in a centrifugal tube for 10 minutes to obtain a quantum chip with cadmium caprylate on the surface; step 2, centrifuging the quantum chip with cadmium caprylate on the surface at the speed of 6000 r / min for 3 minutes, and discarding supernate; step 3, adding an n-hexane solution, repeating the operations of the step 1 and the step 2, and drying the obtained precipitate in a drying oven at 40 DEG C; step 4, adding 1 mL of a 1% amphiphilic substance aqueous solution into the dried precipitate, and carrying out ultrasonic treatment for 15 minutes to obtain a uniformly dispersed quantum chip aqueous solution; the water-soluble quantum chip is water-soluble, can be directly synthesized in water and is more beneficial to practical application, and meanwhile, the water-soluble quantum chip added with the ligand can keep the fluorescence characteristic of about one month.

Description

Technical Field

[0001] The invention belongs to the technical field of fluorescent probe preparation, and specifically relates to a preparation method and application of a water-soluble quantum sheet fluorescent probe. Background Art

[0002] Water-soluble probes refer to probe molecules that can dissolve and maintain stability in water. They usually have a specific chemical structure and can interact specifically with biomolecules or other targets, thereby providing important information about the targets. Based on their structural and application differences, water-soluble probes can be divided into fluorescent probes, chemiluminescent probes, nuclear magnetic resonance probes and other types.

[0003] Semiconductor nanocrystals are considered to be ideal fluorescent emission materials in terms of spectral characteristics 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 by colloidal methods, so that each particle presents an integer atomic layer structure in thickness and an extended state in two dimensions. This makes the quantum sheet experience the same level of quantum confinement in the thickness direction, and the spectral characteristics of a single particle and the collection are highly consistent. In addition, quantum sheets exhibit superior properties such as high fluorescence quantum yield, large single-photon and two-photon absorption cross sections, making them show a wide range of application prospects in multiple fluorescent labeling biological systems. However, most cadmium sulfide quantum sheets are synthesized in organic solvents, while biological research environments usually require water-soluble materials. Although a large number of studies have been devoted to improving fluorescence quantum yields and achieving aqueous phase transfer, there are additional technical challenges in the phase transfer process due to the specific geometry of quantum sheets. For example, ligand exchange is the most commonly used transfer strategy, but simple ligand exchange can easily damage the surface of the quantum sheet, resulting in fluorescence quenching. In addition, the exposed surface is susceptible to chemical attack, further reducing the fluorescence brightness.

[0004] In early studies on the transfer of quantum chips into aqueous phases, Lim et al. proposed a combination of phospholipids, detergents, and membrane scaffold proteins to effectively wrap quantum chips to adapt to their geometric properties. To maintain fluorescence properties, they grew a cadmium selenide shell (CdSe shell) outside the core of a cadmium selenide (CdSe) quantum chip. Although this method achieved a quantum yield of 4.3% in hexane, the quantum yield in the aqueous phase dropped to 1.6%. This protein encapsulation strategy gives quantum chips biological properties such as rapid cellular uptake, but its reliance on expensive protein materials limits the scalability of large-scale applications. Kechkeche et al. proposed a two-step ligand exchange method, first using small molecule ligands to transfer quantum chips to the aqueous phase, and then forming the final coating by introducing a specially made water-soluble polymer. The advantage of this strategy is the ability to customize the polymer, which can introduce a variety of functional groups and improve the dispersibility of quantum chips in high ionic strength water environments. However, the limitation of this method is that it relies on complex polymer design and a two-step operation process, which increases the complexity of the experiment. To simplify the encapsulation and aqueous phase transfer of quantum chips, 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 the hydrophobic ligands on the surface of the quantum chips through hydrophobic interactions, while the anhydride units hydrolyze in the aqueous phase to generate a large number of negatively charged carboxylic acid groups, which significantly improve the aqueous phase stability of the quantum chips. This strategy has attracted attention due to its simple operation, cheap and readily available starting materials, and good scalability. However, the synthesis process of the polymer in this method is still relatively complicated and needs to be further optimized to meet the needs of practical applications.

[0005] However, there are still some problems in the practical application of the above technologies:

[0006] 1. Lim et al. used a combination of phospholipids, detergents, and membrane scaffold proteins that matched the geometry of the quantum sheets in order to wrap them around the quantum sheets and then transfer the quantum sheets to water; however, this encapsulation technology relies on expensive protein synthesis, limiting the scalability of this approach;

[0007] 2. Kechkeche et al. used a two-step ligand exchange method, first using simple small molecule ligands to transfer the quantum sheets to the aqueous phase, and then connecting a specially prepared water-soluble polymer as a final coating to disperse the quantum sheets in a high ionic strength water environment; however, this method is complex to operate, costly, and has low fluorescence efficiency and poor stability.

[0008] Therefore, in order to solve the above problems, a preparation method and application of a water-soluble quantum sheet fluorescent probe are proposed. Summary of the invention

[0009] 1. Technical issues to be resolved

[0010] In view of the deficiencies in the prior art, the present invention provides a method for preparing a water-soluble quantum sheet fluorescent probe and its application, so as to solve the problems raised in the specification.

[0011] (II) Technical solution

[0012] To achieve the above object, 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, dispersing the purified cadmium selenide quantum flakes in a n-hexane solution, adding cadmium octanoate thereto, and shaking in a centrifuge tube for 10 minutes to obtain a quantum flake with cadmium octanoate on the surface;

[0014] Step 2, the quantum chip with cadmium octanoate on the surface is centrifuged at 6000r / min for 3min, and the supernatant is discarded;

[0015] Step 3, adding n-hexane solution, repeating steps 1 and 2, and then placing the obtained precipitate in an oven and drying it at 40°C;

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

[0017] Preferably, in step 3, a dichloromethane solution may be added to the precipitate for dissolution and transfer before drying.

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

[0019] Preferably, the preparation method of purified cadmium selenide quantum sheets is:

[0020] After dispersing the cadmium selenide quantum flakes in a dichloromethane solvent, cadmium octanoate is added thereto to obtain purified cadmium selenide quantum flakes;

[0021] The preparation method of cadmium octanoate is:

[0022] 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.

[0023] A water-soluble quantum sheet fluorescent probe is prepared by the preparation method of a water-soluble quantum sheet fluorescent probe as described in any one of the above items.

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

[0025] Preferably, the water-soluble quantum sheet fluorescent probe 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 preparation method and application of a water-soluble quantum sheet fluorescent probe, which has the following beneficial effects:

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

[0029] 2. Existing water-soluble quantum chips generally have the problem of insufficient fluorescence intensity. The present invention significantly enhances the fluorescence intensity of the quantum chips by introducing specific ligands, showing obvious performance improvement compared with unmodified quantum chips.

[0030] 3. The present invention is different from the core-shell structure quantum chip. The present invention does not need to construct a complex core-shell structure. When used as a fluorescent probe, the quantum chip allows the detected object to directly contact the probe, thereby improving the response speed and sensitivity of the detection process.

[0031] 4. The water-soluble quantum sheet probe prepared by the present invention can specifically identify heavy metals such as silver and copper, causing the fluorescence quenching of the quantum sheet, thereby performing quantitative detection thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0033] Figure 1 It is a preparation flow chart of the present invention;

[0034] Figure 2 It is a comparison diagram of the original water-soluble quantum tablet in the present invention and the quantum tablet fluorescence quenching caused by adding heavy metal elements into the quantum tablet. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. 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.

[0036] Specific examples are given below.

[0037] See also Figure 1 The present invention provides a method for preparing a water-soluble quantum sheet fluorescent probe, comprising the following steps:

[0038] Step 1, dispersing the purified cadmium selenide quantum flakes in a n-hexane solution, adding cadmium octanoate thereto, and shaking in a centrifuge tube for 10 minutes to obtain a quantum flake with cadmium octanoate on the surface;

[0039] Step 2, the quantum chip with cadmium octanoate on the surface is centrifuged at 6000r / min for 3min, and the supernatant is discarded;

[0040] Step 3, adding n-hexane solution, repeating steps 1 and 2, and then placing the obtained precipitate in an oven and drying it at 40°C;

[0041] Step 4: Add 1 mL of 1% aqueous solution of amphiphilic substance to the dried precipitate and perform ultrasonication for 15 min to obtain a uniformly dispersed aqueous solution of quantum chips;

[0042] In step 3, a dichloromethane solution may be added to the precipitate for dissolution and transfer 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 chips is as follows:

[0045] After dispersing the cadmium selenide quantum flakes in a dichloromethane solvent, cadmium octanoate is added thereto to obtain purified cadmium selenide quantum flakes;

[0046] The preparation method of cadmium octanoate is:

[0047] 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.

[0048] Through the above scheme: after the quantum sheet synthesized by the present invention is transferred into water, the quantum efficiency is as high as 65%, which is about twice the fluorescence efficiency of the freshly synthesized quantum sheet. After adding the ligand and transferring it into water, the fluorescence characteristics can be maintained for more than one month, and the luminescence decreases by less than 20% within one month, which has relatively good stability.

[0049] See also Figure 2 , a water-soluble quantum sheet fluorescent probe, prepared by the above-mentioned method for preparing a water-soluble quantum sheet fluorescent probe;

[0050] The water-soluble quantum sheet fluorescent probe has a quantum efficiency of up to 65% after being transferred into water ；

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

[0052] Through the above scheme: Figure 2 The sample on the left is a water-soluble quantum chip, and the right shows that adding heavy metal elements to the quantum chip can cause fluorescence quenching of the quantum chip, thereby realizing the detection of heavy metal elements.

[0053] The above shows and describes 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, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A method for preparing a water-soluble quantum sheet fluorescent probe, characterized in that: The following steps are involved: Step 1, dispersing the purified cadmium selenide quantum flakes in a n-hexane solution, adding cadmium octanoate thereto, and shaking in a centrifuge tube for 10 minutes to obtain quantum flakes with cadmium octanoate on the surface; Step 2, the quantum chip with cadmium octanoate on the surface is centrifuged at 6000r / min for 3min, and the supernatant is discarded; Step 3, adding n-hexane solution, repeating steps 1 and 2, and then placing the obtained precipitate in an oven and drying it at 40°C; Step 4: Add 1 mL of 1% aqueous solution of amphiphilic substance to the dried precipitate and ultrasonicate for 15 min to obtain a uniformly dispersed aqueous solution of quantum chips.

2. The method for preparing a water-soluble quantum sheet fluorescent probe according to claim 1, characterized in that: In step 3, a dichloromethane solution may be added to the precipitate for dissolution and transfer before drying.

3. The method for preparing a water-soluble quantum sheet fluorescent probe according to claim 1, characterized in that: In step 4, the aqueous solution of the amphiphilic substance is a sodium dodecyl sulfate solution.

4. The method for preparing a water-soluble quantum sheet fluorescent probe according to claim 1, characterized in that: The preparation method of purified cadmium selenide quantum chips is as follows: After dispersing the cadmium selenide quantum flakes in a dichloromethane solvent, cadmium octanoate is added thereto to obtain purified cadmium selenide quantum flakes; The preparation method of cadmium octanoate is: 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.

5. A water-soluble quantum sheet fluorescent probe, characterized in that: The water-soluble quantum sheet fluorescent probe is prepared by the preparation method of any one of claims 1 to 4.

6. A water-soluble quantum sheet fluorescent probe according to claim 5, characterized in that: The water-soluble quantum sheet fluorescent probe has a quantum efficiency of up to 65% after being transferred into water 。 7. The use of a water-soluble quantum sheet fluorescent probe according to any one of claims 5 to 6, characterized in that: Used to detect heavy metal element Ag + , Fe 2+ , Cu 2+ , Sn 2+ ,In 3+ .

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