Novel superabsorbent biosensor nanohydrogel based on gum tragacanth polysaccharide for optical detection of glucose

Effective biosensor devices for detection of glucose based on carbohydrate polymer nanohydrogels have been scarcely reported to date. In an attempt to construct a more functional device for detection of blood glucose, CdTe quantum dots (QDs) and glucose oxidase (GOx) were immobilized within the well functionalized superabsorbent nanohydrogel prepared from the nanoparticles (<50 nm) of gum tragacanth (GT) polysaccharide. The biosensor was able to perform enzyme-catalyzed oxidation of glucose to produce H₂O₂, a product that subsequently quenched the fluorescence emission. The quenching rate depends on the glucose concentration, the detection limit was 0.5 mM, and the Michaelis-Menten constant (K_M) was an excellent value of 2.2 mM. The prepared biosensor was used for the enzymatic detection of blood glucose concentration in the real serum samples which exhibited satisfactory reproducibility and accuracy. Therefore, the high immobilization for QDs and GOx in this superabsorbent nanohydrogel matrix can be a suitable diagnostic device for biomedical applications.