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ABSTRACT: Current methods used for the detection of residual proteinaceous contamination vary in sensitivity and specificity. This is of concern because it increases the risk for transmission of neurodegenerative diseases such as spongiform encephalopathies.
To determine the effectiveness of electrolysis-assisted sonication (EAS) for removing residual proteinaceous contamination from surgical grade stainless steel.
EAS was used to clean surgical grade 316L stainless steel that had been contaminated with the protein bovine serum albumin. Using nitrogen, an abundant element in proteins, as a marker for the presence of protein, X-ray photoelectron spectroscopy (XPS) was used to quantify the amount of protein remaining on the substrate surface. Cathodic, anodic and dual polarization modes of EAS were investigated using 0.1% NaCl solution (w/v, in deionized water) as the electrolyte medium and 13 V as the polarization voltage.
EAS under dual polarization was found to be the most effective method for removing the residual protein layer down to an estimated XPS detection limit of 10 ng/cm(2). Surface roughness and hardness of the stainless steel remained unchanged following EAS treatment, indicating that the procedure does not compromise the material's properties.
This relatively inexpensive and quick method of cleaning medical devices using an easily accessible salt-based electrolyte solution may offer a cost-effective strategy for cleaning medical and dental devices made of stainless steel in the future.
The Journal of hospital infection 03/2012; 81(1):41-9. · 3.01 Impact Factor
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Applied Surface Science 05/2009; 255:6846-6850. · 2.10 Impact Factor
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Applied Surface Science. 255(15):6846-6850.
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Surface and Coatings Technology. 205(5):1630-1635.
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ABSTRACT: Osseointegration is a complex process governed by the interaction of many cell types including blood cells (erythrocytes, platelets and leukocytes), phagocytic cells (macrophages) and bone cells (osteoblasts and osteoclasts) on or near the implant surface. The implant surface can be modified through a variety of methods in order to achieve control of some of these cellular interactions and consequently increase the degree of implant fixation with the surrounding bone tissue. In this investigation, titanium was coated with hydroxylated silica by plasma enhanced chemical vapour deposition (PECVD) to increase the surface hydrophilicity and generate reactive surface silanol groups. Subsequently, the silica-coated titanium surface was further modified through silanisation to generate surfaces bearing different reactive chemical functionalities consisting of aldehydes, epoxides and isocyanates, which can react with the amino groups of proteins and growth factors. 2,2,2-trifluoroethylamine (FEAM) was reacted on these surfaces to determine the coupling efficiency of the different surface chemical functionalities. The amino group of FEAM can react with an amino-reactive surface functional group to form a surface terminated with 3 fluorine atoms per FEAM molecule that can be detected by X-ray photoelectron spectroscopy. By analysing the techniques used for protein attachment with the FEAM model molecule, a successful method for isocyanate/amine coupling was found and later adapted for tethering IGF-1 molecules to the functionalised PECVD silica-coated titanium surface. Therefore, this simple method of preliminary testing protein reactivity may prove to be a cost effective strategy in the development of new biomaterial surfaces modified using protein bioconjugation methods. © 2010.
Surface and Coatings Technology. 205(5):1630-1635.
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ABSTRACT: This report describes the amino functionalisation of the surface of plasma enhanced chemically vapour deposited silica films (PECVD-SiO2), which were coated onto titanium substrates. Amino groups were linked to PECVD-SiO2 via 3-aminpropyl triethoxysilane (APTES). We showed that the APTES functionalised PECVD-SiO2 surfaces contained a high packing density of amino groups (67-92 NH2 groups per nm2), indicative of a multilayered and highly cross-linked APTES film. 65-66% of the original surface concentration of APTES was retained on the PECVD-SiO2 surface after incubation under physiological conditions, indicating that APTES films are relatively stable on PECVD-SiO2 in these environments. The stability of the amino groups obtained on PECVD-SiO2 in this study is much higher compared to other hydroxyl-bearing materials, such as titanium. Therefore, PECVD-SiO2 films may find use as functional biomaterial coatings and as intermediate adhesion layers in silanisation processes. © 2009 Elsevier B.V. All rights reserved.
Applied Surface Science. 255(15):6846-6850.
