2008 NSTI Nanotechnology Conference and Trade Show - Nanotech 2008 - 11th Annual

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Clean Technology 2008

Influence of water contact angle on cell adhesion on polystyrene surfaces

M. Ardhaoui, M. Nassiri, M. Rubaei, D. Dowling
Post Doctoral Researcher, IE

Keywords:
cell adhesion, contact angle, surface modification

Abstract:
In this study, the effects of water contact angle on adhesion strength and cell viability of various mammalian cell types on polystyrene were studied. Different contact angles were obtained by varying the chemistry of siloxane (SiOx) coatings. Nanometer thick coatings were deposited using an atmospheric pressure plasma from a liquid poly(dimethylsiloxane) precursor. The precursor was nebulised into helium or helium/oxygen plasma. By altering the exposure duration of the precursor to the plasma, the coating chemistry was systematically altered and thus water contact angles in the range 20 to 97° were obtained. Coatings deposited at higher levels of plasma exposure exhibited more hydrophilic properties, while those deposited with decreased plasma exposure and in the absence of oxygen were more hydrophobic. Fourier Transform Infrared Spectroscopy and X-ray Photoelectron Spectroscopy demonstrated that these changes were associated with an increase in the SiOx content within the coating, with higher plasma exposure. Optical profilometry was used to monitor changes in surface roughness (Ra) with changes in the deposition parameters. Typical Ra values were approximately 20 nm. The cells adhesion strength and viability were determined for the following cell types: Human Embryonic Kidney (HEK), chondrocytes, Chinese hamster ovary (CHO) and hepatocytes (HepZ). Cells were allowed to adhere and grow for 20 hours at 37 ºC in treated polystyrene dishes. The study demonstrated that adhesion strength is cell type and surface dependent. Chondrocytes and HEK cells adhered better on moderately hydrophilic surfaces. In contrast, CHO and HepZ cells were found more adhesive on hydrophobic polystyrene surface. Hydrophilic surfaces did not affect cell viability, but low cell viability was observed on hydrophobic surfaces. The HepZ viability was higher on moderately hydrophilic polystyrene surface (80%) in comparison to hydrophobic surface. These results demonstrate the importance of the biomaterial surface wettability on cell attachment and confirm the major and complex role of the proteins-surface interaction in determining cell adhesion. The results are significant for the assessment and design of new surfaces for biological applications.


Nanotech 2008 Conference Program Abstract