Surface plasmon resonance-based biosensor for accurate and rapid detection of Mycobacterium tuberculosis

Tuberculosis causes severe health impacts and remains a leading global killer. Delayed diagnosis prolongs infectiousness and worsens patient outcomes, so rapid detection is essential for timely treatment and to curb further spread. This research explores a highly sensitive optical surface plasmon resonance (SPR) biosensor designed for the rapid and accurate detection of Mycobacterium tuberculosis. The sensor structure comprises a multilayered configuration of $Ca{F}_2$ / $Si{O}_2$ /Ag/AlON/BP, optimized for enhanced plasmonic response and biological interaction. Numerical simulations using the transfer matrix method (TMM) demonstrate that the proposed design achieves a maximum angular sensitivity of 615.33 deg./RIU. The finite element technique is used to verify the results of the sensor. Performance metrics such as full width at half maximum (FWHM), quality factor (QF), signal-to-noise ratio (SNR), detection accuracy (DA), and figure of merit (FOM) were systematically evaluated, highlighting the sensor's capability for precise detection within the biological refractive index range of 1.29 to 1.35. The sensor achieves a peak QF of 275.29 RIU $_{}^{-1}$ , DA of 0.50 deg $_{}^{-1}$ , SNR of 2.20, FOM of 1206.3 RIU $_{}^{-1}$ , and a minimum FWHM of 2.66 $_{}^{\circ }$ . A comparative analysis using TMM and finite element method (FEM) was carried out to validate the reflectance results. Compared with previously reported SPR sensors, our design exhibits superior sensitivity and overall performance of the proposed design. These findings highlight the innovation of integrating BP and AlON into a $Ca{F}_2$ -based prism structure, offering a promising pathway for highly sensitive and non-invasive tuberculosis diagnostics.