Bacterial meningitis caused by Neisseria meningitidis is responsible for considerable morbidity and mortality. This book describes the approaches towards the development of gold nanoparticle-based tests for the rapid detection of N. meningitidis infection. A highly selective quartz crystal microbalance (QCM)-based immunosensor was designed using the OMP85 Ag and anti-OMP85 Ab system as a model to test the infection. A self-assembled monolayer model was developed using PVDF coated QCM crystals with protein A for the directional orientation of the antibodies. The resonant frequency of the sensor as a measure of sensitivity was further enhanced by gold nanoparticles, as signal amplification probes. Also, this sensor was able to detect whole cell bacteria at a concentration as low as 100 cfu/mL. Thus, in this study using the real-time QCM measurements, a novel strategy has been developed for the sensitive detection of both N. meningitidis bacteria and the protein antigen at very low concentrations, using gold nanoparticles as signal amplification probes. This work advances the design and evaluation of a QCM based model biosensor for the rapid diagnosis of meningococcal infection.