Degradation-triggered release from biodegradable metallic surfaces

Evaluation of in vitro corrosion behavior and biocompatibility of poly[xylitol-(1,12-dodecanedioate)](PXDD)-HA coated porous iron for bone scaffolds applications

The present study evaluates the corrosion behavior of poly[xylitol-(1,12-dodecanedioate)](PXDD)-HA coated porous iron (PXDD140/HA-Fe) and its cell-material interaction aimed for temporary bone scaffold applications. The physicochemical analyses show that the addition of 20 wt.% HA into the PXDD polymers leads to a higher crystallinity and lower surface roughness. The corrosion assessments of the PXDD140/HA-Fe evaluated by electrochemical methods and surface chemistry analysis indicate that HA decelerates Fe corrosion due to a lower hydrolysis rate following lower PXDD content and being more crystalline. The cell viability and cell death mode evaluations of the PXDD140/HA-Fe exhibit favorable biocompatibility as compared to bare Fe and PXDD-Fe scaffolds owing to HA's bioactive properties. Thus, the PXDD140/HA-Fe scaffolds possess the potential to be used as a biodegradable bone implant.

Insight into the bioabsorption of Fe-based materials and their current developments in bone applications

Iron (Fe) and Fe-based materials have been vigorously explored in orthopedic applications in the past decade mainly owing to their promising mechanical properties including high yield strength, elastic modulus and ductility. Nevertheless, their corrosion products and low corrosion kinetics are the major concerns that need to be improved further despite their appealing mechanical strengths. The current studies on porous Fe-based scaffolds show an improved corrosion rate but the in vitro biocompatibility is still problematic in general. Unlike the Mg implants, the biodegradation and bioabsorption of Fe-based implants are still not well described. This vague issue could implicate the development of Fe-based materials as potential medical implants as they have not reached the clinical trial stage yet. Thus, there is a need to understand in-depth the Fe corrosion behavior and its bioabsorption mechanism to facilitate the material design of Fe-based scaffolds and further improve its biocompatibility. This manuscript provides an important insight into the basic bioabsorption of the multi-ranged Fe-based corrosion products with a review of the latest progress on the corrosion & in vitro biocompatibility of porous Fe-based scaffolds together with the remaining challenges and the perspective on the future direction.