Design of a Plasmonic Sensor Using Inter-coupled Gold Nanorods for Glucose Detection in Urine

In this paper, the performance of an array of gold nanorods (GNRs) as a glucose sensor is investigated using the finite-difference-time-domain (FDTD) simulation method. The array consists of two sets of GNR tetramer structures, where each GNR in the tetramer is coupled with the neighboring one. Inter-coupling between GNRs is used in this work to enhance the sensitivity. Each rod is 112 nm in length and 40 nm in width, and the gap between the adjacent rods in the tetramer is 30 nm to ensure inter-coupling between them. The work is applicable where GNRs are fabricated by the electron beam lithography (EBL) process, as a fixed distance between rods in the tetramer is required to ensure inter-coupling between them. It was found that the sensor has a sensitivity of 537 nm per refractive index unit (RIU) and a detection limit of 10(-3). The performance of the sensor is satisfactory for detecting different concentrations of glucose in urine. It can be said that the proposed GNR-based sensor exploiting the inter-coupling effect can be very promising in the biomedical field.