Functionalization of titanium surfaces with lysine, aspartic acid, vitamins C and D3: a micro raman study of intermolecular interactions

Abstract

Titanium (Ti) has been used since 1964 in manufacturing of Ti implants because of its optimal mechanical properties and good biocompatibility. Nevertheless, this biomaterial can have failures due to poor osseointegration caused by the spontaneous formation of a passive layer of titanium dioxide (TiO2) when exposed to air. This amorphous TiO2 layer does not promote very well the development of hydroxyapatite (HA) nor the new growing of bone onto the Ti surface implant. The above in conjunction with biological microorganisms lead to malfunction and many times to removal of orthopedic and dental implants based on Ti. Therefore, the compromised patient will be affected in different ways: financially, socially, and psychologically. The work presented describes some processes that can be used to functionalize TiO2/Ti surfaces aimed at to promoting its bioactivity when developing an HA layer on the functionalized Ti surface. The functionalization of Ti surface has been verified by using the Micro Raman Spectroscopy, which provides relevant spectroscopic information that can be used to infer possible intermolecular interactions between adsorbate (biological molecule) and substrate (Ti surface or functionalized Ti surface) leading to bonding. In order to achieve a very good functionalization of Ti surface four target molecules (biomolecules) were used: lysine (Lys), aspartic acid (Asp), ascorbic acid (Vit-C) and cholecalciferol (Vit-D3). They were chosen based on their chemical, physical, and physiological properties conferring to Ti surface the capacity of “in vitro” formation of an HA layer onto it, improving in such way its biocompatibility and durability. Likewise, it will impact directly the bioengineering field because Ti based implants could be manufactured with a better osseointegration and a lower cost than right now, and the patients will be improved their finances regarding the above issue. In summary, the functionalization of Ti surfaces with bioactive molecules and hence biocompatible coatings is a technique that will incidence the clinical success associate to bone-anchored Ti implants, due to the interface stability between Ti implant and bone will be improved.