Silane coatings of metallic biomaterials for biomedical implants: A preliminary review

Abstract

In response to increased attention in literature, this work provides a qualitative review surrounding the application of silane-based coatings of metallic biomaterials for biomedical implants. Included herein is both a brief summary of existing knowledge and concepts regarding silane-based thin films, along with an analysis of recent peer-reviewed publications and advances towards their practical application for biomedical coatings. Specifically, the review identifies innovative silane-based coatings according to their molecular identity and film structure and analyses their impact on the biocorrosion resistance, protein adsorption, cell viability, and antimicrobial properties of the overall coated implant. It is shown that a range of common silanes clearly exhibit promising properties for biomedical implant coatings, but further work is needed, particularly on mechanisms of physiological interaction and characteristic effects of silane functional groups, before seeing clinical use. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 2901-2918, 2018.

Biological evaluation of preceramic organosilicon polymers for various healthcare and biomedical engineering applications: A review

“…3,4,46 However, the consistency and process accuracy of AM technologies to produce highly complex 3D structures have been metal substrates and silanes. 60 A report has shown reduced corrosion rate with one order of magnitude for a silane-poly (methyl methacrylate) composite coating on a Mg alloy compared to pure silane coating. 61 SEM evaluation of the titanium dioxide/silane coating for corrosion protection of magnesium alloys revealed a coated alloy surface with a significant reduction in cracks and other structural defects.…”

“…This latter feature allows silane to act as a barrier film between the underlying metal implant and the corrosive environment. The adhesion strength and morphology of the silane coatings appear to be influenced by the silane solution conditions and chemical bonding mechanism between metal substrates and silanes 60 …”

Bioactive Coatings on Titanium: A Review on Hydroxylation, Self-Assembled Monolayers (SAMs) and Surface Modification Strategies

“…Once the hydroxyl layer is generated onto Ti surfaces, other strategies such as chemical modifications are carried out in order to obtain extensive options for further functionalization. Among chemical modifications, self-assembled monolayers (SAMs) have been frequently employed due to their high versatility [ 65 , 66 ]. Self-assembled monolayers are generated through the ordered assembly of adsorbed molecular components on the surface of many material and, as a result, a spontaneous thin layer is created [ 67 , 68 , 69 ].…”

The Effect of the Corrosion Medium on Silane Coatings Deposited on Titanium Grade 2 and Titanium Alloy Ti13Nb13Zr

“…In medical applications, titanium alloys containing chiefly elements that are nontoxic and with no allergenic effect, such as niobium, zirconium, tantalum, molybdenum or tin, are being used more and more often [ 6 , 10 ]. Among the main problems involved with the use of metallic materials in implantology, the insufficient corrosion resistance of metals and their alloys is primarily indicated [ 13 , 14 , 15 ]. The common methods employed in corrosion protection include silanization—a modification of the surface with a silane-based solution [ 16 , 17 ].…”

“…Silanes are most commonly used as either coupling agents or crosslinkers [ 18 ]. The bonding between the organic silane agent and the inorganic substrate involves the following steps: (i) hydrolysis of the oxide groups of the metallic substrate and the silane coating to form metal hydroxide and silanol; (ii) formation of a hydrogen bond between the metal and silane hydroxyl groups; (iii) condensation of the bonded hydroxyl groups on the substrate and coating surfaces—a Si-O-Me covalent bond is created and the water molecule is released; (iv) condensation of the silane hydroxyl groups—a Si-O-Si siloxane bond is formed and the water molecule is released [ 13 , 19 ]. Among the methods used for depositing coatings on metallic surfaces, electrochemical, chemical and sol–gel methods are distinguished [ 20 ].…”