Point of Care Detection of Blood Electrolytes and Glucose Utilizing Nano-Dot Enhanced Plasmonic Biosensor
Md. Farhad Hassan, Rakibul Hasan Sagor, Md. Ruhul Amin, Mohammad Rakibul Islam, M. Shah Alam
Abstract
To satisfy the requirements of label-free detection, low cost, fast response of a lab-on-chip biosensor, a nanodot enhanced metal-insulator-metal (MIM) waveguide based refractive index sensor coupled with three rectangular cavities, is proposed in this work. Numerical investigation of the transmission spectra, employing the finite element method (FEM), exhibits a linear correspondence with the refractive index, which is used to sense the unknown materials. Imposing a sequential optimization of the structural parameters and enhancing light-matter interaction by loading nanodots at the high E-field confined areas, desired sensitivity ( S) and figure of merit (FOM) are upgraded to 7564 nmRIU <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> - 1</sup> and 120, respectively. Additionally, the maximum temperature sensitivity of 3.40 nm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sup> C <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> - 1</sup> operating from 20 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sup> C to 70 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sup> C is also recorded for ploydimethylsiloxane (PDMS) sensing media. Prior to the selective detection of Na <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> +</sup> , K <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> +</sup> , and glucose concentration in the human blood, a sample preparation model combining purification, molecular separation, and concentration enhancement is proposed. Furthermore, a refractive index model is developed that exposes a maximum shift of 0.83 nm, 1.23 nm, and 8.72 nm of the transmittance peak for the concentration variation of 1 mgdL <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> - 1</sup> in Na <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> +</sup> , K <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> +</sup> , and glucose solution easily differentiable by the modern spectrometer. With such excellent performance metrics, compact size, and simple to use features, the proposed sensor is expected to bring a notable solution in the point-of-care detection.