Piezoelectric Crystal Biosensor System for Detection of Escherichia Coli

Abstract
A piezoelectric crystal biosensor system was applied to the detection of Escherichia coli. the system consists of an oscillator, a frequency counter, a flow cell and a modified piezoelectric crystal. Anti-E. coli antibody is immobilized on the surface of the crystal. It is used as an E. coli detection by measuring its resonant frequency shift due to a mass change caused by specific binding of the micro organisms to the surface. the frequency shift correlates with an E. coli concentration in the range of 106−108 cells·cm−3. the resonant frequency shift is increased by further treatment to bind micro-particles modified with anti-E. coli antibody. This method allows us to improve the determination limit to 105 cells · cm−3.