A qualitative, cut-off (mid pg mL−1) biosensor assay alternative for bacterial endotoxin is described. Detection is based on the acoustic wave physics of the highly sensitive, ultra-high frequency ‘electromagnetic piezoelectric acoustic sensor’ (EMPAS) transducing device. The biosensing platform features dual-functional, binary organosiloxane adlayer surface chemistry (on quartz resonator discs) combining high binding affinity for the target analyte with pronounced antifouling properties against biological matrix sample interferents. Unlike current clinical tests, measurements are performed in a real-time and label-free advanced fashion, using full human blood plasma microsamples (50 μL). Another highlight of this work is the rapidity with which analysis is completed (∼35 min per replicate).
