Abstract
Bacterial pathogens are crucial targets for detection and identification in areas such as medicine, food safety, public health, and security. Worldwide, bacterial infections are a leading cause of morbidity and mortality. Even with the availability of antibiotics, these infections are often misdiagnosed or diagnosis is delayed, resulting in significant health risks. This study introduces a Thallium bromide (TIBr) immobilized single-mode fiber (SMF)-based surface plasmon resonance (SPR) biosensor, specifically designed to detect bacterial cells in clinical and food-related samples. The sensor incorporates ZBLAN and NaF as core and cladding materials, while a combination of silver (Ag) and TIBr is used to improve analyte detection and maximize sensitivity. The performance of the TIBr-immobilized SPR biosensor is evaluated against traditional Ag-based systems by optimizing the TIBr layer thickness relative to the Ag layer. The sensor’s wavelength-dependent response, sensitivity, and figure of merit (FOM) are calculated for various sensing media, including water, Arthrobacter crystallopoietes (rod form), Bacillus megaterium KM, and Micrococcus lysodeikticus 4698. The results demonstrate that the sensor achieved a maximum sensitivity of 9375 nm/RIU for M. lysodeikticus 4698 and a maximum FOM of 78.469 RIU−1 for A. crystallopoietes. The optimized sensor structure, incorporating TIBr on the Ag layer, significantly enhances both sensitivity and FOM compared to sensors with bare Ag layers.
