In vitro Biocompatibility Analyses of Stents Coated with Diamond-Like Carbon by Flow Cytometry, Cell Growth Assays and Electron Microscopy

Abstract

Background: Coronary artery stents can induce platelet activation by shear forces and contact to the biomaterial. This activation is one important trigger for thrombosis. Coating of stents is a possible approach to prevent this side effect. The purpose of this study was to evaluate in vitro the biocompatibility of stents coated with diamond-like carbon (DLC). Materials and Methods: For in vitro testing, DLC-coated stents were compared with noncoated 316L stainless steel stents. For this purpose, cell culture assays, videomorphometric, electron microscopic and flow-cytometric techniques were applied. Results: Growth assays with smooth muscle cells and endothelial cells revealed that DLC did not affect proliferation rates and did not have cytotoxic effects. Video-based morphometry and scanning electron microscopy showed an ultrasmooth surface and homogenous expansion patterns of the DLC stents. For analysis of platelet antigens in a circulating loop model, flow cytometry was applied. Our experiments showed no significant changes in mean channel fluorescence intensity for the structural antigens CD41a (p = 0.6) and CD42b (p = 0.1). In contrast, the expression of the activation-dependent antigens CD62p and CD63 increased significantly in noncoated stents compared to DLC-coated stents (p < 0.05). Conclusion: Coating of intracoronary stents with DLC significantly reduces platelet activation. Hereby, biocompatibility is improved.

Biological Characteristics of the MG-63 Human Osteosarcoma Cells on Composite Tantalum Carbide/Amorphous Carbon Films

“…The biological effect of a-C coatings on various metal or polymer substrates exhibited good biocompatibility and haemocompatibility in different lineages of cells. The proliferation rates of smooth muscle and endothelial cells cultured onto a-C-coated stents were neither affected nor reduced [23]. The surface roughness of a-C increased the cell adhesion and proliferation of human fibroblasts [35].…”

“…A recent study showed that a-C coating on artificial hip joints reduced the wear debris [20]. Several in vitro studies have also demonstrated that a-C coatings improved the adhesion and growth of osteoblasts, reduced platelet attachment, and inhibited activation [22], [23].…”

Mechanical Properties and Biocompatibility of Ti-doped Diamond-like Carbon Films

“…The bioinertness of DLC has been confirmed in various studies. 7 − 12 For example, studies on the effects of DLC coatings on cells found no evidence of cytotoxicity, 12 and studies of the interactions of macrophages with DLC coatings have confirmed that DLC does not induce inflammatory reactions in cells. DLC has also shown excellent biocompatibility with blood monocytes; 9 this is crucial because monocytes control inflammatory reactions that can affect osteointegration of implants.…”

Human Umbilical Vein Endothelial Cell Interaction with Fluorine-Incorporated Amorphous Carbon Films

“…16) Chu et al shown better adhesion and high viability of ECs on a-C:H coated surface comparing with conventional stent materials of nickel titanium (Ni-Ti).…”

“…initially revealed that the a-C:H coatings improve the hemocompatibility of conventional stainless steel stents without suppression of compatibility for ECs in a comparative experiment using stainless steel stents and a-C:H coated stents in vitro. 16) Chu et al shown better adhesion and high viability of ECs on a-C:H coated surface comparing with conventional stent materials of nickel titanium (Ni-Ti). 17) The compatibility of various atomics incorporated in a-C:H films with endothelial cells has also been studied.…”