Cleaning and coating procedures determine biological properties of gyroid porous titanium implants

Cleaning and coating processes as well as biocompatibility of gyroid commercially pure titanium (Cp-Ti) biomedical implants using the laser powder bed fusion (L-PBF) technology were analyzed. Etching time for cleaning of gyroid Cp-Ti biomedical implants were determined to remove non-melted particles from the surface. Nano hydroxyapatite (nHA) and polylactic acid (PLA) composite coating on the gyroid Cp-Ti implants via dip coating were optimized. Dip coating's withdrawal speed also, the amount of nHA:PLA and viscosity effects of composite were evaluated. 1000 mm/min withdrawal speed prevented clogging of the pores. In addition, silk fibroin was coated on gyroid Cp-Ti implants with electro deposition method. Optimum coating thicknesses were achieved. Biocompatibility after PLA:nHA and silk fibroin were studied. Gyroid and solid Cp-Ti presented 3% and 1% mass loss after a minute of HF/HNO3 etching. The three-minute etching protocol led to the highest micro pit width formation on the surfaces. 70:30 PLA:nHA and silk fibroin established crack-free coatings on gyroid Cp-Ti surfaces. MTT, live-dead cell assay revealed good biocompatibility after coating.