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Abstract

The rapid rise of antimicrobial resistance threatens the effectiveness of antibiotics and poses a serious global health risk. Without reliable antimicrobials, many routine medical procedures become unsafe. Bacteriophage–based therapies offer a promising strategy to address this crisis and reduce hospital–acquired infections. However, their widespread implementation is limited by challenges such as identification and scalable production of suitable phages, the emergence of phage resistance, and the lack of standardized protocols and regulatory frameworks. As a simplified, phage–derived alternative, endolysins can directly lyse bacteria, yet they often exhibit limited specificity and are largely restricted to topical applications. In this thesis, I applied bottom–up synthetic biology principles to develop two programmable, virus–inspired antibacterial platforms: synPhages targeting Gram–positive bacteria and synAuPhages targeting Gram–negative bacteria. For Gram–positive bacteria, I engineered minimal synPhages by functionalizing small unilamellar vesicles (SUVs) with bacteriophage receptor–binding proteins (RBPs) for specific bacterial recognition and with endolysins to induce lysis from outside. The developed synPhages mediated faster and more specific bacterial lysis than soluble endolysin alone and enabled strain–selective targeting within mixed bacterial populations through a modular separation of targeting and lytic functions. To address Gram–negative bacteria, I developed synAuPhages by immobilizing phage RBPs on gold nanorods (AuNRs), thereby conferring specific bacterial recognition, while bactericidal activity was achieved via near–infrared–induced photothermal disruption of the heated AuNRs. By relying on targeted physical disruption rather than metabolic inhibition, both platforms are expected to reduce selective pressures that commonly accelerate resistance development. The modularity and effectiveness of synPhages and synAuPhages underscore their potential as antibacterial platforms for diverse applications, including medical flushing solutions, food preservation, and antiseptic strategies for wastewater treatment aimed at multidrug–resistant bacteria.