Uric acid biosensor based on chemiluminescence detection using a nano-micro hybrid matrix

Uric acid (UA) is a nitrogenous end product of the purine catabolism in humans. Excessive production of UA may lead to hyperuricemia, gout, and kidney disorders. The study aims at developing an indirect enzymatic UA biosensing assay based on H2O2 detection. The UA biosensing assay was prepared by loading pentacene in peroxalate nanoparticles and Uricase co-immobilized in alginate microspheres. These biosensing formulations were characterized using DLS, optical microscopy, SEM, TEM, and CLSM. Nanoparticles embedded in alginate microspheres formed were used for H2O2 and UA sensing. The dye loaded nanoparticles and co-encapsulated microspheres were formed with size ranges from 520 nm and 60 μm, respectively. Uricase loading using atomization evaluated using Bradford assay was found to be greater than 98% in all tested concentrations. Sensing studies for H2O2 and UA were carried out using fluorescence spectroscopy. H2O2 could be detected in a linear range of 0–6 μM with a regression coefficient of 0.979 and in a range of 6–50 μM with a regression coefficient of 0.984. The limit of detection for each of the range was found to be 1 and 3 μM, respectively. UA sensing showed regression constant 0.977 and 0.949 in range of 0–0.1 mg/ml and 0.015–0.04 mg/ml, respectively. Thus chemiluminescent alginate microspheres containing peroxalate nanoparticles co-immobilized with uricase can be used as diagnostic markers for detection of UA.