Zwitterion polymer-modified graphene oxides enhance antibacterial activity with improved biocompatibility and osteogenesis: An in vitro study

This study utilized surface-initiated atom transfer radical polymerization (SI-ATRP) to graft the zwitterionic polymer poly(carboxybetaine methacrylate) (PCBMA) onto graphene oxide (GO) (GO/PCBMA), enhancing its physicochemical properties and biomedical potential. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) confirmed successful grafting, while thermogravimetric analysis (TGA) indicated a PCBMA loading of 0.54 mg/mg GO. Gel permeation chromatography (GPC) showed a monomer conversion efficiency of similar to 40 %, demonstrating good polymerization control. GO/PCBMA exhibited superior antibacterial performance, reducing Streptococcus mutans viability by 87.6 % at 80 mu g/mL within 5 h, while GO required 160 mu g/mL to achieve a 78.3 % reduction. Long-term antibacterial effects were further validated through three-day colony-forming unit (CFU) counts. GO/PCBMA also improved L929 fibroblast viability and promoted osteogenic differentiation in human bone marrow mesenchymal stem cells (hBMMSCs), as evidenced by increased alkaline phosphatase (ALP) activity and osteocalcin (OCN) expression. These findings highlight GO/PCBMA as a promising material for applications requiring both antibacterial activity and biocompatibility, particularly for long-term biomedical implants. This study provides insights for the development of multifunctional graphene oxide-based biomaterials.