Sr3(PO4)2 particles as a factor for the formation of functional coating on titanium implant

The aim of this work is to analyze the usefulness of Sr3(PO4)2 as a potential antibacterial agent in fast-degradable polymer coatings. The Ti implant was anodized and then covered by a poly(adipic anhydride) layer blended with Sr3(PO4)2 particles by dip coating. The average size of the particles was 450 nm ± 53 nm (Zetasizer analysis), and phase analysis (X-ray diffractometer) showed mainly crystalline phases. Surface morphology and surface roughness were analyzed by scanning electron microscopy with energy dispersive X-ray (EDX). The oxide layer thickness on the implant surface was between 4.57 μm and 8.09 μm. The polymer layer with Sr3(PO4)2 particles was determined by confocal microscopy, and the average thickness was 25 μm. The contact angle of the anodized Ti implant alone was 37.3° ± 9.9° and decreased with time up to 20° after 1900s. After 1 h of implant immersion in Ringer solution, 42.15% of the Sr compound loaded in the polymer layer was released (determined by inductively coupled plasma atomic emission spectrometry (ICP-AES)). Fast degradation of the polymer caused 65.21% of the loaded Sr compound to be released from the implant surface after 24 h. The concentration of Sr3(PO4)2 was enough to significantly inhibit the adhesion of Staphylococcus aureus ATCC 25923 bacteria on the implant surface. The implant surface is cytocompatible with osteoblast-like MG-63 cells. The preliminary results of hybrid coating analysis showed that Sr3(PO4)2 may be used as an alternative ceramic material for the formation of a functional layer for orthopedic applications.