Self-mineralization antibacterial aggregate adhesive and application thereof

Abstract

The invention belongs to the field of bone repair, and particularly relates to a self-mineralization antibacterial aggregate adhesive and application thereof. Polyallylamine hydrochloride with positive charges and polyacid salt with negative charges are mainly used as raw materials, a condensation body is formed in a positive and negative charge cross-linking physical mode, and the polyacid salt is at least one of tripolyphosphate, polyaspartate and polysilicate. The self-mineralization antibacterial aggregate adhesive has excellent injectability and shape adaptability, can effectively fix small-size and irregular-shape fracture fragments, remarkably improves biocompatibility, adhesion strength, osteogenesis performance and antibacterial ability, and comprehensively overcomes many limitations of a traditional adhesive in bone repair.

Description

Technical Field

[0001] The invention belongs to the field of bone repair, and in particular relates to a self-mineralizing antibacterial aggregate adhesive and application thereof. Background Art

[0002] In clinical practice, comminuted fractures often result in small, irregularly shaped fracture fragments. Internal fixation is currently the most common treatment. However, metal internal fixation devices can increase surgical incisions and cause additional surgical trauma. Without fixation, minute movement of the fragments can interfere with fracture healing, leading to delayed union or nonunion. Therefore, a simple and effective fixation method for these fracture fragments is lacking. Currently, adhesives are widely used in medicine due to their ease of use and reliable bonding. Existing adhesives are primarily synthetic and naturally derived. Synthetic adhesives are subject to cytotoxicity due to the byproducts produced during their synthesis and the extreme reaction conditions they face. Naturally derived adhesives exhibit excellent biocompatibility. However, their adhesion strength is significantly lower than that of synthetic adhesives. Therefore, current synthetic and naturally derived adhesives are unsuitable for bone fragment fixation, and a new type of bone adhesive is urgently needed for this purpose.

[0003] An ideal bone adhesive should be injectable, form-fitting, and possess good adhesion, biocompatibility, antibacterial properties, and osteogenic properties. CN107343965A discloses a bone adhesive whose raw materials include an α-cyanoacrylate compound and bioactive particles. According to the invention, the bioactive particles can form a mineralized layer in body fluids, exhibiting both osteoinductivity and osteoconductivity. However, this invention still suffers from a number of issues, including poor bone fragment fixation and low adhesion strength.

[0004] CN113577371A discloses an organic-inorganic hybrid hydrogel bone adhesive. This adhesive is prepared by uniformly mixing inorganic and aldehyde polysaccharides to form a pre-crosslinked solution, which is then reacted in situ with an amino polysaccharide buffer solution to form an organic-inorganic hybrid hydrogel with a three-dimensional porous structure. This hybrid hydrogel exhibits enhanced adhesion and mechanical properties, further promoting bone healing and repairing bone tissue. However, the initial reaction of the polysaccharide polymer with sodium periodate to generate the toxic aldehyde polysaccharide poses certain risks, and its anti-infection properties are insufficient, limiting its application value.

[0005] Recently, aggregates have garnered significant attention and are expected to become the next generation of bone adhesives. Aggregates are formed by the binding of oppositely charged macromolecules through non-covalent interactions (such as electrostatic, hydrophobic, and hydrogen bonding) through liquid phase separation. Consequently, aggregate synthesis exhibits minimal side reactions and excellent biocompatibility. These interactions also confer injectability, shape adaptability, and good adhesion to aggregates. However, aggregates often lack osteogenic properties, which limits their application as bone adhesives. Researchers have proposed various approaches to improve the osteogenic properties of aggregates. For example, minerals are dispersed into aggregate precursor solutions. However, this step often results in uneven distribution of the minerals within the adhesive, leading to a mismatch in mechanical properties between the hard mineral and the soft polymer matrix, potentially compromising aggregate adhesive properties such as injectability and shape adaptability. Therefore, there is an urgent need to identify new and innovative preparation strategies to further address the interface mismatch in mineralized aggregates and maintain their performance.

[0006] Antimicrobial properties are also crucial for bone adhesives. Adhesives without antimicrobial properties are easily attached to bacteria and form biofilms on their surfaces, seriously threatening bone repair and anti-infective treatment. Antibiotics are the mainstay of antimicrobial therapy for bone adhesives. However, their overuse can lead to increased bacterial resistance and significantly impede bone healing. Therefore, further research and development of bone adhesives with superior performance is crucial. Summary of the Invention

[0007] In summary, current adhesives exhibit problems such as being unsuitable for bone fragment fixation, poor biocompatibility, low adhesion strength, insufficient osteogenic properties, and still lacking anti-infection properties. The present invention addresses these issues by preparing a self-mineralizing antibacterial aggregate adhesive.

[0008] In order to solve the above-mentioned technical problems, this application provides the following technical solutions:

[0009] The present invention provides a self-mineralizing antibacterial aggregate adhesive, which is obtained by mixing an aqueous solution of polyacrylamine hydrochloride and an aqueous solution of a polyacid salt, followed by solid-liquid separation. The adhesive primarily uses positively charged polyacrylamine hydrochloride and negatively charged polyacid salt as raw materials, and forms the aggregate through a physical process of positive and negative charge crosslinking.

[0010] Preferably, the polyacid salt is selected from one or more of sodium tripolyphosphate, sodium polyaspartate and sodium polysilicate.

[0011] Preferably, the molar ratio of the polyacrylamine hydrochloride to the polyacid salt is 4-6:1.

[0012] Preferably, the aqueous solution of polyacrylamine hydrochloride and the aqueous solution of the polyacid salt are both adjusted to neutrality before mixing.

[0013] Preferably, the solid-liquid separation method is centrifugation.

[0014] Preferably, after the solid-liquid separation, the sample is immersed in a PBS solution and then taken out.

[0015] Furthermore, the immersion time is 10-14 hours.

[0016] Preferably, the concentration of the solute in the aqueous solution of polyacrylamine hydrochloride is 150-160 g / L, and the concentration of the solute in the aqueous solution of the polyacid salt is 120-130 g / L.

[0017] Specifically, the preparation method of the self-mineralizing antibacterial aggregate adhesive comprises the following steps:

[0018] The polyacrylamine hydrochloride solution and the polyacid salt solution are prepared in a molar ratio of 5:1, and the pH of the polyacrylamine hydrochloride solution and the polyacid salt solution is adjusted to 7 using a sodium hydroxide solution and a dilute hydrochloric acid solution. The polyacrylamine hydrochloride solution and the polyacid salt solution are mixed, centrifuged after mixing, and immersed in PBS for 12 hours before being taken out.

[0019] The present invention also provides application of the self-mineralized antibacterial aggregate adhesive in bone repair in vivo.

[0020] Preferably, the in vivo bone repair time is 7-9 weeks.

[0021] The technical solution of the present invention has the following advantages over the prior art:

[0022] Compared with the existing technology, the self-mineralizing antibacterial aggregate adhesive prepared by the present invention has better injectability, shape adaptability, adhesion, antibacterial and self-mineralization properties, providing a better choice for the preparation of new bone adhesives, so that it can meet the needs of clinical bone fragment fixation. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The polyacrylamine hydrochloride-sodium tripolyphosphate aggregate in Example 1 has injectability.

[0024] Figure 2 This is a diagram showing the shape adaptability of the polyacrylamine hydrochloride-sodium tripolyphosphate coacervate in Example 1.

[0025] Figure 3 This is a schematic diagram showing that the polyacrylamine hydrochloride-sodium tripolyphosphate aggregate in Example 1 can adhere to various orthopedic implants and bone fragments.

[0026] Figure 4 This is a characterization diagram of the broad-spectrum antibacterial performance of the polyacrylamine hydrochloride-sodium tripolyphosphate aggregate in Example 1.

[0027] Figure 5 Micro-CT reconstructed images of cyanoacrylate adhesive and polyacrylamine hydrochloride-sodium tripolyphosphate coacervate adhesive in Example 1 implanted for different days.

[0028] Figure 6 Graphs showing the in vivo bone repair effects of cyanoacrylate adhesive and the polyacrylamine hydrochloride-sodium tripolyphosphate aggregate adhesive in Example 1 after 8 weeks. DETAILED DESCRIPTION

[0029] The present invention will be further described below with reference to the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it. However, the embodiments are not intended to limit the present invention.

[0030] Example 1

[0031] Preparation of coacervates using positively charged polyacrylamine hydrochloride and negatively charged polyacid salts as raw materials.

[0032] In this embodiment, positively charged polyacrylamine hydrochloride (chemical formula (C3H8ClN)n, CAS No. 71550-12-4) and negatively charged polyacid salts were used as raw materials to form aggregates through physical cross-linking of positive and negative charges, wherein the polyacid salt was sodium tripolyphosphate.

[0033] Polyacrylamine hydrochloride and polyacid salt are prepared at a molar ratio of 5:1 and added into water respectively to form a polyacrylamine hydrochloride solution with a concentration of 156.33 g / L and a polyacid salt solution with a concentration of 122.67 g / L.

[0034] The pH of the polyacrylamine hydrochloride solution and the polyacid salt solution were adjusted to 7 using sodium hydroxide solution and dilute hydrochloric acid solution, and the polyacrylamine hydrochloride solution and the polyacid salt solution of the same pH were mixed. After mixing, the mixture was centrifuged at a speed of 1500 rpm for 15 minutes and immersed in PBS for 12 hours before being taken out to obtain a polyacrylamine hydrochloride-polyacid salt coacervate adhesive.

[0035] Example 2

[0036] Preparation of coacervates using positively charged polyacrylamine hydrochloride and negatively charged polyacid salts as raw materials.

[0037] In this embodiment, positively charged polyacrylamine hydrochloride and negatively charged polyacid salt are used as raw materials to form aggregates through a physical method of positive and negative charge cross-linking, wherein the polyacid salt is sodium polyaspartate.

[0038] Polyacrylamine hydrochloride and polyacid salt are prepared at a molar ratio of 5:1 and added into water respectively to form a polyacrylamine hydrochloride solution with a concentration of 156.33 g / L and a polyacid salt solution with a concentration of 122.67 g / L.

[0039] The pH of the polyacrylamine hydrochloride solution and the polyacid salt solution were adjusted to 7 using sodium hydroxide solution and dilute hydrochloric acid solution, and the polyacrylamine hydrochloride solution and the polyacid salt solution of the same pH were mixed. After mixing, the mixture was centrifuged at a speed of 1500 rpm for 15 minutes and immersed in PBS for 12 hours before being taken out to obtain a polyacrylamine hydrochloride-polyacid salt coacervate adhesive.

[0040] Example 3

[0041] Preparation of coacervates using positively charged polyacrylamine hydrochloride and negatively charged polyacid salts as raw materials.

[0042] In this embodiment, positively charged polyacrylamine hydrochloride and negatively charged polyacid salt are used as raw materials to form aggregates through a physical method of positive and negative charge cross-linking, wherein the polyacid salt is sodium polysilicate.

[0043] Polyacrylamine hydrochloride and polyacid salt are prepared at a molar ratio of 5:1 and added into water respectively to form a polyacrylamine hydrochloride solution with a concentration of 156.33 g / L and a polyacid salt solution with a concentration of 122.67 g / L.

[0044] The pH of the polyacrylamine hydrochloride solution and the polyacid salt solution were adjusted to 7 using sodium hydroxide solution and dilute hydrochloric acid solution, and the polyacrylamine hydrochloride solution and the polyacid salt solution of the same pH were mixed. After mixing, the mixture was centrifuged at a speed of 1500 rpm for 15 minutes and immersed in PBS for 12 hours before being taken out to obtain a polyacrylamine hydrochloride-polyacid salt coacervate adhesive.

[0045] Application Examples

[0046] The in vivo bone repair performance and application of polyacrylamine hydrochloride-polyacid salt aggregate adhesive are as follows:

[0047] The preparation process of the polyacrylamine hydrochloride-sodium tripolyphosphate coagulant adhesive is the same as that in Example 1.

[0048] In this application example, an infectious rat skull comminuted fracture model was constructed and the bone repair effects of different adhesives were observed by Micro-CT 8 weeks after surgery. Figure 6 As shown in the results, polyacrylamine hydrochloride-polyacid salt coacervate adhesive has better repair effect.

[0049] Effect evaluation 1

[0050] like Figure 1 As shown, the polyacrylamine hydrochloride-sodium tripolyphosphate aggregate prepared in Example 1 is injectable.

[0051] like Figure 2 As shown, the polyacrylamine hydrochloride-sodium tripolyphosphate coacervate has shape adaptability.

[0052] like Figure 3 As shown in the results, polyacrylamine hydrochloride-sodium tripolyphosphate aggregates can adhere to various orthopedic implants and firmly fix bone fragments.

[0053] Effect evaluation 2

[0054] The broad-spectrum antibacterial properties of polyacrylamine hydrochloride-polyacid salt aggregates are studied as follows:

[0055] Figure 4 The broad-spectrum antibacterial properties of the polyacrylamine hydrochloride-polyacid salt aggregates prepared in Example 1 were studied. The polyacrylamine hydrochloride component of the aggregates carries a large amount of positive charge, which can bind to the negative charge on the surface of bacterial cell membranes to exert antibacterial properties. The broad-spectrum antibacterial properties of the aggregates were studied using plate coating experiments on Staphylococcus aureus, Escherichia coli, and methicillin-resistant Staphylococcus aureus (resistant bacteria). The results of the present invention demonstrate that the polyacrylamine hydrochloride-sodium tripolyphosphate aggregates possess excellent broad-spectrum antibacterial properties.

[0056] Effect evaluation 3

[0057] The self-mineralization performance of polyacrylamine hydrochloride-polyacid salt aggregates is studied as follows:

[0058] In Example 1, polyacrylamine hydrochloride-sodium tripolyphosphate aggregates were synthesized. The sodium tripolyphosphate component of the aggregates has a strong calcium ion chelating ability and can achieve self-mineralization in vivo. The present invention compared the mineralization effects of clinically used cyanoacrylate adhesives and polyacrylamine hydrochloride-sodium tripolyphosphate aggregates by constructing a subcutaneous implantation model in nude mice, and analyzed their self-mineralization properties by Micro-CT (micro CT detection). Figure 5 shown.

[0059] The study found that polyacrylamine hydrochloride-sodium tripolyphosphate aggregates have excellent self-mineralization properties.

[0060] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A self-mineralizing antibacterial aggregate adhesive, characterized in that: The product is obtained by mixing an aqueous solution of polyacrylamine hydrochloride and an aqueous solution of a polyacid salt and then performing solid-liquid separation.

2. The self-mineralizing antibacterial aggregate adhesive according to claim 1, characterized in that: The polyacid salt is selected from one or more of sodium tripolyphosphate, sodium polyaspartate and sodium polysilicate.

3. The self-mineralizing antibacterial aggregate adhesive according to claim 1, characterized in that: The molar ratio of the polyacrylamine hydrochloride to the polyacid salt is 4-6:

1.

4. The self-mineralizing antibacterial aggregate adhesive according to claim 1, characterized in that: Before the mixing, the aqueous solution of polyacrylamine hydrochloride and the aqueous solution of the polyacid salt are both adjusted to neutral.

5. The self-mineralizing antibacterial aggregate adhesive according to claim 1, characterized in that: The solid-liquid separation method is centrifugation.

6. The self-mineralizing antibacterial aggregate adhesive according to claim 1, characterized in that: After the solid-liquid separation, the sample was immersed in a PBS solution and then taken out.

7. The self-mineralizing antibacterial aggregate adhesive according to claim 6, characterized in that: The immersion time is 10-14 hours.

8. The self-mineralizing antibacterial aggregate adhesive according to claim 1, characterized in that: The solute concentration in the aqueous solution of polyacrylamine hydrochloride is 150-160 g / L, and the solute concentration in the aqueous solution of polyacid salt is 120-130 g / L.

9. Use of the self-mineralizing antibacterial aggregate adhesive according to any one of claims 1 to 8 in bone repair in vivo.

10. Use of the self-mineralizing antibacterial aggregate adhesive in in vivo bone repair according to claim 9, characterized in that: The in vivo bone repair time is 7-9 weeks.

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