A review on current research status of the surface modification of Zn-based biodegradable metals

Abstract

Recently, zinc and its alloys have been proposed as promising candidates for biodegradable metals (BMs), owning to their preferable corrosion behavior and acceptable biocompatibility in cardiovascular, bone and gastrointestinal environments, together with Mg-based and Fe-based BMs. However, there is the desire for surface treatment for Zn-based BMs to better control their biodegradation behavior. Firstly, the implantation of some Zn-based BMs in cardiovascular environment exhibited intimal activation with mild inflammation. Secondly, for orthopedic applications, the biodegradation rates of Zn-based BMs are relatively slow, resulting in a long-term retention after fulfilling their mission. Meanwhile, excessive Zn 2+ release during degradation will cause in vitro cytotoxicity and in vivo delayed osseointegration. In this review, we firstly summarized the current surface modification methods of Zn-based alloys for the industrial applications. Then we comprehensively summarized the recent progress of biomedical bulk Zn-based BMs as well as the corresponding surface modification strategies. Last but not least, the future perspectives towards the design of surface bio-functionalized coatings on Zn-based BMs for orthopedic and cardiovascular applications were also briefly proposed.

Surface Modification of Poly(lactic acid) Film via Cold Plasma Assisted Grafting of Fumaric and Ascorbic Acid

“…Surface modification methods can be physical or chemical, and there are a variety of treatments available. Over the last few decades, these modification methods have been established with an emphasis on the surface incorporation of extra functionalities responsible for the growing increase of surface free energy (wettability) and tailored applications [25][26][27]. Such modifications should only affect the top surface area (tens of nm), which is essential for functional strength and at the same time to maintain integrity of the material.…”

Special Features of Polyester-Based Materials for Medical Applications

“…Usually, materials used to repair bone defects are metallic biomaterials [ 36 , 37 ], bioceramics [ 38 , 39 ], and natural and synthetic polymers [ 40 , 41 ]. Hydroxyapatite (HA; (Ca 10 (PO 4 ) 6 (OH) 2 )) has been used as filler in polymer composites to improve the biocompatibility, mechanical strength, and porosity of biomaterials due to its similarity in structure and composition to bone and enamel, or to create polyester nanografts that impart the biodegradability and bioresorbability of polymers with their osteoconductivity, osteoinductivity, and osteointegration properties [ 42 , 43 ].…”

Mg-, Zn-, and Fe-Based Alloys With Antibacterial Properties as Orthopedic Implant Materials

“…However, these permanently implanted alloys still suffer from unresolved drawbacks, including the risk of poisoning and allergies, stress shielding issues, and secondary surgery for implant removal ( Sumner, 2015 ; Seyhan et al, 2018 ). In contrast, biodegradable alloy orthopedic implants have recently been favored by researchers due to their acceptable mechanical properties and in vivo degradability ( Aghion, 2018 ; Yuan et al, 2022 ). Degradable Mg-, Zn-, and Fe-based alloy orthopedic implants with antibacterial properties have also been studied more, which will be described in detail below.…”

“…Besides, a smaller host response ensues ( Aghion, 2018 ). Moreover, the degradation process allows for shifting loads to healing tissues gradually, which resolves the stress shielding issues ( Yuan et al, 2022 ). Furthermore, after full healing of tissues, the complete degradation of alloy materials obviates the need for secondary surgery ( Zheng et al, 2014 ).…”