Immobilization of CdTe QDs on Glucose-Imprinted Alg-g-P(AA-co-VPBA) Nanocomposite for Optical Sensing of Glucose.

Developing a highly sensitive, selective, and biocompatible nanobiosensor for glucose monitoring remains a significant challenge in biomedical diagnostics. In this research, the design and synthesis of a highly sensitive and selective nanobiosensor for glucose detection were reported, utilizing cadmium telluride quantum dots (CdTe QDs) immobilized on a glucose-imprinted sodium alginate-graft-poly(acrylic acid-copolymer-vinylphenylboronic acid) nanocomposite. The preparation method is notable for its safety, cost-effectiveness, and use of biocompatible materials. The nanobiosensor was synthesized by modifying CdTe QDs with a biopolymer chain comprising acrylic acid, sodium alginate, and vinylphenylboronic acid (VPBA), resulting in a glucose-sensitive and selective sensor with an average hydrodynamic diameter of 32 nm. Glucose detection was achieved through fluorescence quenching of CdTe QDs upon binding glucose molecules to VPBA moieties via cis-diol interactions, facilitating glucose sensing. A linear correlation was established between fluorescence intensity and glucose concentration, with a detection limit of 0.164 μg/mL. The sensor exhibited high specificity for glucose over potential interfering species, including various amino acids, fructose, lactic acid, and metal ions, even at concentrations 100 times higher than glucose. In practical applications, the sensor demonstrated high recovery rates ranging from 98.72 to 101.36% in human serum and urine samples, indicating its efficacy and specificity in complex biological matrices. The nanobiosensor also showed excellent repeatability and reproducibility with a relative standard deviation (RSD) of 1.25 and 1.38% for five replicates, respectively, and stability over 28 days with consistent fluorescence response. These results suggest that the glucose-imprinted Alg-g-P(AA-co-VPBA)/CdTe QDs nanobiosensor is a promising candidate for sensitive, selective, and glucose-monitoring applications.