Label free detection of white spot syndrome virus using lead magnesium niobate–lead titanate piezoelectric microcantilever sensors

We have investigated rapid, label free detection of white spot syndrome virus (WSSV) using the first longitudinal extension resonance peak of five lead–magnesium niobate–lead titanate (PMN–PT) piezoelectric microcantilever sensors (PEMS) 1050–700 μm long and 850–485 μm wide constructed from 8 μm thick PMN–PT freestanding films. The PMN–PT PEMS were encapsulated with a 3-mercaptopropyltrimethoxysilane (MPS) insulation layer and further coated with anti-VP28 and anti-VP664 antibodies to target the WSSV virions and nucleocapsids, respectively. By inserting the antibody coated PEMS in a flowing virion or nucleocapsid suspension, label free detection of the virions and nucleocapsids were respectively achieved by monitoring the PEMS resonance frequency shift. We showed that positive label free detection of both the virion and the nucleocapsid could be achieved at a concentration of 100 virions (nucleocapsids)/ml or 10 virions (nucleocapsids)/100 μl, comparable to the detection sensitivity of polymerase chain reaction (PCR). However, in contrast to PCR, PEMS detection was label free, in situ and rapid (less than 30 min), potentially requiring minimal or no sample preparation.