title: Serum protein layers on parylene-C and silicon oxide: effect on cell adhesion.
abstract: Among the range of materials used in bioengineering, parylene-C has been used in combination with silicon oxide and in presence of the serum proteins, in cell patterning. However, the structural properties of adsorbed serum proteins on these substrates still remain elusive. In this study, we use an optical biosensing technique to decipher the properties of fibronectin (Fn) and serum albumin adsorbed on parylene-C and silicon oxide substrates. Our results show the formation of layers with distinct structural and adhesive properties. Thin, dense layers are formed on parylene-C, whereas thicker, more diffuse layers are formed on silicon oxide. These results suggest that Fn acquires a compact structure on parylene-C and a more extended structure on silicon oxide. Nonetheless, parylene-C and silicon oxide substrates coated with Fn host cell populations that exhibit focal adhesion complexes and good cell attachment. Albumin adopts a deformed structure on parylene-C and a globular structure on silicon oxide, and does not support significant cell attachment on either surface. Interestingly, the co-incubation of Fn and albumin at the ratio found in serum, results in the preferential adsorption of albumin on parylene-C and Fn on silicon oxide. This finding is supported by the exclusive formation of focal adhesion complexes in differentiated mouse embryonic stem cells (CGR8), cultured on Fn/albumin coated silicon oxide, but not on parylene-C. The detailed information provided in this study on the distinct properties of layers of serum proteins on substrates such as parylene-C and silicon oxide is highly significant in developing methods for cell patterning.
authors.affiliation: Nanoscience Centre, Department of Engineering, University of Cambridge, Cambridge CB3 0FF, UK; School of Systems Engineering, University of Reading, Reading RG6 6AY, UK.
authors.forename: Evangelos
authors.initials: E
authors.lastname: Delivopoulos
authors.affiliation: Nanoscience Centre, Department of Engineering, University of Cambridge, Cambridge CB3 0FF, UK. Electronic address: mmo25@cam.ac.uk.
authors.forename: Myriam M
authors.initials: MM
authors.lastname: Ouberai
authors.affiliation: School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, UK.
authors.forename: Paul D
authors.initials: PD
authors.lastname: Coffey
authors.affiliation: Farfield, Biolin Scientific, 62 Wellington Road South, Stockport SK1 3SU, Cheshire, UK.
authors.forename: Marcus J
authors.initials: MJ
authors.lastname: Swann
authors.affiliation: School of Pharmacy, University of Nottingham, University Park, Nottingham NG7 2RD, UK.
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Shakesheff
authors.affiliation: Nanoscience Centre, Department of Engineering, University of Cambridge, Cambridge CB3 0FF, UK.
authors.forename: Mark E
authors.initials: ME
authors.lastname: Welland
mesh_terms: D000818:Animals; D002417:Cattle; D002448:Cell Adhesion; D002478:Cells, Cultured; D005353:Fibronectins / Q000737:chemistry*; D051379:Mice; D011108:Polymers / Q000737:chemistry*; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D014992:Xylenes / Q000737:chemistry*
chemical_list: D005353:Fibronectins; D011108:Polymers; D014992:Xylenes; C011055:parylene; D012710:Serum Albumin, Bovine; D012822:Silicon Dioxide
keywords: Biosensing technique; Cell adhesion; Fibronectin; Parylene-C; Serum protein adsorption; Silicon oxide