可降解锌基骨植入材料及其表面改性研究进展OACSTPCD

In recent years,biodegradable metals,represented by magnesium(Mg),zinc(Zn),and iron(Fe),have received extensive attention from the biomedical and materials fields both domestically and internationally.This article outlined the requirements for ideal bone implant materials,and the advantages of biodegradable metals over other biodegradable materials,including mechanical performance,degradation performance,and biocompatibility.In addition,the degradation mechanism of biodegradable metal materials was summarized.Among them,Mg had been extensively investigated,but its rapid degradation rate lead to compromised mechanical properties and uncontrolled hydrogen evolution.Conversely,the degradation rate of Fe was notably sluggish,approaching that of non-degradable materials.Zn and Zn alloys,due to their moderate degradation rate,good mechanical properties,and biological safety,were expected to become a new generation of biodegradable bone implant materials to promote bone defect repair.This article summarized the advantages of biodegradable Zn-based materials,including biological safety,antibacterial effects,and the ability to promote the generation of blood vessels and new bone around the implant site,as well as to promote the expression of bone-related genes.Based on this,recent research on the biocompatibility and degradation behavior of biodegradable Zn-based materials was systematically summarized from the aspects of substrate materials,cell types,and experimental results.At the same time,the main problems and challenges faced by the clinical application of biodegradable Zn for repairing bone defects were summarized,including poor mechanical properties and strong cytotoxicity.The poor mechanical properties of biodegradable Zn could be improved through alloying.This article outlined the mechanical properties and biocompatibility of various new medical Zn alloys.The potent cytotoxicity of biodegradable Zn used in medical applications arose from the local accumulation of Zn2+ ion generated during degradation.Zn2+ ion was reported to exhibit biphasic effect on cells.The low concentration of Zn2+ ion could promote the cell adhesion,proliferation,and differentiation.In contrast,the local high concentration of Zn2+ ion resulted from the rapid degradation rate of Zn implants at the initial stage of implantation,and some degradation products such as ZnO and Zn(OH)2 with poor biocompatibility always lead to cytotoxicity and inflammation surrounding the Zn implants,further delaying the regeneration and repair of bone defects.Zn still exhibited slight cytotoxicity after alloying,and surface modification was an effective means to improve the surface biocompatibility and regulate degradation of biodegradable Zn.This article reviewed the current research status of surface modi-fication of biodegradable Zn-based bone implant materials from the aspects of substrate samples,surface modification methods,cell or animal models used,and cell compatibility and degradation behavior,and proposed the current difficulties and future development directions of surface modification of biodegradable Zn-based bone implant materials.Surface modification of biodegradable Zn is still nascent,and there are scarce relevant studies with restricted advancement in the biocompatibility of biodegradable Zn.Traditional surface modification methods have increased the release of Zn2+ ion,resulting in higher cyto-toxicity.Alternatively,the efficacy of improving the biocompatibility of biodegradable Zn through surface modification has been insufficient.The future research direction of biodegradable Zn-based materials should focus more on surface modification methods such as phosphate and its composite coatings,as well as biodegradable polymer coatings.