TITLE:
Study of Human Serum Albumin Adsorption and Conformational Change on DLC and Silicon Doped DLC Using XPS and FTIR Spectroscopy
AUTHORS:
Mukhtar H. Ahmed, John A. Byrne, James McLaughlin, Waqar Ahmed
KEYWORDS:
Diamond Like Carbon; Si-DLC; HAS; Adsorption; XPS; FTIR
JOURNAL NAME:
Journal of Biomaterials and Nanobiotechnology,
Vol.4 No.2,
April
28,
2013
ABSTRACT:
Diamond-like
carbon (DLC) coatings are extremely useful for creating biocompatible surfaces
on medical implants. DLC and silicon doped DLC synthesised on silicon wafer
substrate by using plasma enhanced chemical vapour deposition (PECVD). The effects of surface morphology on the
interaction of HSA with doped and undoped DLC films have been investigated. The
chemical composition of the surface before and after adsorption was analysed
using X-ray photoelectron spectroscopy
(XPS) and Fourier transform infrared (FTIR). Results showed that silicon
incorporation DLC tends to increase of sp3/sp2 hybridization ratio by decreasing sp2 hybridized carbon bonding
configurations. Following exposure to solutions containing (0.250 μg/ml) HSA, the
results indicated that significant changes in the C, N and O levels on the
surfaces with reducing of the Si2p band at 100 eV. From FTIR spectrum, the peaks occur the following functional groups were
assigned as amide I and II groups at 1650
cm-1 and 1580 cm-1. Both XPS and FTIR spectroscopy confirm that HSA was bound onto the surfaces of the DLC and Si-DLC
films via interaction of ionized carboxyl groups and the amino group did not
play a significant role in the adsorption of protein. These results from peak
intensity show that an adsorbed layer of HSA is higher at high level (19%)
silicon doping. Therefore doping of DLC may provide an approach to controlling
the protein adsorption.