Application of long-range surface plasmon for sensitive detection of Human E.coli

A novel biosensor for sensitive detection of concentrations of Human E.coli was developed.This biosensor was based on long-range surface plasmon resonance(LSPR),using magnesium fluoride(MgF2) as a dielectric buffer layer and silver(Ag) as a sensing layer.In LSPR-based biosensor,an optimum sensor design could reduce the resonance width,resulting in higher sensitivity to the bulk refractive index changes.The multilayer structures and experimental set-up were prepared.Performance of the LSPR-based biosensor was compared to that of the conventional surface plasmon resonance(CSPR) biosensor in series of experiments.The results show the resonance width of the LSPR-based biosensor is 1.79-fold narrower than that of the CSPR-based biosensor.In addition,the sensitivity of the LSPR-based biosensor is up to 2-fold greater than that of CSPR-based biosensor for Human E.coli.