title: The effect of charged groups on protein interactions with poly(HEMA) hydrogels.
abstract: Proteins, lipids and other biomolecules interact strongly with the acrylic-based biomaterials used for contact lenses. Although hydrogels are nominally resistant to protein fouling, many studies have reported considerable amounts of protein bound to poly(2-hydroxyethylmethacrylate) (PHEMA) lenses. This study examined the binding of a series of biomolecules (tear protein analogues, mucin and cholesterol) to poly(methylmethacrylate) (PMMA) and three HEMA-based hydrogels (PHEMA, HEMA plus methacrylic acid (P(HEMA-MAA)), HEMA plus methacrylic acid plus N-vinylpyrrolidone (P(HEMA-MAA-NVP))) by use of a quartz crystal microbalance with dissipation (QCM-D) monitoring. The QCM-D estimates changes in the mass and viscous constant for the adsorbed layer through measurements of frequency and dissipation. Protein interaction with each of the test materials caused a net increase in mass of the material indicating protein binding except for lysozyme interacting with P(HEMA-MAA). A net decrease in mass was observed for lysozyme interacting with P(HEMA-MAA) which may be ascribed to lysozyme collapsing the hydrogel by expelling water. A net mass decrease was observed for cholesterol interacting with each of the hydrogel materials, while a mass increase was observed on PMMA.
authors.affiliation: Graduate School of Biomedical Engineering, The University of New South Wales, Sydney NSW 2052, Australia. m.lord@student.unsw.edu.au
authors.forename: Megan S
authors.initials: MS
authors.lastname: Lord
authors.forename: Martina H
authors.initials: MH
authors.lastname: Stenzel
authors.forename: Anne
authors.initials: A
authors.lastname: Simmons
authors.forename: Bruce K
authors.initials: BK
authors.lastname: Milthorpe
mesh_terms: D000327:Adsorption; D001665:Binding Sites; D001672:Biocompatible Materials / Q000737:chemistry*; D001798:Blood Proteins / Q000737:chemistry*; D003261:Contact Lenses; D020100:Hydrogels / Q000032:analysis / Q000737:chemistry*; D008422:Materials Testing; D008970:Molecular Weight; D011073:Polyamines / Q000032:analysis / Q000737:chemistry*; D011102:Polyhydroxyethyl Methacrylate / Q000031:analogs & derivatives* / Q000032:analysis / Q000737:chemistry; D011485:Protein Binding; D025941:Protein Interaction Mapping / Q000379:methods*; D055672:Static Electricity; D013499:Surface Properties; D013666:Tears / Q000737:chemistry*
chemical_list: D001672:Biocompatible Materials; D001798:Blood Proteins; D020100:Hydrogels; D011073:Polyamines; C056971:poly(2-hydroxyethyl methacrylate)-polyamine graft copolymer; D011102:Polyhydroxyethyl Methacrylate