Metallic Layer-Based SPR Biosensor for Mycobacterium Tuberculosis Detection Employing Zinc Oxide and TMDCs Heterostructure

This article proposes three novel surface plasmon resonance (SPR) sensors designed on the basis of a Kretschmann configuration for mycobacterium tuberculosis (TBs) detection for the first time. The optimized sensor structures are sensor 1: BK7/Ag (55 nm)/ZnO (15 nm)/black phosphorus (BP) (0.53 nm), sensor 2: BK7/Au (50 nm)/ZnO (5 nm)/BP (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$5\times 0.53$ </tex-math></inline-formula> nm), and sensor 3:BK7/Ag (55 nm)/ZnO (15 nm)/BlueP/transition metal dichalcogenides (TMDCs) (0.75 or 0.78 nm). For the detection process, ten samples are taken with their refractive indices. This work analyzes the sensor’s performance by exploiting the transfer matrix method with the help of the angular interrogation technique at a wavelength of 633 nm. Initially, the thickness optimization of the metallic layer, ZnO, and TMDC is shown by observing the performance of minimum reflectance and sensitivity. Results declare that sensor 1 achieves sensitivity of 348.18°/RIU, quality factor (QF) of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$154.75~{\text {RIU}}^{-1}$ </tex-math></inline-formula>, detection accuracy (DA) of 3.40, and limit of detection (LOD) of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3.48 \times {{10}}^{-6}$ </tex-math></inline-formula>; sensor 2 attains 274.09°/RIU, QF of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$49.03~{\text {RIU}}^{-1}$ </tex-math></inline-formula>, DA of 1.08, and LOD of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3.89\times {{10}}^{-6}$ </tex-math></inline-formula>; sensor 3 accomplishes sensitivity of 331.36°/RIU, QF of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$220.91~{\text {RIU}}^{-1}$ </tex-math></inline-formula>, DA of 4.86, and LOD of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3.50\times {10}^{-6}$ </tex-math></inline-formula>. A detailed comparison of these innovative SPR sensors’ performance to recently released studies in the field of biomedical applications confirms their outstanding performance.