LSPR biosensor with dual-channel for simultaneous multianalyte detection Simitha S 1 , Shinto M Francis 2 , Jesly Jacob* 2 and Vibin Ipe Thomas* 1 1 Department of Chemistry, CMS College, India, 2 Department of Physics, Assumption College, Kerala Corresponding authors : vibin@cmscollege.ac.in, jeslyjacob@assumptioncollege.edu.in A surface plasmon resonance (SPR) based sensor with multiple sensing cavities is proposed for the qualitative and quantitative analysis of biochemical analytes, antigen-antibody interaction, DNA/RNA binding, etc. Detection and analysis of different analytes by means of the proposed dual-channel based plasmonic structure is numerically analysed using finite element method via absorption cross-section profiles. The sensor structure consisted of two segments of a square silver disc and ring with a channel/cavity in between acting as the sensing region. The optical sensor monitors the change in resonance position corresponding to the field localization near plasmonic channels accompanied by the change of refractive index of the analyte embedded in the cavity. A maximum refractive index (RI) sensitivity of 1778.16 nm/RIU is obtained for concentration analysis of 0.07- 0.12g/ml glucose-lactose solution via their respective RI values. The dual absorption peak maxima obtained with multiple analytes in each channel indicates the independent sensing behaviour of the structure that can potentially quantify multiple analytes simultaneously. Further, when only a single analyte is loaded in both cannels, merging of the two peaks into a single peak with equal charge distribution on both cavities is observed which in turn finds the possible single or multiple analyte detection. Moreover, the independent sensing behaviour can be effectively tuned with changing the material or geometric parameter of any one of the segments. The proposed structure exhibits a super ultra-broad RI sensing range of nearly 0.4 to 1.8 RIU with resonant peaks across near-IR region. The reduction of size of the sensing channel to 10 nm further improves the performance. Sensitivity, figure of merit (FOM), and Q-factor values of 4267.60 nmRIU -1 , 82.23 RIU -1, and 116.51 observed after optimization reveal the promising applicability of designed SPR sensor in the areas of medical diagnostics, pharmaceuticals, chemical industries, and food processing. Those simultaneous sensing channels proposed promises repeated confirmation analysis, analyte comparison study, and multi-parameter detection together with the advantage of simple and easy manufacturable structure profile. References 1. S. Sasi, S. M. Francis, J. Jacob and V. I. Thomas, Plasmonics , , DOI:10.1007/s11468-021-01418-5. 2. S. S, S. M. Francis, A. Ramachandran, J. Jacob and V. Ipe Thomas, Opt. Laser Technol. , 2022, 149 , 107853.
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