Chitosan-vancomycin Hydrogel Incorporated Bone Repair Scaffold Based On Staggered Orthogonal Structure

Objective:This investigation focused on developing an antibacterial scaffold for tissue-engineered bone by constructing a sustained-release system featuring vancomycin-chitosan hydrogel(CS-Van)loaded polylactic acid/nano-hydroxyapatite(PLA/nHA)scaffold.In particular,the physicochemical,sustained-release,cell compatibility,and antibacterial properties of the drug-loaded composite scaffold were evaluated to enhance its effectiveness.The outcome of this study is expected to provide a new modality to address antibiotic-resistant infections in bone tissue engineering.Methods:1.Preparation and characterization analysis of CS-Van hydrogel: An ion crosslinking method was used to load vancomycin(Van)onto chitosan(CS)hydrogel to prepare a sustained-release carrier called CS-Van.The surface structure was studied via scanning electron microscopy(SEM).Moreover,X-ray photoelectron spectroscopy(XPS),Fourier transform infrared spectroscopy(FTIR),and X-ray diffraction(XRD)methods were employed to analyze the constituent elements of the carrier.2.Preparation and performance study of PLA/nHA/CS-Van drug-loaded composite scaffolds: two types of scaffolds with different geometric configurations,PLA/nHA vertical orthogonal(S1)and PLA/nHA staggered orthogonal(S2),were prepared using3 D printing technology,with polylactic acid(PLA)and nano-hydroxyapatite(nHA)as raw materials.CS-Van hydrogel was loaded onto the scaffolds to prepare PLA/nHA/CSVan vertical orthogonal(S3)and PLA/nHA/CS-Van staggered orthogonal(S4)drugloaded scaffold,establishing a dual drug release system.The scaffolds were characterized by SEM and tested for mechanical properties,drug release,biocompatibility,and antibacterial effects.The results showed that the scaffolds exhibited a sustained drug release effect,good biocompatibility,and antibacterial properties.These findings suggest the potential of PLA/nHA/CS-Van drug-loaded composite scaffolds as a promising therapeutic option in the field of clinical treatment.Results:1.The SEM findings demonstrate a three-dimensional network structure with a rough surface and irregular Van particles on the surface of the CS-Van hydrogel.Additionally,FTIR and XPS analyses reveal the characteristic peaks of both Van and CS in the hydrogel.XRD results show that the spectrum is a sum of a broad CS band and sharp Van peaks,indicating the successful loading of Van onto CS.2.In terms of structure,the low-magnification SEM images depict comparable porous interconnections in all the scaffolds with distinct pore sizes,the high-magnification SEM images illustrate that the surfaces of scaffolds in groups S1 and S2 are relatively even,while those in groups S3 and S4 exhibit water gel build-up in the gaps of scaffold connections,thereby increasing the surface roughness.EDS spectrum analysis confirms the presence of characteristic elements of PLA,nHA,CS,and Van in S3 and S4.The findings demonstrate that incorporating CS-Van hydrogel into the composite scaffold has aided in enhancing its mechanical properties.The in vitro release experiments show that the cumulative release rates of CS-Van,S3,and S4 scaffolds progressively increased over time,(90±3.3)%,(75±4.1)%,and(64.7±3.6)% on the 15 th day,and(93.5±3.6)%,(84.3±4.3)%,and(73.8±3.8)% on the 30 th day,respectively.According to cell experiments,the scaffold displayed promising cell compatibility as the cell count increased with time compared to the control group(P< 0.05),with DAPI staining images confirming good cell compatibility.Furthermore,the results of the antibacterial experiment revealed significant antibacterial activity in the S3 and S4 groups.Overall,these results confirm the efficacy of the CS-Van hydrogel and suggest its potential as an innovative solution for improving scaffold technology.Conclusions:1.The PLA/nHA/CS-Van intercalated orthogonal structure has superior 3D structural controllability and antibacterial properties compared to traditional perpendicular orthogonal structures.2.The mechanical and drug release antibacterial performance of the drug-loaded composite scaffold can meet the requirements for building tissue engineering bone scaffolds.