Duration of electrochemical deposition affects the morphology of hydroxyapatite coatings on 3D-printed titanium scaffold as well as the functions of adhered MC3T3-E1 cells.

Abstract

The use of 3D-printed scaffolds in repairing bone defects remains unexplored. We aimed to determine whether the duration of electrochemical deposition (ECD) affects the properties of hydroxyapatite (HA) coatings on 3D-printed titanium (TI) scaffolds as well as the corresponding phenotype of MC3T3-E1 cells seeded on these surfaces. Five groups of HA-coated TI scaffolds were produced using different durations of ECD (0, 5, 10, 20, and 30 min) and examined under scanning electron microscopy (SEM). MC3T3-E1 cell adhesion to the HA-coated scaffolds and subsequent proliferation and viability were assessed using SEM, DAPI staining, EdU staining, and Alamar Blue assay, respectively. MC3T3-E1 cell expression of osteogenic genes was analyzed by fluorescence RT-PCR. On SEM, longer ECD durations resulted in more compact HA crystals of differing morphology coated onto the TI scaffolds. MC3T3-E1 cell adhesion differed among the five groups (p < 0.05), with the largest number of cells adhered to the scaffolds prepared with 30 min of ECD, followed by the group prepared with 20 min of ECD. However, the ECD duration of 20 min was associated with the highest cell viability and proliferation rate (both p < 0.05) as well as the highest mRNA expression levels of alkaline phosphatase, collagen I, osteocalcin and runt-related transcription factor 2 among the five groups (p < 0.05). In the fabrication of HA-coated 3D printed TI scaffolds, an ECD duration of 20 min resulted in scaffolds that best promoted MC3T3-E1 cell viability, proliferation and osteogenic gene expression.