Direct optical immunosensing (sensitivity and selectivity)

Abstract This paper compares theoretically predicted detection limits of three optical sensing devices (surface plasmon resonance, input grating coupler, difference interferometer) with the experimentally found detection limits for anti h-IgG antibodies. The theoretically predicted sensitivities of these sensors are confirmed satisfactorily by experiments. The influence of high concentrations of non-analyte proteins on direct immunosensing with such optical transducers is investigated in the detection of HBsAg (hepatitis B surface antigen) using undiluted human serum with a sensitized surface plasmon resonance sensor; no serious influence was found.