title: Activity study of self-assembled proteins on nanoscale diblock copolymer templates.
abstract: Novel methods for affixing functional proteins on surfaces with high areal density have the potential to promote basic biological research as well as various bioarray applications. The use of polymeric templates under carefully balanced thermodynamic conditions enables spontaneous, self-assembled protein immobilization on surfaces with spatial control on the nanometer scale. To assess the full potential of such nanometer-scale protein platforms in biosensing applications, we report for the first time the biological activity of proteins on diblock copolymer platforms. We utilized horseradish peroxidase, mushroom tyrosinase, enhanced green fluorescent protein, bovine immunoglobulin G, fluorescein isothiocyanate conjugated anti-bovine IgG, and protein G as model systems in our protein activity studies. When specific catalytic functions of HRP and MT, immobilized on selective domains of microphase-separated PS-b-PMMA, are evaluated over a long period of time, these enzymes retain their catalytic activity and stability for well over 3 months. By performing confocal fluorescence measurements of self-fluorescing proteins and interacting protein/protein systems, we have also demonstrated that the binding behavior of these proteins is unaffected by surface immobilization onto PS-b-PMMA diblock copolymer microdomains. Our polymer platforms provide highly periodic, high-density, functional, stable surface-bound proteins with spatial control on the nanometer scale. Therefore, our diblock copolymer-guided protein assembly method can be extremely beneficial for high-throughput proteomic applications.
authors.affiliation: Department of Chemical Engineering, The Pennsylvania State University, 160 Fenske Laboratory, University Park, Pennsylvania 16802, USA.
authors.forename: Nitin
authors.initials: N
authors.lastname: Kumar
authors.forename: Omkar
authors.initials: O
authors.lastname: Parajuli
authors.forename: Adam
authors.initials: A
authors.lastname: Dorfman
authors.forename: Dylan
authors.initials: D
authors.lastname: Kipp
authors.forename: Jong-in
authors.initials: JI
authors.lastname: Hahm
mesh_terms: D002384:Catalysis; D004800:Enzymes, Immobilized / Q000378:metabolism; D005456:Fluorescent Dyes; D006735:Horseradish Peroxidase / Q000737:chemistry / Q000378:metabolism; D018613:Microscopy, Confocal; D008954:Models, Biological; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D019904:Polymethyl Methacrylate / Q000737:chemistry*; D040081:Protein Array Analysis; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism; D013499:Surface Properties; D013816:Thermodynamics; D013997:Time Factors
chemical_list: D004800:Enzymes, Immobilized; D005456:Fluorescent Dyes; D011506:Proteins; D019904:Polymethyl Methacrylate; D006735:Horseradish Peroxidase