Endothelial cell growth on silicon modified hydrogenated amorphous carbon thin films

Abstract

The biological response of human microvascular endothelial cells (HMEC-1) seeded on Si-DLC films and on control surfaces was evaluated in terms of initial cell enhancement, growth, and cytotoxicity. The microstructure of the films was characterised by Raman spectroscopy and X-ray photoelectron spectroscopy. The effect of changes in microstructure, surface energy, surface electronic state, and electronic conduction, on the biological response of the films to endothelial cells was investigated. Endothelial cell adhesion and growth was found to be affected by changes in the microstructure of the films induced by silicon doping and thermal annealing. We observed a significant statistical difference in endothelial cell count between the as-deposited DLC and Si-DLC films using the one sample t-test at a p-value of 0.05. We also found a statistically significant difference between the adhesion of HMEC films on DLC and Si-DLC films at various annealing temperatures using the one-way ANOVA F statistic test at p < 0.05 and the post-hoc Tukey test. One sample t-test at p < 0.05 of MTT-assay results showed the endothelial cells to be viable when seeded on DLC/Si-DLC films. We suspect that the increased adhesion of endothelial cells induced by increasing the amount of silicon in the Si-DLC films is associated with the development of a suitable surface energy due to silicon addition, which neither favored cell denaturing nor preferential water spreading before cellular attachment on the film surface. The presence of an external positively charged dipole on the Si-DLC films confirmed by our Kelvin probe measurements is also expected to enhance the adhesion of endothelial cells that are well known to carry a negative charge. The Si-DLC films investigated hold potential promise as coatings for haemocompatible artificial implants.

Characteristic of silicon doped diamond like carbon thin films on surface properties and human serum albumin adsorption

“…This could play a role in the increase of HSA adsorption on the Si-DLC film surface; because a more hydrophobic surface reduces its interaction with water molecules allowing more direct contact with the protein, rather than an interaction mediated by a water layer and this will increase the adsorption layer. These results are in correlation with Ogwu et al, who suggested that increasing the surface hydrophobicity tends to promote human endothelial cell growth and adhesion on the films [46].…”

Improvement of cell attachment capabilities of poly-l-lactic acid films by modification of surface properties with ion-beam irradiation

“…The decrease in cell attachment capabilities at greater amounts of C_C groups is ascribed to the decreased reactivity. The surplus C_C groups and graphitization were reported to reduce cell attachment [18,20,22]. Thus, it may be feasible to control cell attachment and proliferation by adjusting the irradiation appropriately in view of the amount of C_C groups generated.…”

“…Carbon materials comprised of diamond-like carbon (DLC) and amorphous carbons have excellent biocompatibility [16][17][18]. Some studies have reported the impact of chemical bonding states and surface roughness on cell attachment [19,20].…”

In Vitro Study of a Superhydrophilic Thin Film Nitinol Endograft that is Electrostatically Endothelialized in the Catheter Prior to the Endovascular Procedure

“…In the recent years, electrostatic endothelial cell seeding (EECS) has gained attention as an alternative technique to improve the efficiency of cell seeding in terms of number of attached cells and the amount of cell adhesion. In this method, a positive electrostatic charge is temporarily induced on the surface of the graft to promote endothelial cell adhesion [12]. Bowlin et al not only suggested using electrostatic force to seed the endothelial cells inside the small diameter e-PTFE tubes, but also showed acceleration of endothelial cell maturation and cell retention after implant enhancement [13,14,15].…”