In this thesis work, a portable optical biosensor based on surface plasmon resonance imaging was developed and optimized for gas-phase analysis. This system, referred to as high-contrast plasmonic imaging (HC-Pi), enables direct visualization, quantification and real-time multiplex detection of individual microbiological particles. Following the optimization of optical and microfluidic components as well as processing algorithms, the device was characterized using E. coli K12, achieving relevant detection limits within 20 minutes. The approach was then extended to other bacteria (S. pneumoniae) and viruses (Orthopoxvirus), requiring the implementation of alternative bioreceptors such as bacteriophages and hydrolases to complement the use of antibodies. The results successfully demonstrate the ability of the HC-Pi system to detect and quantify infectious bacteria and viruses rapidly, sensitively and in a multiplexed format.​
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