AVS 53rd International Symposium
    Biomaterial Interfaces Tuesday Sessions
       Session BI-TuA

Paper BI-TuA9
Plasma Polymer Gradients and Their Use for Cellular Guidance

Tuesday, November 14, 2006, 4:40 pm, Room 2001

Session: Cells at Surfaces
Presenter: M.R. Alexander, University of Nottingham, UK
Authors: M. Zelzer, University of Nottingham, UK
R. Majani, University of Nottingham, UK
J.W. Bradley, The University of Liverpool, UK
F.R.A.J. Rose, University of Nottingham, UK
M.C. Davies, University of Nottingham, UK
M.R. Alexander, University of Nottingham, UK
Correspondent: Click to Email
Plasma polymers have recently been shown to be useful in 3D tissue engineering to encourage cell ingress within porous PLA scaffolds and channels intended for applications in bioreactors.@footnote 1,2,3@ To investigate the mechanism of cell ingress we carried out experiments to form surface chemical gradients on planar substrates by diffusion through defined apertures. Consecutive depositions of plasma polymerised allyl amine and hexane on glass has been used to obtain significant variation of water contact angle from 30 to 90 deg, and corresponded to ppHex overlayer thicknesses of of 0 to 10 nm (XPS). AFM was used to identify island deposition on ppAAm at the transition zone from ppHex to ppAAm. This was supported by Tougaard background analysis of the XPS substrate signals which importantly is also applicable to non-planar substrates. It is proposed that the gradual transition may play a role in forming protein adsorption gradients to induce haptotactic cell movement. We present evidence of cellular guidance on such gradients and propose a mechanism based on model protein adsorption studies using quartz crystal microbalance invoking to Vroman effect. This mechanism relies on a ready displacement of albumin by heavier adhesive proteins (e.g. fibronectin) from the hydrophilic ppAAm surface compared with strong albumin adsorption to the hydrophobic ppHex surface. @FootnoteText@ @footnote 1@ Barry, J,et al. Using Plasma Deposits to Promote Cell Population of the Porous Interior of Three-Dimensional Poly(D,L-Lactic Acid) Tissue-Engineering Scaffolds. Advanced Functional Materials 15, 1134-1140 (2005).@footnote 2@ Barry, Jet al. Using a core-sheath distribution of surface chemistry through 3D tissue engineering scaffolds to control cell ingress. Advanced Materials (2006 in press).@footnote 3@ Dehili, C, et al. Comparison of primary rat hepatocyte attachment to collagen and plasma polymerised allylamine on glass. Plasmas Processes and Polymers (2006 in press).