Detection of bacteria for public health and consumer protection presents a major challenge, with most microbiological laboratory tests taking days to complete and requiring skilled operation, such that new techniques for rapid screening or high sensitivity detection are urgently needed. The goal of this project will be to investigate the use of inline optical analysis in a microfluidic device as a means to detect and identify bacteria-like nanoparticles potentially allowing a test to be carried out in a greatly reduced time using a push-button or automated device. Making use of the fact that several important bacteria such as listeria and legionella are rod-shaped particles of order a few hundred nanometres in width by 1-3 micrometres in length, the project will utilise optical microresonators in which particle size, aspect ratio, and refractive index can be measured to provide a powerful fingerprint for the identification of particles. It will involve adapting existing apparatus to include shape analysis, and the systematic study of test samples to establish instrument specifications. The project will be carried out in close communication with Oxford HighQ Ltd, a new spin-out from the group which is developing commercial instrumentation for nanoparticle analysis..