Novel micelle-like structure nanoparticles and preparation method thereof
By introducing BTEAB into surfactant micelles for covalent cross-linking, micellar-like structure nanoparticles are formed, which solves the problems of poor micellar stability and difficulty in functional release, and realizes stable loading of guest molecules at physiological pH and passes The pH and oxidant response achieve functional release effects.
Patent Information
- Application Number
- CN202411506944.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-28
- Publication Date
- 2025-02-11
AI Technical Summary
The existing surfactant micelle carriers have poor stability in complex fluids, are prone to dissociation, lead to leakage of guest molecules, and are difficult to achieve functional release.
Covalent crosslinking is performed by introducing bisbenzyl boric acid BTEAB connected with ethyl spacer groups into a mixed micelle of anionic surfactant SDS and dextran hydrophobic modified amphiphilic molecules D10-C18 to form a micelle-like structure Nanoparticles, achieving stable micellar structure and functional release.
The prepared micelle-like nanoparticles have a single-core structure that can load guest molecules of different properties at physiological pH, and achieve functional sustained or rapid release through pH and oxidant response, improving the stability and functionality of the carrier.
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Figure CN119405837A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of nano-functional carriers, and specifically relates to the micelle-like structural characteristics, pH and oxidant environmental stimulation response functions of nanoparticles and a preparation method thereof. Background Art
[0002] Surfactant micelles have discontinuous microregions at the interface between the polar shell and the hydrophobic core. As carriers of guest molecules, their basic characteristic is the solubilization of hydrophobic guests. This ability is the basis for the widespread application of surfactants, while the small radial thickness of the polar shell contributes little to the loading of guest molecules. The key problem faced by this aggregate carrier is the stability of the micelles. On the one hand, the dynamic equilibrium between micelles and monomers makes it possible for the guest to be exposed to the environment. On the other hand, any component that can interact weakly with surfactant monomers or micelles in complex fluids may cause the dissociation of micelles and cause leakage of guest molecules. The micelles formed by amphiphilic molecules with hydrophilic polymers as hydrophilic groups have a relatively large and adjustable effective polar region volume. The main difference from surfactant micelles is that they are easy to form multi-hydrophobic core micelles with larger micelle volume and better stability, but they face challenges such as aggregation caused by interactions between micelles, guest molecule loading and functional release. Summary of the invention
[0003] The technical problem solved by the present invention is to provide a micellar structure nanoparticle and a preparation method thereof. On the basis of mixed micelles of anionic surfactant (SDS) and hydrophobically modified amphiphilic molecules of dextran (D10-C18), dibenzylammonium boric acid (BTEAB) connected by ethyl spacer groups is covalently cross-linked, which can effectively avoid the generation of multi-core micelles of D10-C18, the cross-linking of adjacent micelles by BTEAB, and the phenomenon of non-localized polymorphic cross-linking in the dextran layer, and finally obtain a new type of micellar structure nanoparticle with uniform structure. The micellar structure nanoparticle prepared by the method has a single-core micelle structure but no dynamic equilibrium between micelles and monomers; it has a non-ionic layer with a large radial size and a tightly arranged multi-layer ionic layer polar shell, and combined with the solubilization function of the hydrophobic core, it can load guest molecules of different properties at the same time; the boric acid diol ester generated in situ by diphenylboronic acid linker molecules has the functionality of pH and oxidation response guest molecule slow release or rapid release, and can be used as a nano functional carrier to load guest molecules.
[0004] The mechanism of preparing micelle-like structure nanoparticles of the present invention is as follows: BTEAB is adsorbed onto the surface of SDS micelles through electrostatic action to form a dense charge layer of micelles with a net negative charge, and at the same time, the boric acid hydroxyl group reacts with the hydroxyl group of D10-C18 to generate a covalently linked borate ester, thereby realizing the preparation of micelle-like structure nanoparticles in which self-assembly and in-situ synthesis of borate ester bonds promote each other. The micelle-like structure nanoparticles can load hydrophilic guest molecules in the polar region and hydrophobic guest molecules in the hydrophobic core through electrostatic, hydrogen bond and / or π-π action at physiological pH, and any factors that can weaken the covalent bond, weakly interact or destroy the molecular structure of BTEAB may convert the micelle-like structure nanoparticles into mixed micelles or even destroy the mixed micelle structure, thereby giving the micelle-like structure nanoparticles a carrier performance of functional loading and rapid or slow release of guest molecules.
[0005] The present invention adopts the following technical scheme to solve the above technical problems. The novel micelle-like structure nanoparticles are characterized in that: a mixed micelle of anionic surfactant SDS and dextran hydrophobically modified amphiphilic molecule D10-C18 is used as a template, and D10-C18 is covalently cross-linked by dibenzylammonium borate BTEAB connected by an ethyl spacer group to obtain micelle-like structure nanoparticles. The micelle-like structure nanoparticles have a spherical geometric shape, and three discontinuous micro-regions are arranged in sequence from the outside to the inside along the radial direction, namely, a loose polysaccharide chain non-ionic polyhydroxy layer, an ionic layer with negative-positive-negative charges closely arranged, and a hydrophobic core. The structure and molecular structure of the micelle-like structure nanoparticles are respectively:
[0006] The average value of n is 50.
[0007] The preparation method of the novel micelle-like structure nanoparticles of the present invention is characterized by the specific steps of: in a weakly alkaline PBS buffer solution, using anionic surfactant SDS micelles as templates, adding dibenzyl ammonium borate BTEAB with a charge ratio equal to that of SDS to form spherical binary mixed micelles, wherein part of BTEAB is electrostatically adsorbed on the surface of the SDS micelles as counterions, and continuously adding dextran hydrophobically modified amphiphilic molecules D10-C18 under stirring conditions, so that the BTEAB electrostatically adsorbed on the surface of the SDS micelles is positioned at the charge layer position of the ternary mixed micelles formed with D10-C18, promoting the in-situ esterification reaction between the boric acid group of BTEAB and the alcoholic hydroxyl group of D10-C18, and covalently cross-linking the amphiphilic molecules constituting the mixed micelles to form micelle-like structure nanoparticles.
[0008] It is further defined that the pH of the spherical binary mixed micelles is 9.5-10.5; the prepared micelle-like structured nanoparticles can be used within the physiological pH range, the cmc of SDS in 20 mM PBS measured by fluorescent probe method, the acid dissociation constant of BTEAB in SDS micelles measured by UV spectroscopy, and the SDS-BTEAB-pH phase diagram all support that under weakly alkaline conditions, BTEAB can be electrostatically adsorbed on the surface of SDS micelles without affecting the structure of the micelles.
[0009] It is further defined that the concentration of BTEAB in the spherical binary mixed micelle system is lower than 1 / 2 of the concentration of SDS, and excessive BTEAB may cause cross-linking between the nanoparticles of the final product and precipitation, wherein the concentration of SDS is lower than 25 mM, and spherical binary mixed micelles can be obtained.
[0010] It is further defined that the molar ratio of D10-C18 to SDS is 0.5:1 to 1:1, and an excess of D10-C18 is not conducive to forming a closed covalent cross-linked network.
[0011] The micelle-like structured nanoparticles of the present invention are used as nano-functional carriers. The micelle-like structured nanoparticles can load hydrophilic guest molecules in the polar region and hydrophobic guest molecules in the hydrophobic core through electrostatic, hydrogen bonding and / or π-π interaction under physiological pH conditions. The micelle-like structured nanoparticles loaded with guest molecules under weak alkaline conditions have a weak interaction-covalent bond positively correlated stable structure. Under weak acidic conditions, the micelle-like structured nanoparticles are converted into mixed micelles and further lose the mixed micelle structure, thereby achieving the functional release of guest molecules regulated by pH. In the presence of an oxidant, the micelle-like structured nanoparticles can oxidatively decompose and destroy the covalent bond between the aromatic group and the boron atom, thereby achieving the functional release of guest molecules regulated by the oxidant.
[0012] It is further defined that the guest molecules are hydrophobic dye molecules and water-soluble catechol molecules, and the oxidant is H2O2.
[0013] Compared with the nanoparticles that have been reported, the micelle-like structured nanoparticles prepared by the present invention have the following comprehensive structural characteristics: (1) The micelle-like structured nanoparticles retain the surface characteristics of the SDS / D10-C18 mixed micelles, and the polar region is composed of a loosely stacked polysaccharide chain layer (about 50 glucose units) and a tightly arranged negative-positive-negative charge layer, which can load polar guest molecules that interact with the polar layer groups through electrostatic, hydrogen bonding and π-π interactions in the polar region; (2) The hydrophobic core of the micelle-like structured nanoparticles composed of alkyl chains is a sol-like microphase region, which can load a The hydrophobic guest molecules of a certain size are loaded in the hydrophobic core region; (3) BTEAB and D10-C18 are in situ covalently cross-linked near the charge layer, and can form stable micelle-like structured nanoparticles at weakly alkaline pH. The tight charge layer can effectively limit the leakage of the guest molecules loaded in the hydrophobic core; (4) Under weakly acidic conditions, the boronate bonds in the micelle-like structured nanoparticles are broken, and the micelle-like structured nanoparticles are reversibly converted into mixed micelles. The dynamic equilibrium between the mixed micelles and the monomers of each component puts the guest molecules in a kinetic process of slow release or rapid release that depends on the environment.
[0014] Compared with the prior art, the present invention has the following advantages and beneficial effects: the micelle-like structure nanoparticles prepared by the present invention are spherical structures, and three discontinuous micro-regions are arranged in sequence from the outside to the inside along the radial direction, namely, a loose polysaccharide chain non-ionic polyhydroxy layer, an ionic layer with negative-positive-negative charges tightly arranged, and a hydrophobic core. This structure determines that it can be used as a nano-sized carrier of guest molecules of different properties; under weakly alkaline conditions, the micelle-like structure nanoparticles are a weak interaction-covalent bond positively correlated stable structure, and under weakly acidic conditions, the micelle-like structure nanoparticles are converted from nanoparticles to mixed micelles and further lose the mixed micelle structure, thereby realizing the functional release of guest molecules regulated by pH; in the presence of an oxidant, such as millimolar concentration of H2O2, the covalent bond between the aromatic group and the boron atom can be oxidatively decomposed to destroy the micelle-like structure nanoparticles, thereby realizing the functional release of guest molecules regulated by the oxidant. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1 The cmc of SDS was measured by the curve method of the intensity ratio of the pyrene fluorescence I1 and I3 bands versus SDS concentration. The solvent was a 20 mM PBS buffer solution with a pH of 7.0, the pyrene concentration was 0.02 mM, and the excitation wavelength was 335 nm.
[0016] Figure 2 The measured values of BTEAB absorbance at 266 nm, Boltzmann simulation and its first-order derivative curves as a function of pH. The solvent was 20 mM PBS buffer solution, and the concentrations of BTEAB and SDS were 0.8 mM and 50 mM, respectively.
[0017] Figure 3 This is the SDS-BTEAB-pH isotherm phase diagram of BTEAB / SDS binary mixed micelle solution.
[0018] Figure 4 The intrinsic fluorescence intensity of BTEAB in the SDS / D10-C18 / BTEAB ternary mixed micelle solution changes with pH. The concentrations of SDS, D10-C18, BTEAB and PBS are 25.0mM, 2.0mM, 0.8mM and 20mM, respectively. The excitation wavelength is λ ex =266nm.
[0019] Figure 5 12.5 mM BTEAB in 20 mM PBS buffer at pH 9.5 11 B NMR, (a) pure BTEAB; (b) BTEAB / SDS (SDS: 25 mM) binary mixed micelle solution; (c–f) BTEAB / SDS / D10-C8 (SDS: 25 mM) ternary mixed micelle solution, in which the concentrations of D10-C18 are (c) 12.5 mM, (d) 15.0 mM, (e) 20 mM and (f) 25 mM, respectively. DETAILED DESCRIPTION
[0020] The above contents of the present invention are further described in detail below through examples, but this should not be understood as the scope of the above subject matter of the present invention being limited to the following examples, and all technologies implemented based on the above contents of the present invention belong to the scope of the present invention. Example
[0021] A binary mixed micelle solution of SDS and BTEAB was prepared in a PBS buffer solution at pH = 9.5. When the concentration of SDS was 25 mM, a spherical binary mixed micelle solution with a negative surface charge was obtained, in which the concentration of BTEAB was 12.5 mM. As the counterion of SDS, part of BTEAB was electrostatically adsorbed on the surface of the SDS micelle through two quaternary ammonium salt positive charges. Therefore, there was a dynamic balance between free ions and electrostatically adsorbed ions of BTEAB in the solution. There were also free SDS monomers in the solution, and the concentration was the critical micelle concentration (cmc) under the implementation conditions, which was approximately equal to the measured value of the same concentration in PBS at neutral pH, which was 2.60 mM, as shown in Figure 2. Figure 1 shown.
[0022] BTEAB is electrostatically adsorbed to the surface of SDS micelles to form salt. The apparent pH of BTEAB can be measured by measuring the change of the absorbance of BTEAB at the maximum absorption wavelength with pH. K a . Apparent p K aIt reflects the comprehensive result of monomer and electrostatic adsorption BTEAB acid dissociation, which is related to the fraction of BTEAB adsorption. Under the condition of sufficient excess of SDS, such as when the concentrations of BTEAB and SDS are 0.8mM and 50mM, respectively, the p K a The measured value is 9.42, such as Figure 2 Therefore, when the pH is greater than 9.42, the salt generated by the electrostatic neutralization of the positive charge of the quaternary ammonium salt of BTEAB and the negative charge of SDS has a net negative charge derived from the borate group of BTEAB, and is a micellar solution with a negative charge on the surface in the buffer solution. When the pH is less than 9.42, the boric acid of the BTEAB molecule mainly exists in a non-ionic acid structure, and BTEAB and SDS are electrostatically neutralized to form a neutral insoluble salt, as shown in Figure 3 As shown in the phase diagram, the binary mixed micelle solution of BTEAB and SDS prepared at pH=9.5 or above can obtain a stable micelle solution at any molar fraction. In order to obtain spherical binary mixed micelles, the concentration of SDS needs to be controlled below 25 mM.
[0023] The D10-C18 glucan chain is rich in hydroxyl groups. When the ternary mixed micelle solution is gradually formed by titrating D10-C18, BTEAB adsorbed on the negatively charged site of SDS forms a boric acid ester with the hydroxyl group of the first or second sugar unit connected to the D10-C18 alkyl chain. The experimental results show that due to the lack of cis-vicinal dihydroxyl groups on D10-C18, it cannot form a five-membered ring diol ester with aromatic boronic acid. However, in the ternary mixed micelle system designed by the present invention, BTEAB, whose thermal motion is restricted, has the possibility of forming two monoester bonds with adjacent D10-C18. The apparent p of BTEAB K a Measurements can indirectly indicate the presence of borate esters, such as Figure 4 As shown, the p values were calculated when the concentrations of BTEAB, SDS and D10-C18 were 0.8 mM, 25 mM and 2.0 mM, respectively. K a The measured value is 7.69, which is less than the p value without D10-C18. K a 9.42, illustrating the formation of an in situ boronate ester bond. 11 B NMR can directly characterize borate esters qualitatively and even quantitatively from chemical shift changes. Figure 5 The results of BTEAB, BTEAB / SDS binary mixed micelle solutions and BTEAB / SDS / D10-C18 ternary mixed micelles with different concentrations of D10-C18 are given. 11 B NMR spectrum, at pH = 9.5, pure BTEAB is basically sp 3hybrid state, the chemical shift is 3.18. After adding SDS with 2 times the molar concentration of BTEAB, due to the p K a From 7.17 of pure BTEAB to 9.42, sp 2 The hybridization score increases. 11 The B NMR signal peak moves downfield to a chemical shift of 5.74. When D10-C18 is added in an amount equal to that of BTEAB, four signals of a restricted state of thermal motion are displayed. The peaks with chemical shifts of 5.35 and 6.32 are the signals of the esterified and unesterified boronic acid groups of BTEAB that interact electrostatically with SDS. The boron atom of the esterified boronic acid group is sp 3 Hybridization, signal shifted upfield, no esterified boronic acid group sp 2 The hybrid components are relatively increased, so they move to the downfield. The signals at chemical shifts of 2.58 and 1.35 are associated with BTEAB far away from the negative charge of SDS. The former is the signal of the corresponding ester, and the latter is the signal of the non-esterified sp 3 The signal of the hybridized boron atom. From the relative integrated area of each signal peak, it can be seen that the peak with a displacement of 5.35 has the largest integrated area, indicating that BTEAB mainly exists in the form of both electrostatic interaction with SDS and ester bond formation with D10-C18 hydroxyl groups. Based on this, it can be seen that the BTEAB / SDS / D10-C18 ternary mixed micelles in situ form micelle-like structured nanoparticles with a positive synergistic effect of weak electrostatic interaction and covalent cross-linking. Combining the known pH response function of the borate ester bond and the oxidation response function of the boric acid-benzene ring covalent bond (such as H2O2 response), the micelle-like structured nanoparticles prepared by the present invention can be used as nano-functional carriers, and can load hydrophilic guest molecules in the polar region through electrostatic, hydrogen bonding and / or π-π interactions at physiological pH, and load hydrophobic guest molecules in the hydrophobic core through hydrophobic interactions. Any factors that can weaken the covalent bonds, weak interactions or destroy the BTEAB molecular structure may convert the nanoparticles into mixed micelles or even destroy the micelle structure, thus giving the synthesized micelle-like structured nanoparticles the carrier properties of functional loading and rapid or slow release of guest molecules.
[0024] The above embodiments describe 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 above embodiments and descriptions are only for illustrating the principles of the present invention. Without departing from the principles of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of protection of the present invention.
Claims
1. New micelle-like nanoparticles, characterized by: Using the mixed micelle of anionic surfactant SDS and dextran hydrophobically modified amphiphilic molecule D10-C18 as a template, D10-C18 is covalently cross-linked by dibenzylammonium borate BTEAB connected by an ethyl spacer group to obtain micelle-like structured nanoparticles. The micelle-like structured nanoparticles have a spherical geometric structure, and three discontinuous micro-regions are arranged in sequence from the outside to the inside along the radial direction, namely, a loose polysaccharide chain non-ionic polyhydroxy layer, an ionic layer with negative-positive-negative charges tightly arranged, and a hydrophobic core. The structure and molecular structure of the micelle-like structured nanoparticles are as follows: The average value of n is 50.
2. A method for preparing the novel micelle-like structure nanoparticles according to claim 1, characterized in that The specific steps are as follows: in a weakly alkaline PBS buffer solution, anionic surfactant SDS micelles are used as templates, and dibenzyl ammonium borate BTEAB with a charge ratio equal to that of SDS is added to form spherical binary mixed micelles, wherein part of the BTEAB is electrostatically adsorbed on the surface of the SDS micelles as a counterion, and dextran hydrophobically modified amphiphilic molecules D10-C18 are continuously added under stirring conditions, so that the BTEAB electrostatically adsorbed on the surface of the SDS micelles is positioned at the charge layer position of the ternary mixed micelles formed with D10-C18, and the boronic acid group of BTEAB is promoted to react with the alcoholic hydroxyl group of D10-C18 in situ to covalently cross-link the amphiphilic molecules constituting the mixed micelles into micelle-like structured nanoparticles.
3. The method for preparing the novel micelle-like structure nanoparticles according to claim 2, characterized in that: The spherical binary mixed micelles are prepared under the condition of pH=9.5-10.5, and the prepared micelle-like structured nanoparticles can be used near the physiological pH range.
4. The method for preparing novel micelle-like nanoparticles according to claim 2, characterized in that: The concentration of BTEAB in the spherical binary mixed micelles is lower than 1 / 2 of the concentration of SDS, wherein the concentration of SDS is lower than 25 mM, so as to obtain the spherical binary mixed micelles.
5. The method for preparing novel micelle-like nanoparticles according to claim 2, characterized in that: The molar ratio of D10-C18 to SDS is in the range of 0.5:1 to 1:
1.
6. The novel micelle-like structured nanoparticles according to claim 1 can be used as nano-functional carriers of guest molecules.
7. The use according to claim 6, characterized in that: The micelle-like structured nanoparticles can load hydrophilic guest molecules in the polar region through electrostatic, hydrogen bonding and / or π-π interactions under physiological pH conditions, and load hydrophobic guest molecules in the hydrophobic core through hydrophobic interactions. The micelle-like structured nanoparticles loaded with guest molecules under weak alkaline conditions are structures that are stable with a weak interaction-covalent bond positive correlation. Under weak acidic conditions, the micelle-like structured nanoparticles are converted into mixed micelles and further lose the mixed micelle structure, thereby achieving the functional release of guest molecules regulated by pH. In the presence of an oxidant, the micelle-like structured nanoparticles can oxidatively decompose the covalent bond between the aromatic group and the boron atom to destroy the structure of the micelle-like structured nanoparticles, thereby achieving the functional release of guest molecules regulated by the oxidant.
8. The use according to claim 7, characterized in that: The guest molecules were verified by using hydrophobic dye molecules and water-soluble catechol molecules, and the oxidant was 1.0 mM H2O2.
9. The novel micelle-like structured nanoparticles of claim 1 have a certain broad spectrum in terms of the hydrophilic-hydrophobic properties of loading guest molecules, the borate ester that stabilizes the nanoparticle structure has an acid dissociation constant close to the physiological pH, and the concentration of the oxidant H2O2 used is close to the concentration of H2O2 overexpression in human cancerous cells. Such micelle-like structured nanoparticles can be used for the loading and targeted release of some anticancer drugs.