An in vitro bioinspired approach to enhance the bioactivity of titanium implants via electrophoretic deposition and biomimetic mineralization of type i collagen

Objective

This study aims to explore the efficacy of Electrophoretic Deposition (EPD) for collagen type I coating on titanium implants and its subsequent mineralization to improve osseointegration and bone regeneration.

Methods

Titanium disks were prepared with a sandblasted, large grit and acid-etched (SLA) surface. EPD was employed to deposit collagen type I onto the titanium surfaces, followed by two modes of mineralization: extra-fibril mineralization (EFM) and inter-fibril mineralization (IFM). Then comprehensive in vitro studies were conducted including surface properties, cell proliferation, osteogenic differentiation, and inflammatory responses.

Results

EPD successfully deposited a uniform collagen layer on titanium surfaces. EFM resulted in deposition of larger, irregularly shaped crystals, while IFM produced controlled, helical fibril mineralization. IFM-treated surfaces exhibited enhanced cell viability, proliferation, and osteogenic differentiation. Both EFM and IFM surfaces triggered higher macrophage activation than SLA surfaces. While EFM primarily induced a stronger M1 pro-inflammatory response, IFM exhibited a more balanced macrophage polarization with upregulated M2 markers at later stages.

Conclusion

EPD, particularly when integrated with IFM, significantly enhances the bioactivity and osteogenic potential of collagen-coated titanium implants. This method surpasses traditional SLA surfaces by stabilizing the collagen layer and creating a biomimetic environment conducive to bone regeneration and healing through a balanced inflammatory response, offering a promising strategy to improve titanium implant performance.