Multifunctional Lactoferrin Coatings on PLA/HAp Microspheres for Antibacterial, Pro-Adhesive and Osteogenic Effect on MC3T3-E1 Cells

Modern biomaterials are increasingly expected to fulfill multiple functions simultaneously. The aim of this study was to develop multifunctional composite microspheres (MSs) based on poly(L-lactic acid) and hydroxyapatite (PLA/HAp), surface-modified with lactoferrin (Lf). The objective was to create a material exhibiting antimicrobial, pro-adhesive, and osteogenic properties for potential applications in modular tissue engineering. Microspheres with diameters ranging from 70 to 150 µm were fabricated using an oil-in-water emulsification method and subsequently coated with lactoferrin. Antimicrobial efficacy was evaluated against S. aureus, P. aeruginosa, and C. albicans by assessing bacterial adhesion, colony formation, and reduction rates. Osteoblast behavior, including adhesion and differentiation, was investigated using the MC3T3 cell line. The morphology of the samples was analyzed via optical and scanning electron microscopy. The results demonstrated that Lf-coated MSs exerted a significant antibacterial effect against S. aureus and P. aeruginosa. Furthermore, the presence of lactoferrin enhanced cell adhesion to the microspheres, as confirmed by the MTT assay after 24 h of incubation. On day 14, osteogenic differentiation was observed in cultures containing Lf-coated MSs, even in the absence of exogenous differentiating factors. Additionally, hematoxylin and eosin (H/E) staining revealed improved self-assembly of the Lf-modified microspheres. The reduction in microbial adhesion, coupled with enhanced osteoblast attachment, suggests a synergistic effect that may increase the success rate of implant integration at an early stage.