“…Therefore, molecular affinity interactions occurring at the sensor surface could be detected without using any reporter labels. Since the advent of SPR for biosensors, SPR technique has been explored for detection of a wide range of biological markers relevant to medical diagnosis, food quality, etc., such as cardiac troponin, enterotoxins and microorganisms (Gaus and Hall, 1998;Sonezaki et al, 2000;Homola et al, 2002b;Wei et al, 2003;Cui et al, 2003;Nakatani et al, 2004). Sensitivity of SPR measurement is directly related to the amount and MW of the analyte that binds to the sensor surface, and thus SPR is highly disadvantageous for detection of small molecules (MW < 1 kDa).…”