Optical biosensing of mycobacterium tuberculosis for point-of-care diagnosis

摘要

An optical biosensor is a compact analytical device formed by a bio-recognition sensing element integrated to an opticaltransducer system which translates a signal into a readable outcome that is measured by the detector. The target analyteinteracts with an immobile bio-recognition element giving rise to a signal proportionate to the concentration of ameasured analyte. Optical biosensors offer great advantages over conventional analytical techniques. Specifically, theycan provide multiple capabilities such as user-friendly operation, real-time analysis, rapid response, high sensitivity andspecificity, portability, label-free detection and cost-effectiveness. As a result, they possess suitable features critical forpoint-of-care diagnostics. In this study, a home-build surface plasmon resonance (SPR) optical biosensor device wasused to analyse interactions between the bio-recognition sensing element and an analyte on the biosensing layer. Thetransducer consisted of silica dioxide (SiO_2) substrate layer where a thin layer of gold was deposited. Mycolic acidantigens from mycobacterium tuberculosis (bovine strain) were immobilised on the biosensing layer and used as biorecognitionsensing elements to capture tuberculosis (TB) antibodies (analyte). From our findings, it was realised that themycolic acid successfully captured TB antibodies resulting in a detectable signal which paves a way for the developmentof the point-of-care device.