Green-synthesized iron-zinc oxide nanomaterials immobilized on Morus alba sawdust for highly sensitive optical glucose sensing.

Glucose is a prime source of energy for the human body, and its concentration is a vital biomarker for various pathological conditions. Despite the availability of multiple platforms for glucose sensing, significant efforts are still needed to develop a complete package that is inexpensive, easy to operate, rapid, environmentally friendly, and sensitive. The current work capitalizes on the presence of reductants in Citrus sinensis and the porous surface morphology of Morus alba sawdust. We deposited iron and zinc oxide on sawdust as an ingenious approach to enhance electron mobility in the fabricated system. The synthesized material, i.e., iron and zinc oxide deposited on sawdust (Fe-ZnO@SD), was characterized through UV-Vis spectroscopy, FTIR spectroscopy, XRD, SEM, and elemental mapping. The proposed method was successfully applied to detect glucose using the chromogenic substrate tetramethylbenzidine (TMB). We optimized various parameters that play a vital role in the sensor's performance. Under the optimized conditions, the fabricated sensor detected glucose over a wide linear range of 9-81 µM, with an R 2 of 0.996 and LOQ and LOD of 0.57 and 0.17 µM, respectively. The selectivity of the fabricated sensor was confirmed in physiological solutions and urine samples, exhibiting high linearity within the tested concentration ranges.