Promoting surgical pin performance: Chitosan and hydroxyapatite -based nano-composite coatings for antimicrobial and corrosion protection

• A novel Ch/ZnO-nHA nanocomposite coating is developed for surgical staple pins to improve their performance. • Corrosion resistance of coated staple pins is significantly enhanced, with a >70% reduction in corrosion rate. • Coated staple pins demonstrate potent antibacterial activity, showing >1 log reduction of E. coli and S. aureus . • This multifunctional coating effectively mitigates both corrosion and infection risks in surgical staples. This study aims to develop and coat a multifunctional composite coating onto the stainless-steel staple pins (SS-316L) to impart antibacterial and anticorrosive characteristics. The polymeric nanocomposite coating is comprised of chitosan/Zinc oxide-nanohydroxyapatite (Ch/ZnO-nHA). Electrophoretic deposition (EPD) was used to coat the Surgical staple pins (SSPs) with ZnO nanoparticles while nHA was encapsulated in the Ch matrix. Scanning electron microscope (SEM) analysis was performed to evaluate the morphology of the polymeric composite as well as to analyze the uncoated and coated SSPs. FTIR analysis was used to verify the presence of newly added polymeric functional groups. An X-ray Diffraction analysis was carried out to determine the size of crystallites. The electrochemical corrosion test demonstrated that the CS/ZnO-nHA coating significantly increased the corrosion resistance because of the shielding effect of the polymeric coating in the Simulated body fluid solution lowering the Icorr value from (3.160 µA) all the way down to (1.040 µA). In terms of antibacterial inhibition properties, the polymeric composite coating on staple pins showed a promising (1.023 log) reduction against Escherichia coli and (0.986 log) reduction against Staphylococcus aureus in just second dilution. These results confirmed that an increase in the corrosion resistance of the SSP and a reduction in surgical site infections can be achieved using the multifunctional chitosan-based nHA/ZnO nanocomposites for biomedical applications.