Genetically Engineered Solid Binding Peptides (GEPI) for Surface Biofunctionalization Applications: Immobilization of Enzymes and Antimicrobial Peptides on Solids
Yucesoy, Deniz Tanil
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Biological activation and functionalization of solid material interfaces by functional integration of biomolecules is emerging as one of the most dynamic fields of research, impacting a diverse array of applications. Recent advances in translating the biomolecular mechanisms into the hybrid materials and systems design promise novel methodologies that may transform some of our engineering approaches. One of the key issues on design of such systems is the integration of bioactive molecules at the material interfaces without compromising their spatial distribution, surface organization and orientation-dependent bioactivity within a desired proximity. Here, we propose to demonstrate the effective utilization of specific solid binding peptides as anchoring molecules that can be further functionalized to create chimeric peptides. These chimeric molecules are engineered to have built-in solid binding surface binding property in addition to displayed biological functionality as shown by two different case studies. In case study I, we take the initial steps toward designing multifunctional, enzyme-based platforms by genetically integrating the engineered solid binding peptide tags for tethering redox enzymes onto electrode surfaces. Specifically, utilizing the gold binding peptide (AuBP2) as a molecular erector, we engineered a fusion protein that genetically conjugates to the formate dehydrogenase (FDH) enzyme. Following the binding kinetics and catalytic activity analysis of fusion protein, we created a circuit-based biosensor system and demonstrated the effectiveness of the fusion FDH enzyme electrode over multiple cycles by addition of formate as the substrate. In case study IIA and IIB, the capability of GEPI's on biomolecular surface functionalization was demonstrated. Here, titanium alloy and zirconium implant surfaces were coated with implant binding peptides which were conjugated to another peptide domain which was engineered with antimicrobial property, resulting a chimeric peptide compromising both solid binding (GEPI's) and antimicrobial (AMP) properties. The efficiency of chimeric/bifunctional peptides both in solution and on titanium surface was evaluated in vitro against common oral and orthopedic infectious organisms, S. mutans and S. epidermidis, respectively and a control organism E. coli. Our findings demonstrate the successful utilization of solid binding peptides as anchoring molecules to design engineered peptide-mediated self-integrated electrode systems and medical devices. The molecular recognition based self-organization of solid binding peptides can be extended to develop a wide range of application where they can be part of biosensing, energy harvesting, biomedical platforms build upon their utilization as biological building blocks combining different combinations of solid materials to large repertoire of biomolecules.