Glucose oxidase immobilized PANI cladding modified fiber optic intrinsic biosensor for detection of glucose

• PANI cladding modified FOIGB has been developed for glucose sensing.
• PANI film was characterized by UV–vis, XRD, FT-IR, FE-SEM and optical imaging.
• Enzyme-GOx was immobilized on sensing element via cross-linking.
• Power and MPD have been utilized to measure glucose concentration and stability.
• FOIGB is highly selective toward glucose and has lowest detection limit of 10 nM.

In the present study, we report design, development and study of polyaniline (PANI) cladding modified fiber optic intrinsic glucose biosensor (FOIGB) for glucose sensing applications. Chemically and biologically sensitive material PANI has been exploited for the preparation of sensing element by cladding modification technique. Enzyme-glucose oxidase (GOx) was immobilized on porous supportive matrix of PANI using glutaraldehyde as a cross-linking agent. As-synthesized and deposited PANI film on fiber optic core was characterized by ultraviolet–visible and Fourier transform infra-red spectroscopies. X-ray diffraction and field emission scanning electron microscopy were employed to study structure and morphology of modified cladding. Sensing parameters, such as modal power distribution (MPD), sensing response, selectivity and stability were analyzed in order to study the performance of sensor. These parameters were determined by measuring change in optical power and MPD. The sensor, stored at a temperature 4 °C, showed lowest detection limit of 10 nM and found stable up to 36 days. It also showed good selectivity toward glucose and stability with high result reproducibility.