In-vivo study of adhesion and bone growth around implanted laser groove/RGD-functionalized Ti-6Al-4V pins in rabbit femurs

a r t i c l e i n f o Titanium surfaces were designed, produced, and evaluated for levels of osseointegration into the femurs of rabbits. A total of 36 Ti-6Al-4V pins (15 mm length, 1.64 mm diameter) were prepared into three experimental groups. These were designed to test the effects of osseointegration on laser grooved, RGD coated, and polished control surfaces, as well as combined effects. Circumferential laser grooves were introduced onto pin surfaces (40 μm spacing) using a UV laser (λ = 355 nm). The tripeptide sequence, Arginine-Glycine-Aspartic acid (RGD), was functionalized onto laser grooved surfaces. Of the prepared samples, surface morphology and chemistry were analyzed using scanning electron microscopy (SEM) and Immunoflourescence (IF) spectroscopy, respectively. The experimental pin surfaces were surgically implanted into rabbit femurs. The samples were then harvested and evaluated histologically. Sections of the sample were preserved in a methylmethacralate mold, sliced via a hard microtome, and polished systematically. In the case of the RGD coated and laser grooved surfaces, histological results showed accelerated bone growth into the implant, pull-out tests were also used to compare the adhesion between bone and the titanium pins with/without laser textures and/or RGD coatings. The success of an endosseous implant in achieving adequate bone regeneration, stability, and optimal required function is greatly dependent on the nature of the biomaterial and its surface characteristics [1]. One of the most frequently used biocompatible materials is the Ti-6Al-4V [2]. This is due to its excellent combination of biocompatibility, mechanical properties and its inert reactions with tissue once implanted [2,3]. The ability of a biomaterial to support cellular adhesion and spreading is an essential factor reflecting its level of biocompatibility and subsequent osseointegration [1,2]. The key elements for tissue regeneration and integration in the peri-implant area are the recruitment of sufficient osteoprogenitor cells and their differentiation [4]. Surface properties of the implant have proven to play a major role in cellular response and the subsequent tissue healing at the implant interface [1]. This has stimulated prior studies on the influence of surface roughness on cell differentiation, extra cellular matrix synthesis and osseointegration [5]. Furthermore, there are several methods for modifying implant surfaces to promote cellular adhesion [6,7]. These include methods that result in random and uniform surface textures. Alumina blasting is a commonly used process that creates randomized surface textures [2,3,7]. It generally increases the surface area. However, this method can also …