Advances in the surface modification techniques of bone-related implants for last 10 years

Abstract

At the time of implanting bone-related implants into human body, a variety of biological responses to the material surface occur with respect to surface chemistry and physical state. The commonly used biomaterials (e.g. titanium and its alloy, Co-Cr alloy, stainless steel, polyetheretherketone, ultra-high molecular weight polyethylene and various calcium phosphates) have many drawbacks such as lack of biocompatibility and improper mechanical properties. As surface modification is very promising technology to overcome such problems, a variety of surface modification techniques have been being investigated. This review paper covers recent advances in surface modification techniques of bone-related materials including physicochemical coating, radiation grafting, plasma surface engineering, ion beam processing and surface patterning techniques. The contents are organized with different types of techniques to applicable materials, and typical examples are also described.

Keywords: bone-related materials; ion beam processing; physicochemical coating; plasma surface engineering; radiation grafting; surface modification; surface patterning.

Figure 1.

Schematic diagrams of surface modification techniques.

Figure 2.

Schematic diagrams of ion beam surface modification methods (A: IBAD, B: IBSD, C: IBD and D: IBID).

Figure 3.

Cross-sectional micrographs of coatings on various substrates prepared via plasma spray. (A: HA coating on titanium substrate (Reproduced with permission from Ref. [52], Copyright 2007 Elsevier Ltd.), B: 31SiO₂-56CaO-2MgO-11P₂O₅ bioactive glass coating on 316L stainless steel substrate (Reproduced with permission from Ref. [53], Copyright 2013 Elsevier Ltd.), C: HA coating on carbon fibers/polyamide 12 (CF/PA12) composite substrate (Reproduced with permission from Ref. [49], Copyright 2005 John Wiley & Sons, Inc.), D: HA and HA/TiO₂ coating on titanium substrate (Reproduced with permission from Ref. [54], Copyright 2004 Elsevier Ltd.)).

Figure 4.

Chemical covalent bonding processes on different biomaterials. (A: silanization on calcium phosphate bioceramic [59, 60], B: carbodiimide immobilization on titanium metal [61] and C: polypeptide grafting on biopolymer [62]).

Figure 5.

Schematic diagram of ion implantation process.

Figure 6.

Schematic diagram of photolithography procedures.

Figure 7.

Operating steps of µCP and regulation effects of the patterns on cell fate (A: operating steps of µCP, B: regulation effects of the patterns on cell fate by varying aspect ratio [154] (Copyright 2010 National Academy of Sciences), C: regulation effects of different pattern shapes on cell fate [154] (Copyright 2010 National Academy of Sciences)).