New Tools for Diagnosis and Treatment of Bacterial Infections

The excessive and inappropriate use of antibiotics has contributed to the spread of antibiotic resistance, a serious challenge the global health industry is facing. To help preserve the effectiveness of current commercially available therapies, timely, accurate and user-friendly diagnostic tools are needed; advances in biosensing and microfluidics aim to address these limitations in conventional testing. With improvements in diagnostic testing comes the ability to administer personalized patient treatments, an area which has become increasingly explored. In wound care applications, for example, different wound types may display impairments in various phases of the healing process, requiring distinct therapeutics to improve patient outcomes. This thesis first explores the development of a diagnostic device for the rapid detection of methicillin- resistant Staphylococcus aureus, the most common cause of hospital- and community-acquired bacterial infections. The approach relies on nanoparticle-mediated microfluidic capture and electrochemical detection of clinically relevant concentrations of bacteria directly from patient nasal swab specimens. Next, an integrated and automated digital microfluidics platform was designed for simultaneous real-time antibiotic susceptibility testing and bacterial identification via fluorescence detection. This versatile all-in-one instrument with a small footprint allows automation of assay steps for simple sample handling, which can be easily customized for the desired application, without device redesign. Finally, multifunctional hydrogel wound dressings with programmable spatiotemporal release of biologically active agents, including small molecule antibiotics, growth factors and antibacterial silver, were investigated in vivo for personalized wound healing. The biocompatible wound dressings were fabricated via 3D printing, for simple fabrication that could be tailored to patient needs. Altogether, these studies present novel tools to better diagnose bacterial infections and treat wound patients through personalized medicine.