Optical Bio-Sensing Probe

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BACKGROUND This technology is capable of detecting proteins, viruses, and bacteria for a large range of applications depending on the surface functionalisation (antibodies) in various clinical samples, including undiluted serum without non-specific binding which often results in false positive results. The technology is uniquely positioned as a label free sensing platform exhibiting similar capabilities (real time kinetic measurement, quantification and determination of binding constants) compared to more well-known and commercially viable technologies such as Surface Plasmon Resonance as measurements can be performed either in-vitro or in-vivo. TECHNOLOGY This unique label free bio-sensing platform technology relies on combining the refractive index sensing capability of Whispering Gallery Modes in dye doped spherical micro resonators, with the light-guiding properties of micro structured optical fibres. The fibre provides a pathway for remote exiting and collection of the Whispering Gallery Modes signal produced by single or multiple microspheres simultaneously, positioned onto one end of the fibre. The specific architecture of the fibre also enables the microsphere to be held in position, anchoring it into one of the fibre holes, running along the entire fibre length. More importantly, this permits easy manipulation and positioning of the microsphere where sensing needs to be done. The sensing mechanism is based on exploiting the sensitivity of Whispering Gallery Modes toward changes of refractive index at the surface of the dye doped microsphere. Appropriate surface functionalisation of the microsphere surface ensures that only the desired target analyte can bind to the microsphere surface, which in turn produces a wavelength shift of the resonance features proportional to the amount of bound analyte - enabling not only detection but also quantification. The approach of using dye doped microspheres allows exploiting lasing of the Whispering Gallery Modes which improves the resolution of the sensing platform and enables better performance. The use of multiple microspheres with different surface chemistry allows for either compensation for change of local environments, including non-specific binding in real clinical samples, or for the simultaneous detection of multiple analytes.