Micro-photonic cylindrical waveguide based protein biosensor

We have experimentally demonstrated the fabrication and the functioning of a rapidly prototyped optical cylindrical microcavity waveguide based biosensor. The device works on the principle of determination of the change to the light intensity of the input coupled light to the waveguide due to the interaction and binding of proteins to the cylindrical waveguide structure. The variation to the coupled light intensity is dependant on the nature of the protein i.e. its surface charge and the density of the proteins. This technique has been used to identify a specific protein biomarker associated with the identification of vulnerable coronary plaque -Myeloperoxidase (MPO). Detection sensitivity in the order of pg/ml has been demonstrated. The detection speed is in the order of seconds from the time of injection of the protein onto the sensor surface. The optical signature that is obtained to identify a protein is entirely dependant on the nature of adsorption of the protein on to the cylindrical cavity surfaces. This technique is a demonstration of detection of nanoscale proteins using a label free optical biosensor technique with unprecedented sensitivity.