Adhesion, activation, and aggregation of blood platelets and biofilm formation on the surfaces of titanium alloys Ti6Al4V and Ti6Al7Nb

Abstract

Titanium alloys are still on the top list of fundamental materials intended for dental, orthopedics, neurological, and cardiovascular implantations. Recently, a special attention has been paid to vanadium-free titanium alloy, Ti6Al7Nb, that seems to represent higher biocompatibility than traditional Ti6Al4V alloy. Surprisingly, these data are not thoroughly elaborated in the literature; particularly there is a lack of comparative experiments conducted simultaneously and at the same conditions. Our study fills these shortcomings in the field of blood contact and microbiological colonization. To observe platelets adhesion and biofilm formation on the surfaces of compared titanium alloys, fluorescence microscope Olympus GX71 and scanning electron microscope HITACHI S-3000N were used. Additionally, flow cytometry analysis of platelets aggregation and activation in the whole blood after contact with sample surface, as an essential tool for biomaterial thrombocompatibility assessment, was proposed. As a result of our study it was demonstrated that polished surfaces of Ti6Al7Nb and Ti6Al4V alloys after contact with whole citrated blood and E. coli bacterial cells exhibit a considerable difference. Overall, it was established that Ti6Al4V has distinct tendency to higher thrombogenicity, more excessive bacterial biofilm formation and notable cytotoxic properties in comparison to Ti6Al7Nb. However, we suggest these studies should be extended for other types of cells and biological objects.

Differences in the expression of cell cycle genes in osteoblasts and endothelial cells cultured on the surfaces of Ti6Al4V and Ti6Al7Nb alloys

“…One example of such a search is an attempt to replace commonly used in medicine Ti6Al4V alloy by Ti6Al7Nb alloy. The latter has better corrosion resistance and does not release toxic vanadium, and is also assigned to other positive traits …”

“…The latter has better corrosion resistance [4][5][6][7] and does not release toxic vanadium, and is also assigned to other positive traits. [12][13][14] The literature delivers different and often contradictory information on cells' proliferation on the surfaces of these alloys. The article 15 shows that the oxidized and nonoxidized surfaces of both alloys in different manner affected proliferation of osteoblast-line Saos-2.…”

“…Therefore, molecular biology techniques have become more and more popular in the field of biomaterials engineering, allowing to predict and control the mechanisms of cell-implant interaction more effectively and, consequently, to evaluate the biocompatibility of materials intended for implantation more fully. [8][9][10][11] Our earlier report 12 was focused on comparison of thrombo-compatibility and susceptibility to bacterial colonization of Ti6Al4V and Ti6Al7Nb alloys, and we found that niobium containing alloy is slightly less thrombogenic and more resistant to bacterial colonization, whereas vanadium containing alloy is significantly more cytotoxic. Continuing our interest in biological evaluation of both titanium alloys we have decided to enter molecular level of cell response to contact with biomaterial surface and to track differences in the expression of genes regulating cell cycle in the cells cultured on the titanium alloys' surfaces.…”

Real time visualization and characterization of platelet deposition under flow onto clinically relevant opaque surfaces

“…The manufacturers of the Heartmate‐II and other continuous flow VADs currently use a polished titanium alloy (Ti6Al4V) as the blood contacting surface due to its desirable mechanical properties, resistance to corrosion, and tolerable blood compatibility . However, in vitro studies have shown that this alloy exhibited elevated acute thrombogenicity compared to other coated surfaces (e.g., polyethylene glycol and diamond‐like coatings) or related alloys (Ti6Al7Nb) . This study was therefore conducted to perform a systematic side‐by‐side comparison of six candidate biomaterials currently being considered for application in continuous‐flow blood pumps.…”

“…11 However, in vitro studies have shown that this alloy exhibited elevated acute thrombogenicity compared to other coated surfaces (e.g., polyethylene glycol and diamond-like coatings) or related alloys (Ti6Al7Nb). 2,5,12,13 This study was therefore conducted to perform a systematic side-by-side comparison of six candidate biomaterials currently being considered for application in continuous-flow blood pumps. However, since these materials are opaque, traditional methods for real time visualization of platelet deposition, such as fluorescent microscopy utilizing whole blood, are not readily applicable.…”