Immunomodulatory effect of Ti-Cu alloy by surface nanostructure synergistic with Cu2+ release

Immunomodulatory and bone regenerative properties of copper/procyanidins-modified titanium surfaces

The inflammatory response triggered by the interaction between implants and macrophages is essential for bone regeneration around these implants. This study presents the application of dopamine hydrochloride to develop a copper and procyanidins coating on titanium surfaces to investigate its effects on bacterial inhibition, macrophage polarization, and osteogenic differentiation. The results demonstrated that this copper/procyanidins coating significantly suppressed the growth of Escherichia coli and Staphylococcus aureus. Notably, the initial release of Cu2+ ions promoted macrophage polarization toward a pro-inflammatory phenotype while stimulating the secretion of anti-inflammatory factors. Subsequently, the reduced Cu2+ release combined with procyanidins facilitated the transition from M1 to M2 macrophages-an essential process for bacterial phagocytosis and bone regeneration. Furthermore, this coating enhanced the secretion of osteogenic factors by bone marrow mesenchymal stem cells, enhancing their osteogenic differentiation and integration with bone tissue. These findings highlight the potential of copper/procyanidins coating in developing implant surfaces with immune-modulating and sustained antibacterial properties.

APTES-mediated Cu2(OH)3(NO3) nanomaterials on the surface of silicone catheters for abscess

Metal-based nanomaterials have remarkable bactericidal effects; however, their toxicity cannot be disregarded. To address this concern, we developed a simple synthesis route for antibacterial catheters using metal-based nanomaterials to reduce toxicity while harnessing their excellent bactericidal properties. The grafting agent (3-aminopropyl)triethoxysilane (APTES) forms -NH2 groups on the catheter surface, onto which copper ions form a nanomaterial complex known as Cu2(OH)3(NO3) (defined as SA-Cu). The synthesized SA-Cu exhibited outstanding contact antibacterial effects, as observed through scanning electron microscopy (SEM), which revealed cell membrane crumbing and bacterial rupture on the catheter surface. Furthermore, SA-Cu exhibited excellent biosafety characteristics, as evidenced by the cell counting kit-8 (CCK-8) assay, which showed no significant cytotoxicity. SA-Cu demonstrated sustained antimicrobial capacity, with in vivo experiments demonstrating over 99% bactericidal efficacy against methicillin-resistant Staphylococcus aureus (MRSA) for two weeks. The transcriptome sequencing results suggested that SA-Cu may exert its bactericidal effects by interfering with histidine and purine metabolism in MRSA. This study presents a straightforward method for synthesizing antimicrobial silicone catheters containing copper nanomaterials using copper ions.