Development and evaluation of surface plasmon resonance phase difference for tuberculosis detection

Tuberculosis (TB) is a major global health issue. To address this, there is a need for rapid and highly sensitive diagnostic methods. Surface plasmon resonance (SPR) is a promising optical sensing platform for various medical applications due to its high sensitivity and label-free detection. In this study, we introduce and evaluate surface plasmon resonance phase difference (SPR-PD) as a novel approach for TB detection. Our method uses the optical properties of SPR-PD to monitor the interaction between MPT64 biomarkers and immobilized MPT64 antibodies on a sensor surface. MPT64 antibodies were immobilized on a gold-coated biosensor chip and the MPT64 TB antigen was added to the biosensing surface. To enhance the detection signal for biomolecular binding events, gold nanoparticles (AuNPs) were conjugated to the MPT64 secondary antibodies. Ultraviolet-visible (UV-vis) spectroscopy was used to characterize the conjugation. The optimized biosensor chip was then analyzed using the custom-built SPR-PD system. Our preliminary results demonstrate successful immobilization of MPT64 antibodies on the biosensing surface, facilitating the capture of MPT64 TB antigen. Furthermore, SPR-PD provides real-Time insights into the binding events and enables the sensitive and specific detection of MPT64 TB antigen. Our findings highlight the successful detection of TB biomarkers.