Gold cluster organic oxidized silica gel bundle as well as preparation method and application thereof
The preparation of gold cluster organic silica gel through self-assembly and thiol functionalization methods has solved the problem of preparing small-size gold nanoparticle CT contrast agents, and achieved particle size uniformity and structural stability. It is suitable for CT imaging and biomedical applications.
Patent Information
- Application Number
- CN202311845003.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-29
- Publication Date
- 2025-07-01
AI Technical Summary
It is difficult to synthesize small-sized gold nanoparticles in large quantities as CT contrast agents in the prior art, and there are problems such as uncontrollable size, poor structural stability and complex preparation process.
The nonionic block copolymer polyethylene oxide-block-polypropylene oxide-block-polyethylene oxide was self-assembled to form micelles, and gold cluster organic silica gels were prepared under mild conditions by adding thiol-functionalized organosilane coupling agent and chloroaulic acid reducing agent, with a controlled particle size of less than 30 nm.
The preparation of small-size gold cluster organic silica gel with uniform particle size is achieved, with good biostability and CT imaging effect, suitable for complex physiological environments, suitable for mass production and avoid particle aggregation.
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Figure CN120227480A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to nano biomedicine, and more particularly to a gold cluster organic silica micelle and its preparation method and application. Background Art
[0002] As is well known, computed tomography (CT) imaging technology is one of the important clinical disease diagnosis methods. Compared with other imaging methods, CT imaging has deep tissue penetration, higher spatial and density resolutions (Biomaterials, 2015, 42, 103 - 111; ACS Appl. Mater. Interfaces, 2015, 7, 4354–4367; Biomaterials, 2015, 38, 10 - 21). In recent years, as a promising CT contrast agent, gold nanoparticles (AuNPs) have been widely used for tumor imaging and localization (ACS NANO, 2016, 10, 2536 - 2548). Compared with iodine - based CT contrast agents used in commercial clinics, AuNPs have a higher atomic number and electron density, and exhibit higher X - ray attenuation intensity, thus significantly improving the contrast in CT imaging. Secondly, AuNPs do not show cytotoxicity within a certain concentration range and have good biocompatibility. In addition, AuNPs can be combined with targeting agents, dye molecules or specific biomarkers. Research shows that after AuNPs are combined with appropriate surface ligands, the elimination rate of nanoparticles can be slowed down through the reticuloendothelial system (RES) of the human body, and the circulation time in the blood can be prolonged (Biomaterials, 2016, 102, 87 - 97).
[0003] So far, various preparation methods of AuNPs such as the citrate reduction method have been reported in the literature. The most common ones are to assemble unstable AuNPs in uniform nanoparticles, and another method is to composite AuNPs in nanoparticles using chemical bonds such as thiol, amino or electrostatic interactions (ACS NANO, 2007, 1, 293 - 298; Chem. Mater., 2015, 17, 3398 - 3402). However, these methods have common disadvantages: (1) The size of AuNPs is uncontrollable, and large aggregates are easily formed, and the homogeneity of the obtained composite nanoparticles is poor (Chem. Mater., 2009, 21, 673 - 681); (2) The structural stability is poor, and the structure of the composite nanoparticles is easily damaged in a complex physiological environment (Langmuir, 2009, 25, 11835 - 11843); (3) The experimental process and procedures are complex. Therefore, it is still a great challenge to prepare AuNPs with excellent structural stability and size controllability in aqueous solution.
[0004] Recently, researchers reported some gold-based CT contrast agents, but there are still some problems. Such reported gold-based contrast agents often have problems of deep color and low loading due to the appearance of large-sized particles with good crystallinity (J. Mat. Chem. B., 2020, 8, 65 - 77); in addition, high doses of CT contrast agents are required to provide sufficient contrast enhancement, so there are few reports on the large-scale production of gold-based CT contrast agents at present (Adv. Funct. Mater., 2021, 31, 2007330). To our knowledge, there are few reports on the synthesis of gold-based CT contrast agents of gold nanoclusters with a size less than 2 nm. Currently, it has also been found that AuNPs of different sizes have significant effects on diagnostic utility and biological effects (i.e., blood circulation time, biodistribution, and clearance) (Sci Rep, 2019, 9, 1 - 13). Summary of the Invention
[0005] In order to solve the problems in the above-mentioned prior art, such as the lack of preparation technology for large-scale synthesis of gold-based CT contrast agents with small-sized gold particles, the present invention provides a gold cluster organosilica micelle, its preparation method and application.
[0006] According to the preparation method of the gold cluster organosilica micelle of the present invention, it includes the following steps: S1, dissolving the nonionic block copolymer poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) in water, and self-assembling to obtain an aqueous solution of polymer micelles; S2, adding ammonia water and a thiol-containing organosilane coupling agent to the aqueous solution of polymer micelles to obtain an aqueous solution of thiol / disulfide-functionalized organosilica-stabilized micelles; S3, adding chloroauric acid and a reducing agent to the aqueous solution of organosilica-stabilized micelles to form gold nanoclusters, and obtaining a gold cluster organosilica micelle.
[0007] Preferably, in step S1, poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) is a triblock copolymer as an organic template agent, and above its critical micelle concentration, it self-assembles in water to form monodisperse F127 micelles with a PPO segment as the core and a PEO segment as the shell.
[0008] Preferably, in step S2, the organosilane coupling agent undergoes hydrolysis and polycondensation within the PPO segment of the F127 micelle to form an organosilica layer, stabilizing the F127 micelle while introducing a thiol group.
[0009] Preferably, in step S3, the thiol / disulfide-doped organosilica core of the F127 hybrid micelle restricts the growth of gold clusters, and the PEO outer shell segment prevents the aggregation of gold nanoclusters.
[0010] Preferably, the organosilane coupling agent is 3-mercaptopropyltrimethoxysilane.
[0011] Preferably, the reducing agent is sodium borohydride.
[0012] Preferably, step S2 further includes removing ammonia water and unreacted organosilane coupling agent by dialysis.
[0013] Preferably, step S3 further includes removing unreacted chloroauric acid and reducing agent in the solution by dialysis.
[0014] The gold cluster organo-oxidized silica micelles obtained by the above preparation method according to the present invention have a particle size of less than 30 nm.
[0015] According to the application of the gold cluster organo-oxidized silica micelles of the present invention, the gold cluster organo-oxidized silica micelles are used as a gold-based CT contrast agent.
[0016] Preferably, the gold cluster organo-oxidized silica micelles have an enhanced CT imaging effect.
[0017] According to the preparation method of the present invention, the steps are simple, the obtained Au-FOMs have a uniform particle size, the size is less than 30 nm, no complex surface modification is required, it does not involve high temperature and strong acid or strong base environments, the reaction is mild, the operation is simple, and the same results can be obtained by repeating the experiment multiple times. Batch production can be realized. Specifically, the introduction of the organosilane coupling agent can greatly improve the structural stability and anti-dilution performance of Au-FOMs, so as to adapt to the complex in-vivo physiological environment, and at the same time avoid particle aggregation during large-scale production (at a higher concentration), realizing its application in biomedicine. Moreover, the gold cluster organo-oxidized silica micelles according to the present invention have excellent in-vivo circulation effects, can improve the CT imaging effects of the heart and liver, and have potential application prospects in the fields of targeted drug delivery, multimodal imaging, and single-atom catalysis of gold. Description of the Drawings
[0018] Figure 1 is a process flow chart for the preparation of gold cluster organo-oxidized silica micelles according to a preferred embodiment of the present invention.
[0019] Figure 2a is a statistical chart of the particle size distribution of the F127 micelles in Example 1 measured by a dynamic light scattering instrument (DLS).
[0020] Figure 2b is a statistical chart of the particle size distribution of the FOMs in Example 1 measured by DLS.
[0021] Figure 2c is measured by DLS in Example 1 10mM Statistical chart of the particle size distribution of Au-FOMs.
[0022] Figure 3 It is a statistical graph of the particle size distribution of a series of Au-FOMs of Example 2 measured by DLS.
[0023] Figure 4a It is a transmission electron microscope photograph of the FOMs of Example 2.
[0024] Figure 4b It is of Example 2 1.7mM Transmission electron microscope photograph of Au-FOMs.
[0025] Figure 4c It is of Example 2 10mM Transmission electron microscope photograph of Au-FOMs.
[0026] Figure 4d It is of Example 2 50mM Transmission electron microscope photograph of Au-FOMs.
[0027] Figure 5 It is of Example 2 10mM Energy spectrum diagram of Au-FOMs.
[0028] Figure 6 It is the XRD spectra of a series of Au-FOMs prepared with different concentrations of HAuCl4 in Example 2.
[0029] Figure 7 It is the particle size diagram of F127 micelles, FOMs, 10mM Au-FOMs of Example 2 at different dilution multiples.
[0030] Figure 8 It is of Example 2 10mM Linear relationship diagram of the CT attenuation rate of Au-FOMs and HAuCl4 varying with gold concentration in Example 2. Detailed implementation manners
[0031] The following combines the accompanying drawings to give the preferred embodiments of the present invention and describes them in detail.
[0032] As Figure 1 shown, the preparation method of the gold cluster organic silica micelles according to a preferred embodiment of the present invention first includes using the nonionic block copolymer poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (i.e., poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide), PEO 106 -b-PPO 70 -b-PEO 106, F127) was dissolved in deionized water, and an aqueous solution of polymer micelles was obtained by self-assembly. Among them, using the triblock copolymer F127 as an organic template agent, above its critical micelle concentration (CMC), monodisperse F127 micelles with a size of about 25 nm, with the PPO segment as the core and the PEO segment as the shell, can be directly formed by self-assembly in water. In a preferred embodiment, 600 mg of F127 was dissolved in 10 mL of deionized water and placed in an oven at 60 °C until it was completely dissolved to obtain monodisperse F127 micelles.
[0033] As Figure 1 shown, the preparation method of the gold cluster organosilica micelles according to a preferred embodiment of the present invention then includes adding ammonia water and a mercapto-containing organosilane coupling agent to the aqueous solution of the polymer micelles, and reacting at room temperature for 24 h to obtain an aqueous solution of mercapto-functionalized organosilica-stabilized micelles (FOMs). Among them, the mercapto-containing organosilane coupling agent undergoes hydrolysis and polycondensation within the core (PPO segment) of the F127 micelles to form an organosilica layer, stabilizing the F127 micelles while introducing mercapto groups. Preferably, the mercapto-containing organosilane coupling agent is 3-mercaptopropyltrimethoxysilane (MPTMS). Preferably, the dialysis method is used to remove ammonia water and unreacted MPTMS in the solution. In a preferred embodiment, 0.2 mL of ammonia water and 0.6 mL of MPTMS are added to the aqueous solution, and the reaction is carried out at room temperature for 24 h to obtain an aqueous solution of FOMs. The reaction solution is transferred to a dialysis bag with a molecular weight cut-off of 14,000 and dialyzed for 24 h to remove ammonia water and unreacted MPTMS in the solution.
[0034] As Figure 1As shown, the method for preparing gold cluster-organooxysilica micelles according to a preferred embodiment of the present invention then includes adding an aqueous solution of chloroauric acid (HAuCl4) and a reducing agent to an aqueous solution of organooxysilica-stabilized micelles to form gold nanoclusters, obtaining gold cluster-organooxysilica micelles (gold cluster@organooxysilica micelles, Au-FOMs). Among them, the thiol / disulfide-doped organooxysilica inner shell of the F127 hybrid micelles restricts the growth of gold clusters, and the PEO outer shell segments can prevent the aggregation of gold nanoclusters, thereby preparing Au-FOMs through a simple "in-situ confinement reduction" strategy. In particular, the Au-FOMs have excellent uniformity and dispersibility, while maintaining a high gold loading rate and a light yellow color. Preferably, the reducing agent is sodium borohydride (NaBH4). Preferably, the unreacted chloroauric acid and sodium borohydride in the solution are removed by dialysis. In a preferred embodiment, the aqueous solution of organooxysilica-stabilized micelles is diluted to 50 mL, 6 mL (solid content 24 g / mL) is taken, 12 mL of an aqueous solution of chloroauric acid with a concentration of 10 mM is added, and finally an ice aqueous solution of sodium borohydride equimolar to chloroauric acid is added. An aqueous solution of Au-FOMs is obtained by in-situ reduction. The reaction solution is transferred to a dialysis bag with a molecular weight cut-off of 14,000 and dialyzed for 24 h to remove the unreacted chloroauric acid and sodium borohydride in the solution. In a preferred embodiment, the concentration of the aqueous solution of chloroauric acid is 0 - 50 mM, the dosage is 12 mL, the molar amount of sodium borohydride is equal to that of chloroauric acid, and the dosage is 4 mL.
[0035] The gold cluster-organooxysilica micelles obtained in the present invention can be used as a contrast agent for computed tomography (CT), and have good biostability, biosafety, anti-dilution property, and excellent computed tomography (CT) imaging ability. Specifically, the gold cluster-organooxysilica micelles can be used for CT imaging diagnosis, and the imaging performance comes from the fact that gold particles exhibit a higher X-ray attenuation intensity, thereby significantly improving the contrast in CT imaging.
[0036] Example 1
[0037] Dissolve 600 mg of F127 in 10 mL of deionized water, place it in an oven at 60 °C, and after complete dissolution, add 0.2 mL of NH 3· H2O and 0.6 mL of MPTMS, and stir at room temperature for 24 h. Transfer the reacted solution to a dialysis bag with a molecular weight cut-off of 14,000, and change the dialysis water every 4 h. Dialyze for 24 h to obtain an FOMs solution. Dilute the obtained FOMs solution to 50 mL, take 6 mL, add 12 mL of an aqueous solution of HAuCl4 with a concentration of 10 mM, stir for 5 min, and then add 4 mL of NaBH4 equimolar to HAuCl4. Stir at room temperature for 24 h. Dialyze the obtained product for 24 h to obtain 10mM Au-FOMs.
[0038] As Figure 2a shown, the average particle size of F127 micelles is 22.3 nm. As Figure 2b shown, the average particle size of FOMs is 28.5 nm. As Figure 2c shown, 10mM the average particle size of Au-FOMs is 26.6 nm. Obviously, there is no significant difference in particle size at each stage of the preparation process.
[0039] Example 2
[0040] The specific steps are the same as those in Example 1, only changing the concentration of HAuCl4 (1.7, 10, 13, 17.5, 25, 50 mM) and the corresponding concentration of NaBH4, and finally a series of Au-FOMs are obtained.
[0041] As Figure 3 shown, with the increase in the amount of HAuCl4 used, the particle size of the gold cluster organosilica micelles obtained in the present invention also increases to a certain extent.
[0042] As Figure 4a shown, no gold nanoclusters can be seen on FOMs. As Figure 4b shown, 1.7mM no gold nanoclusters can be seen on Au-FOMs. As Figure 4c shown, each 10mM Au-FOMs has 3 - 4 gold nanoclusters, with a size of about 1.5 nm. As Figure 4d shown, each 50mM Au-FOMs is loaded with 5 - 6 gold nanoclusters, with a size of about 2.1 nm.
[0043] Figure 5 of 10mM The energy spectrum of Au-FOMs shows the presence of gold element.
[0044] As Figure 6 shown, when the concentration of HAuCl4 is higher than 13 mM, large particle gold nanoparticles will appear in the material.
[0045] As Figure 7 shown, 10mM Au-FOMs can still maintain a stable structure at different dilution multiples.
[0046] As Figure 8 shown, 10mM Au-FOMs can significantly improve the CT imaging effect.
[0047] The above are only the preferred embodiments of the present invention, and are not intended to limit the scope of the present invention. Various changes can be made to the above embodiments of the present invention. That is, all simple, equivalent changes and modifications made in accordance with the claims and the content of the specification of the present invention application shall fall within the scope of protection of the claims of the present invention patent. Those not described in detail in the present invention are all conventional technical contents.
Claims
1. A method for preparing a gold cluster organic silica micelle, characterized in that, The preparation method comprises the following steps: S1. Dissolve the nonionic block copolymer poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) in water, and self-assemble to obtain an aqueous solution of polymer micelles; S2. Add ammonia water and an organosilane coupling agent containing a mercapto group to the aqueous solution of polymer micelles to obtain an aqueous solution of mercapto / disulfide-functionalized organosilica-stabilized micelles; S3. Add chloroauric acid and a reducing agent to the aqueous solution of organosilica-stabilized micelles to form gold nanoclusters, and obtain gold cluster organosilica micelles.
2. The preparation method according to claim 1, characterized in that, In step S1, poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) is a triblock copolymer serving as an organic template agent, and above its critical micelle concentration, it self-assembles in water to form monodisperse F127 micelles with a PPO segment as the core and a PEO segment as the shell.
3. The preparation method according to claim 2, characterized in that, In step S2, the organosilane coupling agent undergoes hydrolysis and polycondensation within the PPO segment of the F127 micelles to form an organosilica layer, stabilizing the F127 micelles and introducing mercapto groups at the same time.
4. The preparation method according to claim 2, characterized in that, In step S3, the mercapto / disulfide-doped organosilica inner core of the F127 hybrid micelles restricts the growth of gold clusters, and the PEO outer shell segments prevent the aggregation of gold nanoclusters.
5. The preparation method according to claim 1, characterized in that, The organosilane coupling agent is 3-mercaptopropyltrimethoxysilane.
6. The preparation method according to claim 1, characterized in that, The reducing agent is sodium borohydride.
7. The preparation method according to claim 1, characterized in that, Step S2 further includes removing ammonia water and unreacted organosilane coupling agent by dialysis.
8. The preparation method according to claim 1, characterized in that, Step S3 further includes removing unreacted chloroauric acid and the reducing agent in the solution by dialysis.
9. A gold cluster organic silica micelle obtained by the preparation method according to any one of claims 1-8, characterized in that, The particle size of the gold cluster organosilica micelles is less than 30 nm.
10. The application of the gold cluster organic oxidized silica micelle according to claim 9, wherein, The gold cluster organosilica micelles are used as a gold-based CT contrast agent.