Ultrasensitive polyaniline-nickel oxide cladding modified with urease immobilized intrinsic optical fiber urea biosensor

Herein, we report a polyaniline-nickel oxide (PANI-NiO) nanocomposite as an efficient immobilization matrix for development the optical fiber urea biosensor. Optical fiber sensing probe was developed by removing some portion of optical fiber at middle and modified with PANI-NiO matrix. After the modification of cladding removed portion, it was immobilized with enzyme urease via glutaraldehyde as a bi-functional cross-linking agent. The physicochemical and optical properties of the PANI-NiO matrix were explored by X-ray diffraction, scanning electron microscopy, ultraviolet-visible, and Fourier transform infrared spectroscopic techniques. The characteristic features and performance of the developed sensor were evaluated via recording the output power and modal power distribution by means of a charge-coupled device camera. The developed urea biosensor exhibits a selective response towards urea concentrations in the linear range 1 nM-100 mM with a lower detection limit of 1 nM. Sensor recorded as a 40 days stability and response time similar to 1 min. Thus, the obtained experimental results of the developed sensor promote its applicability with practical prospects in diverse field.