Effect of composition and calcination on the enzymeless glucose detection of Cu-Ag bimetallic nanocomposites

Abstract Development of novel materials that are capable of sensing blood glucose in absence of enzymes could be highly beneficial for affordable diabetic care. The present work discusses the effect of composition and heat treatment on the glucose sensing ability of bimetallic Cu-Ag nanocomposites. Polyol reduction method was employed to prepare nanocomposites with five different Cu:Ag molar ratios viz. 1:1, 2:1, 3:1, 1:2 and 1:3. The nanocomposites were thoroughly characterized by XRD, XPS, EDS, and TEM imaging. The nanocomposite having equimolar ratio of Cu and Ag was the best among the prepared samples having a high sensitivity of 1340 µAmM-1 cm-2 with a detection limit of 0.6 µM at S/N = 3. The nanocomposite has noticeable linear response for glucose concentration ranging from 0.01 to 30 mM, with R2 value of 0.9926. The nanocomposite has very high selectivity, stability and good reproducibility with a very low sensitivity loss of 4.1% after 20 days. A good correlation was obtained with the pathology laboratory data for real blood samples. Moreover, a three-fold increase in sensitivity was observed on calcining the nanocomposite at 600 °C making this sample one of the best sensor materials having high sensitivity, low detection limit with vast linear response range.