AVS 52nd International Symposium
    Biomaterial Interfaces Tuesday Sessions
       Session BI2-TuA

Paper BI2-TuA3
The Generation of Protonated Amine Groups in Plasma Co-Polymers of Acrylic Acid and Allylamine for the Co-Culture of Keratinocytes and Melanocytes

Tuesday, November 1, 2005, 2:40 pm, Room 312

Session: Surface Modification
Presenter: A.J. Beck, University of Sheffield, UK
Authors: A.J. Beck, University of Sheffield, UK
P. Eves, University of Sheffield, UK
J.D. Whittle, Plasso Technology Ltd, UK
N.A. Bullett, Celltran Ltd, UK
S. Mac Neil, University of Sheffield, UK
S.L. McArthur, University of Sheffield, UK
A.G. Shard, University of Sheffield, UK
Correspondent: Click to Email
Plasma polymers prepared from acrylic acid, allylamine and mixtures of the two strongly interacting vapors were characterized using X-ray photoelectron spectroscopy (XPS) and near edge X-ray fine structure (NEXAFS). Plasma polymers prepared from pure acrylic acid and allylamine contained groups retained from the monomer with additional groups formed in the plasma. For the plasma copolymers, the XPS N 1s data and NEXAFS N k-edge provided evidence of protonated amines. The mixture of monomer vapors, in the absence of a plasma, consists of acrylic acid, allylamine and the product of their reaction: allylammonium acrylate salt. More protonated amines were detected in plasma copolymers prepared at low powers suggesting that they were largely retained from the monomer mixture rather than being formed in the plasma. The protonated amines in the monomer mixture undergo less dehydrogenation to nitrile groups in the plasma than the amines from the pure allylamine. This novel use of protecting groups for amines in low power plasmas has the potential to be extended to other desirable groups which tend to be diminished due to fragmentation even in very low power systems. We have demonstrated that plasma co-polymers of acrylic acid and allylamine contain protonated amine groups with carboxylates as the counter anion. It is postulated that such zwitterionic plasma polymers will have interesting surface charge properties in aqueous solution and it may be possible to control the isoelectric point of the surface by varying the plasma conditions and ratio of allylamine to acrylic acid vapors. These surfaces have been shown to facilitate co-culture of keratinocytes and melanocytes.