pH based urea biosensing using fluorescein isothiocyanate (FITC)-dextran encapsulated micro-carriers of calcium alginate

Abstract

Kidney disease prevalence can be significantly reduced by early analyte (pH, urea, creatinine etc.) detection using a specific and sensitive technique. The research aims at developing a fluorescent assay for pH and Urea based on FITC-dextran (FD)-Urease co-immobilized alginate nano, micro and nano-in-micro carriers. Urea biosensor performance for FD-Urease nano/microcarriers was validated for accuracy, response time, linearity, range, intra-day/inter-day reproducibility and stability. Results indicated that pH detection is possible in the range 4-8 units using uniformly sized (50 ±10 μ) FD loaded alginate microspheres (FDAM) with a regression coefficient of 0.962. The linear regression analysis showed an R2 of 0.994 and 0.989 (0-10 mM) for FD-Urease loaded alginate microspheres (FUAM) and FD loaded in alginate nanoparticles which are co-immobilized in alginate microspheres along with urease (FUANM), respectively. Nano-in-Micro formulations of pH and urea biosensor showed a higher stability for ∼30 days within the detection range of 0-10 mM in contrast to 7 days stability of FUAM. The pH and Urea biosensors were found to be accurate and reproducible with % recovery values in the range of 96-112% with a response time of 7-8 minutes. Hence, FD-Urease co-immobilized alginate microspheres show a great potential to be translated as a pH and urea biosensor for early detection of kidney diseases. Copyright © 2016 American Scientific Publishers.