Development and application of side-polished fiber immunosensor based on surface plasmon resonance for the detection of Legionella pneumophila with halogens light and 850 nm-LED

An immunosensor using side-polished optical fiber based on surface plasmon resonance was proposed for the detection of Legionella pneumophila with 850 nm LED and halogens light source sensing system. The sensing fiber had side-polished down to closing half the core and coated a 37 nm gold thin film by dc sputter. The detection surface was fabricated by binding chemically to self-assembly monolayer (SAM) of 11-mercaptoundecanoic acid (MUA) on gold (Au) surface, and then was activated by EDC/NHS. The formation of antibody immobilization on an MUA treated surface and the binding of antigen, L. pneumophila, in series were confirmed by SPR response. The SPR curve on the optical spectrum was described on the optical spectrum analyzer (OSA) and had a width wavelength of sensing range of SPR effects. The intensity of the transmitted light was decreasing linearly by SPR effect with increasing antigen, L. pneumophila. Two measurement system using the halogens light source and 850 nm-LED was constructed for several real-time detections that have been carried out for the measurements of the index liquid detections for the sensitivity analysis. The adsorption variation of every process could be observed significantly on The SPR effect in spectrum and powermeter. An immnuosensor based on SPR with two measurement systems, spectrometer with halogen light and powermeter with 850 nm-LED for the detection of L. pneumophila was obtained the same result; the detection limit was 101 CFU/ml, which was advantageous or comparable to presently available immunosensors reported for bacterial detection. The current fabrication technique of a SPR immunosensor using optical fiber for the detection of L. pneumophila could be applied to construct other biosensor.