Poly(d,l-lactide)-grafted Cu-doped bioactive glass microspheres as core–shell building blocks for biomaterials: from grafting to early-stage in vitro behaviour

Abstract

Freeze-casting enables the fabrication of porous scaffolds for bone reconstruction, but the homogeneous dispersion of bioactive glass (BG) in polymer solutions remains challenging. Here, we report, for the first time, the synthesis of core–shell microparticles combining Cu-doped BG with poly(D,L-lactide) (PDLLA) grafted via a surface-initiated “grafting from” approach. Covalent grafting was confirmed by FT-IR spectroscopy and TGA analyses, with grafted chain lengths close to theoretical values. In simulated body fluid (SBF), the PDLLA corona temporarily delayed glass degradation and ion release, mitigating the initial “burst effect”, particularly for Cu²⁺. In vitro, all samples displayed dose-dependent antibacterial and cytotoxic responses, but PDLLA-grafted particles improved cell viability while preserving antibacterial activity. Notably, PDLLA-BG5 achieved the best balance between bacterial inhibition and cytocompatibility. These polymer-grafted, Cu-doped BG microspheres represent promising candidates as building blocks for future PDLLA-based scaffold fabrication via freeze-casting approaches, with scalable processing and tuneable ion-release-driven biological responses.