THIOL FUNCTIONALIZED GOLD NANOBIPYRAMIDS- BASED PLASMONIC SENSOR FOR GLUCOSE DETECTION

Gold nanobipyramids (GNBPs) have high selectivity in detecting changes in their surrounding medium because of their electric field enhancements and larger surface areas. In this study, we functionalized GNBPs using a thiol group that acts as a ligand to improve the detection performance of the analytes. The investigation is carried out by varying the functionalization periods from 12 to 72 hours. The optimum thiol-functionalized GNBPs (t-GNBPs) are obtained in 60 hours, with a length of 36.84 +/- 2.05 nm, a width of 24.02 +/- 0.74 nm, and an aspect ratio of 1.54 +/- 0.11. Then, the optimum t-GNBPs are used as a sensing material in a plasmonic sensor to detect glucose. The limit of detection (LoD) of glucose is 1 mu M for this sensor. The plasmonic sensor has been successfully built with reliable performance in detecting glucose with excellent linearity, sensitivity and R2 = 1; good selectivity compared to four similar chemical structure analytes; high stability with a low error value, i.e., +/- 0.02 a.u.; and almost consistent repeatability values in each cycle with low percent variance of 0.000025% for the t-SPR area and 0.000032% for the l-SPR area. Therefore, a plasmonic sensor based on t-GNBPs is an alternative method of detecting glucose with high sensitivity, selectivity and repeatability.