Polylactide/Nanohydroxyapatite Composite Films: Physicochemical Properties and Biocompatibility for Regenerative Medicine Applications

Introduction: Piezoelectric biomaterials are of significant interest for regenerative medicine due to their ability to stimulate cell proliferation and differentiation. Polylactide (PLA) is a bioresorbablepiezoelectric polymer classified by the FDA as GRAS, but its bioactivity is limited. Nanohydroxyapatite(nHA) has excellent osteoinductivity and biocompatibility. The aim of the study was to develop a PLA/nHA composite and comprehensively evaluate the effect of nHA addition on physico-chemical properties and biocompatibility.

Methods: nHA particles were synthesized by chemical precipitation at pH 9-11. The precipitate was washed and dried at 120°C. Composite materials in the form of films were obtained by irrigation from a solution. Granules of PLA weighing 0.5 g were dissolved in 14.3 ml of methylene chloride, 10 wt.% nHA was added, and the resulting suspension was poured into a Petri dish and naturally dried. The obtained films were characterized by FTIR, XPS, and DSC methods, and the wetting angle was measured. Biocompatibility was assessed using a resazurin test on osteosarcoma MG-63 cells for 24, 48, and 72 hours.

Results: FTIR spectra confirmed the successful incorporation of nHA into the PLA matrix by the characteristic bands of phosphate groups at 560, 600, and 1020 cm^-1. The DSC analysis showed that the addition of nHA slightly changes the thermophysical properties. XPS analysis revealed C-O, C=O, C-C, and O=C-O bonds in pure PLA, while Ca and P were not detected on the surface of PLA/nHA. With the introduction of nHA, the wetting angle decreased from 84.9° to 71.2°. The rezazurin test demonstrated the biocompatibility of PLA and PLA/nHA, with the viability of MG-63 cells > 70% at all time points.

Conclusions: PLA/nHA composite films have been successfully obtained. The addition of nHA improves the hydrophilicity of the surface and provides high biocompatibility, which is of interest for use in tissue engineering.