A systematic study of enzyme-nanomaterial interactions for application in active surface decontamination

Enzymes are a catalytic class of proteins that possess high specificity, selectivity and biocompatibility, which makes them ideal for multiple applications in industrial production and biotechnology. However, the use of enzymes in such applications is limited due to their low operational stability and increased cost attributed to difficulty of purification and reuse. Immobilization of enzymes onto nano-sized solid supports has emerged as a potential solution to these shortcomings with a trade-off of a percentage of activity loss upon immobilization. Herein, a comprehensive study of enzyme immobilization techniques with emphasis on active-surface decontamination applications is presented.;In Chapter 1, an overview of the potential uses of enzymes and enzyme immobilization techniques is given. Benefits of enzyme-nanosupport conjugates in industrial catalysis, energy production (i.e. biofuels and biofuel cells), biosensing and bioactive coatings are discussed with emphasis on enzyme-based decontamination coatings. It is emphasized that enzyme-based conjugates are capable of increasing enzyme stability at operational conditions used in industrial production of fine chemicals, pharmaceuticals and foods. Also, this Chapter emphasizes the benefits of enzyme immobilization in regard to the development of the next generation of biosensors with enhanced selectivity and specificity or biofuel cells that do not require a membrane, and thus allow miniaturization. Additionally, coatings capable of decontaminating pathogens such as bacteria and spores can be produced through the incorporation of enzymenanomaterial conjugates. Finally, the chapter provides new perspectives and future directions in enzyme-based biotechnology. A. Campbell, C. Dong, C. Xiang, N. Q. Wu and C. Z. Dinu, "Enzyme-Based Technologies: Perspectives and Opportunities" Accepted to Green Polymer Chemistry: Biocatalysis and Biomaterials, ACS Symposium Series 2012..;In Chapter 2, the impacts of the reactions that take place upon enzyme immobilization at the nanointerface are discussed and the effects of multiple variables present in the immobilization process on enzyme retained activity are identified. These variables include nanosupport characteristics (i.e. physical and chemical properties, rate of curvature), enzyme properties (i.e. surface properties, molecular weight, isoelectric point) and immobilization technique (i.e. chemical or physical binding). Prior to immobilization of the selected enzymes (i.e. soybean peroxidase (SBP), chloroperoxidase (CPO) and glucose oxidase (GOX)) all nanosupports (i.e. single-walled carbon nanotubes (SWCNTs), multi-walled carbon nanotubes (MWCNTs) and graphene oxide nanosheets (GON)) are chemically functionalized under user-controlled conditions through strong acids treatment and characterized in terms of structure and morphology. A comparison of how the characteristics of both the nanosupports used as well as immobilization technique employed affect retained activity in an enzyme specific manner is also presented. A. Campbell, C. Dong, J. Hardinger, F. Meng, G. Perhinschi, N. Q. Wu and C. Z. Dinu, "Activity and Kinetics of Immobilized Enzyme Depend on the Enzyme-Interface Reaction" To be submitted to Langmuir..;In Chapter 3, the development of a self-decontaminating enzyme-nanosupport hybrid system is presented. This system is based on the generation of the strong decontaminant hypochlorous acid (HOCl) by CPO. Two strategies are investigated. First, the production of the required substrate (i.e. hydrogen peroxide (H 2O2)) by photocatalytic titanium dioxide nanobelts to be used by immobilized CPO for in situ HOCl generation is tested. Secondly, the production of H2O2 by co-immobilized GOX onto MWCNTs in the presence of glucose to be further used by immobilized CPO for in situ HOCl generation is examined. Characterization of both conjugate systems as well as their capacity for HOCl generation is presented in detail. The decontaminant production capability of the CPO-MWCNTs-GOX system shows promise for the next generation of active surface decontamination coatings. A. Campbell, C. Dong, C. Xiang, N. Q. Wu, J. S. Dordick and C. Z. Dinu, "Bionano Engineering Hybrids for the Next Generation of Self- Sustainable Decontamination Coatings" Submitted to Process Biochemistry..;This thesis also contains Appendices in which supporting information in regard to the respective chapters is detailed. Also attached are other publications in which I have been a contributing author: (1) C. Dong, A. Campbell, R. Eldawud, G. Perhinschi, Y. Rojansakul and C. Z. Dinu, "Effects of Acid Treatment on Structure, Properties and Biocompatibility of Carbon Nanotubes" Applied Surface Science 2013, 264, 261-268. (2) C. Z. Dinu, I. Borkar, S. Bale, A. Campbell, R. Kane and J. S. Dordick "Perhydrolase-nanotube-paint sporicidal composites stabilized by intramolecular crosslinking" Journal of Molecular Catalysis B: Enzymatic 2012, 75,20-2..