Electrophoretic deposition of TiO2 doped amine-grafted mesoporous bioactive glass on 3D-printed poly(L-lactic acid)/reduced graphene oxide scaffolds for bone tissue regeneration.

Three-dimensional (3D) printed scaffolds surface-coated with bioactive elements are considered promising candidates for bone regeneration due to their ability to replicate the porous architecture and chemical composition of the natural bone's extracellular matrix. This study presents a novel technique for the Electrophoretic deposition (EPD) of amine-grafted mesoporous bioactive glass (NM) and TiO2-doped amine-grafted mesoporous bioactive glass (NMTi) on the surface activated Poly(L-lactic acid) (PLA) based surface. Initially, PLA and PLA/reduced graphene oxide (PLAG)-based scaffolds were fabricated due to their superior mechanical and biological properties by coating 0.2% rGO onto PLA pellets, followed by filament extrusion and pelletisation process to prepare feedstock for the 3D printer. The scaffolds were fabricated using a thermal extrusion-based 3D printing technique and subsequently surface-activated with alkali treatment for effective EPD coating. The surface coating process was done using a three-electrode system with NM/NMTi dispersed in ethanol as the electrolyte solution at 70 °C under applied potentials of 1 and 4 V. SEM and XPS analysis were used to characterise the effect of applied potential on the surface coating on scaffolds. The PLAG based EPD coated scaffolds were examined for in vitro bioactivity assay using FESEM analysis. Additionally, the effects of surface coating with NM and NMTi were examined for the proliferation and differentiation of osteoblast-like cells (MG-63 cells). The EPD surface-coated scaffolds show better cell adhesion and proliferation rate, examined up to 14 days of culture period. With alkaline phosphatase activity, alizarin red staining, and gene expression analysis, it was observed that the incorporation of TiO2 in the MBG framework helps in accelerating the osteogenic differentiation ability.