Coaxial electrospray of gentamicin sulfate-loaded micro/nano particles for sustained antibacterial PMMA bone cement

Polymethyl methacrylate (PMMA) bone cement is widely used in orthopedic surgery, and enhancing its antibacterial properties is crucial for preventing perioperative infections. In this study, unique “berry-shaped” micro/nano composite particles were prepared via coaxial electrospraying for the development of antibacterial PMMA bone cement. These particles consist of PMMA microspheres uniformly embedded with nanosilica (SiO 2 ) drug carriers coated with quaternary ammonium chitosan (HACC) and loaded with gentamicin sulfate (GS). Using a polylactic acid (PLA) nanofiber mat as the collection substrate, uniform assembly of the micro/nano composite particles and their strong anchoring to the matrix were achieved by tailoring the core-sheath solution properties and leveraging capillary-driven interactions. This hierarchical design not only improved interfacial adhesion to the PMMA bone cement matrix and improved flexural toughness, but also reduced the curing temperature. The corresponding antibacterial PMMA composite bone cement released GS sustainably for over five days, demonstrating potent antibacterial activity against both Escherichia coli ( E. coli ) and methicillin-resistant Staphylococcus aureus ( MRSA ), as well as good fibroblast biocompatibility. This study proposed an integrated “material-structure-assembly” strategy for the one-step fabrication of functional micro/nano composite particles, providing a new approach for the development of advanced biomedical materials.