Real-time, in situ DNA hybridization detection with attomolar sensitivity without amplification using (pb(Mg1/3Nb2/3)O3)0.65-(PbTiO3)0.35 piezoelectric plate sensors

摘要

In this paper we have investigated real-time, in situ DNA hybridization detection using piezoelectric plate sensors (PEPSs) consisting of a highly piezoelectric lead magnesium niobate-lead titanate (PMN-PT) layer 8μm in thickness thinly coated with Cr/Au electrodes and electrically insulated with 3-mercaptopropyltrimethoxysilane (MPS) encapsulation. With probe complementary DNA (cDNA) immobilized on the PEPS surface and by monitoring the first longitudinal extension mode (LEM) resonance frequency shift of the PEPS we detected hybridization of the target DNA (tDNA) to the probe cDNA on the PEPS surface in real time at concentration 1.6×10~(-18)M with a signal to noise ratio of 8 without isolation and amplification at room temperature in 30min in phosphate buffered saline (PBS) solution. The detection was validated in situ by two different methods: (1) the detection of fluorescently labeled microspheres coated with reporter cDNA complementary to the tDNA but different from the probe cDNA; (2) fluorescent visualization.