In today's society, there is a constant growing need to protect people from exposure to pathogen threats that affect health and wellbeing. Current decontamination methods are performed after exposure has occurred, and typically employ bleach, incineration, photocatalysis, or formaldehyde gas. All are time consuming, require significant resources and personnel, are environmentally unfriendly and highly corrosive, and require significant dosages to be effective. Thus, there is a critical need to develop measures that can successfully address contamination rapidly, completely, and in an economical manner. PIs Dinu and Wu of the Chemical Engineering Department at West Virginia University propose to develop self-sustainable and self-decontaminating coatings which are based on biocatalysts of chloroperoxidase (CPO) enzyme and the photocatalyst titanium dioxide, which are capable of decontaminating a large variety of pathogens, including spores of B. cereus (a model for B. anthracis). The biomimetic approach capitalizes upon the attachment of CPO to titanium dioxide nanomaterials, and in situ generation of reactive species of hydrogen peroxide by photocatalysis on the titanium oxide. The peroxide is used by the CPO enzyme as substrate for the local formation of hypochlorous acid, which is the decontaminant. This biomimetic approach would detoxify many times the biocatalyst weight thus reducing the logistical burdens of delivering large amounts of chemicals and eliminating environmental damage. Moreover, the proposed research is a potential platform as its successful completion would lay the foundation for future application of biocatalytic-based decontamination to a variety of chemical and biological agents by using a cocktail of enzyme with different specificities.
The broader implications have already been recognized. Attention has been given to attempts to design environmentally friendly coatings that are capable of decontaminating a large variety of biological agents including spores, rapidly and completely, in an economical manner and without imposing an undue logistical burden for widespread deployment. Dinu and Wu propose to use nanomaterials of titanium dioxide for in situ generation of hydrogen peroxide. The enzyme-nanomaterials conjugates could then be incorporated into paint and generate coatings capable of decontaminating any species that adsorbs on the surface. The proposed research is significant because its successful completion will lead to fundamental knowledge about structure-affinity, structure-stability, and structure-function relationships for enzyme-nanomaterial conjugates. Understanding how the enzyme scaffolding can be stabilized by covalent or non-covalent association with nanomaterials such as titanium dioxide will in turn lead to understanding the platform for electron transfer and the decontamination pathways. Such a platform can be further engineered by modification of the nanomaterial or of the enzyme to tune the electron transfer properties and allow user-control of the biocatalytic-based decontamination. The project offers potential in education as well. The inherent interdisciplinary nature of the proposed research offers tremendous opportunities for enticing and integrating students with educational experience across diverse areas including biology, biochemistry, physics, chemistry and materials science. As the project involves aspects of life that are of interest and concern to people in many walks of life, and can be communicated in easily understood terms, the outreach and public education potential is very large.
Recognition of immediate toxicity of biological agents is a critical need when detection and remediation is considered. Through our research we have aimed to develop „self-sustainable" systems based on biocatalysts and capable of decontaminating biological agents; the biomimetic approach that we developed involved immobilization of enzymes at nanointerfaces and generation of active species to detoxify bacteria present in an environment. Through our work we have shown that biocatalysts immobilization onto nanosupports can lead to increased enzyme stability and allow for enzyme retention and recovery not only for our specific application in decontamination, but also for applications ranging from biosensing to biotransformation, and energy storage. For instance, through the comprehensive and systematic methods that we developed, we revealed that understanding and controling/ manipulating the interplay reactions that take place upon immobilization of model enzymes (e.g., enzymes with different surface energies, molecular weights) onto nanosupports with different physico-chemical properties (i.e., surface chemistry, charge and aspect ratios) could determine the enzyme catalytic behavior as well as its retained activity at the nanosupports interface. Further, we have shown that the optimum design and control of the bio-nano interfaces will allow increased catalytic efficiency and thus is crucial for the fabrication of the next generation of bio-nano conjugates with intended technological and industrial usages. Knowledge gained from our studies can be used to optimize enzyme-nanosupport symbiotic reactions and provide user-based feedback in order to maintain optimal levels of enzyme activity. Further, the knowledge gained from our studies is required for improved interfacial interactions and formation of stable catalytic interfaces, with the greater understanding of the molecular requirements and symbiotic reactions at such interfaces being needed for integrated technological applications of bio-nano conjugates in industry, biosensors, biofuel cells and bioactive coatings for decontamination. The inherent interdisciplinary nature of our research offered tremendous opportunities for enticing and integrating students with educational experience across diverse areas (i.e. biology, biochemistry, physics, chemistry, chemical engineering and materials science). Public presentations and summary reports that presented the fundamental findings in non-technical terms were posted on the websites, formatted as press releases for the local news media, or were integrated during parents and students high school visitation days and other outreach programs to highlight the application of biocatalysis-based decontamination and thus to contribute to public education and outreach.
