Titanium implants coated with UV‐irradiated vitamin D precursor and vitamin E: in vivo performance and coating stability

Abstract

This study aimed at evaluating the biological response of titanium implants coated with UV-irradiated 7-dehydrocholesterol (7-DHC) and vitamin E (VitE) invivo and analyzing the effects of aging on their stability and bioactivity invitro. Titanium surfaces were coated with 7-DHC and VitE, UV-irradiated and incubated for 48h at 23°C to allow cholecalciferol synthesis. The invivo biological response was tested using a rabbit tibia model after 8weeks of healing by analyzing the wound fluid and the mRNA levels of several markers at the bone-implant interface (N=8). The stability of the coating after storage up to 12weeks was determined using HPLC analysis, and the bioactivity of the stored modified implants was studied by an invitro study with MC3T3-E1 cells (N=6). A significant increase in gene expression levels of osteocalcin was found in the bone tissue attached to implants coated with the low dose of 7-DHC and VitE, together with a higher ALP activity in the wound fluid. Implants treated with the high dose of 7-DHC and VitE showed increased tissue necrosis and inflammation. Regarding the aging effects, coated implants were stable and bioactive up to 12weeks when stored at 4°C and avoiding oxygen, light and moisture. This study demonstrates that Ti implants coated with UV-irradiated 7-DHC and VitE promote invivo gene expression of bone formation markers and ALP activity, while they keep their osteopromotive potential invitro and composition when stored up to 12weeks at 4°C.