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.

Modifications on porous absorbable Fe-based scaffolds for bone applications: A review from corrosion and biocompatibility viewpoints.

Iron (Fe) and Fe-based scaffolds have become a research frontier in absorbable materials which is inherent to their promising mechanical properties including fatigue strength and ductility. Nevertheless, their slow corrosion rate and low biocompatibility have been their major obstacles to be applied in clinical applications. Over the last decade, various modifications on porous Fe-based scaffolds have been performed to ameliorate both properties encompassing surface coating, microstructural alteration via alloying, and advanced topologically order structural design produced by additive manufacturing (AM) techniques. The recent advent of AM produces topologically ordered porous Fe-based structures with an optimized architecture having controllable pore size and strut thickness, intricate internal design, and larger exposed surface area. This undoubtedly opens up new options for controlling Fe corrosion and its structural strengths. However, the in vitro biocompatibility of the AM porous Fe still needs to be addressed considering its higher corrosion rate due to the larger exposed surface area. This review summarizes the latest progress of the modifications on porous Fe-based scaffolds with a specific focus on their responses on the corrosion behavior and biocompatibility.

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.

Degradation-triggered release from biodegradable metallic surfaces.

This work is dedicated to the investigation of drug-release control by a direct effect of degradation from biodegradable metallic surfaces. Degradation behaviors characterized by surface morphology, immersion, and electrochemical techniques demonstrated that curcumin-coated zinc (c-Zn) had a higher degradation rate compared to curcumin-coated Fe (c-Fe). High anodic dissolution rate due to the higher degradation rate and widely extended groove-like degradation structure of c-Zn propelled a higher curcumin release. On the other hand, a slower curcumin release rate shown by c-Fe scaffolds is ascribed to its lower anodic dissolution and to its pitting degradation regime with relatively smaller pits. These findings illuminate the remarkable advantage of different degradation behaviors of degradable metallic surfaces in directly controlling the drug release without the need for external electrical stimulus.