POF based glucose sensor incorporating grating wavelength filters

Medtronic has already developed a plastic fiber based optical sensor to detect the concentration of glucose both in vivo and in-vitro. The glucose sensor is based on a competitive glucose binding affinity assay consisting of a glucose receptor and glucose analog (ligand) contained in a compartment made up of permeable membrane for exchanging of only small molecules such as glucose, salts etc. (Fig 1). The binding between the glucose binding protein labeled with flourophore and glucose like molecules labelled with dye, is reversible. In the presence of glucose, the glucose analog competes with the glucose on binding to the protein. The system reaches an equilibrium, which correlates with the glucose concentration.The assay chemistry makes donor and acceptor pair for FRET (Förster Resonance Energy Transfer). FRET results in decrease in donor emission intensity. Higher the concentration of glucose, more donor acceptor pairs got separated resulting in high intensity and vice versa. This change in optical signal is correlated to glucose concentration. (Fig.1) Medtronic Diabetes and DTU FOTONIK has been working together under the consortium of Marie Curie Research Framework called TRAINING AND RESEARCH IN POLYMER OPTICAL DEVICES; TRIPOD. Within the domain of TRIPOD, research is conducted on "Plastic Optical Fiber based Glucose Sensors Incorporating Grating Wavelength Filters". Research will be focused to optimized fiber tips for better coupling efficiency, reducing the response time of sensor, improve the mechanical stabilization of assay compartment by exploring the side excitation and side coupling method, ease of manufacturing and feasibility of Polymer Fiber Bragg gratings as filters. During the project, fibers will be drawn and fiber bragg gratings will be inscribed at DTU Fotonik and they will be characterized for glucose sensor at Medtronic Diabetes.