Biomedical Alloys and Physical Surface Modifications: A Mini-Review

Abstract

Biomedical alloys are essential parts of modern biomedical applications. However, they cannot satisfy the increasing requirements for large-scale production owing to the degradation of metals. Physical surface modification could be an effective way to enhance their biofunctionality. The main goal of this review is to emphasize the importance of the physical surface modification of biomedical alloys. In this review, we compare the properties of several common biomedical alloys, including stainless steel, Co-Cr, and Ti alloys. Then, we introduce the principle and applications of some popular physical surface modifications, such as thermal spraying, glow discharge plasma, ion implantation, ultrasonic nanocrystal surface modification, and physical vapor deposition. The importance of physical surface modifications in improving the biofunctionality of biomedical alloys is revealed. Future studies could focus on the development of novel coating materials and the integration of various approaches.

Keywords: biomedical alloys; mechanical biocompatibility; surface modifications.

Figure 1

(a) Poly(lactic-co-glycolic acid)-based bone-substitute materials for bone repairing and healing. (b) Biomedical application of Mg-based biomaterials and their corresponding physiological processes. (c) The fabrication and role of biomaterials in the delivery of cells, bioactive molecules, growth factors, and drugs for tissue engineering applications. (Reproduced with permission from [3,14,15]. Copyright (2021), Elsevier.)

Figure 2

Comparison of strength, ductility, corrosion, and wear resistance as well as biocompatibility of stainless steel (red), Co–Cr (blue), and Ti (green) alloys.

Figure 3

Commonly used methods to modify surfaces of biomedical alloys.

Figure 4

Schematics showing the ultrasonic nanocrystal surface modification process.