title: Design and implementation of two-dimensional polymer adsorption models: evaluating the stability of Candida antarctica lipase B/solid-support interfaces by QCM-D.
abstract: A two-dimensional model of a solid-supported enzyme catalyst bead is fabricated on a quartz crystal microbalance with dissipation monitoring (QCM-D) sensor to measure in situ interfacial stability and mechanical properties of  Candida antarctica  Lipase B (CAL B) under varied conditions relating to ring-opening polymerization. The model was fabricated using a dual photochemical approach, where poly(methyl methacrylate) (PMMA) thin films were cross-linked by a photoactive benzophenone monolayer and blended cross-linking agent. This process produces two-dimensional, homogeneous, rigid PMMA layers, which mimic commercial acrylic resins in a QCM-D experiment. Adsorption of CAL B to PMMA in QCM-D under varied buffer ionic strengths produces a viscoelastic enzyme surface that becomes more rigid as ionic strength increases. The rigid CAL B/PMMA interface demonstrates up to 20% desorption of enzyme with increasing trace water content. Increased polycaprolactone (PCL) binding at the enzyme surface was also observed, indicating greater PCL affinity for a more hydrated enzyme surface. The enzyme layer destabilized with increasing temperature, yielding near complete reversible catalyst desorption in the model.
authors.affiliation: Materials Science & Engineering Division, National Institute of Standards and Technology , Gaithersburg, MD 20899, United States.
authors.forename: Sara V
authors.initials: SV
authors.lastname: Orski
authors.forename: Santanu
authors.initials: S
authors.lastname: Kundu
authors.forename: Richard
authors.initials: R
authors.lastname: Gross
authors.forename: Kathryn L
authors.initials: KL
authors.lastname: Beers
mesh_terms: D000327:Adsorption; D055162:Biocatalysis; D002175:Candida / Q000201:enzymology; D004795:Enzyme Stability; D004800:Enzymes, Immobilized; D005656:Fungal Proteins / Q000737:chemistry* / Q000378:metabolism*; D008049:Lipase / Q000737:chemistry* / Q000378:metabolism*; D009994:Osmolar Concentration; D011091:Polyesters / Q000378:metabolism; D011108:Polymers / Q000737:chemistry; D019904:Polymethyl Methacrylate / Q000737:chemistry / Q000378:metabolism*; D058525:Quartz Crystal Microbalance Techniques; D013499:Surface Properties; D055682:Viscoelastic Substances; D014867:Water / Q000737:chemistry
chemical_list: D004800:Enzymes, Immobilized; D005656:Fungal Proteins; D011091:Polyesters; D011108:Polymers; D055682:Viscoelastic Substances; D014867:Water; C016240:polycaprolactone; D019904:Polymethyl Methacrylate; D008049:Lipase; C431349:lipase B, Candida antarctica