Multiparametric MEMS Biosensors With Integrated Impedance Spectroscopy and Gravimetric Measurements for Water Toxicity Sensing

This paper presents the design, fabrication and characterization of a novel multiparametric microelectromechanical (MEMS) biosensor based on live mammalian cells with capabilities of sensing the toxicity of field water with minimized false-positive rate. This biosensor combines two biosensing techniques, resonant frequency measurements and electric cell-substrate impedance sensing (ECIS) on a single chip. The sensor is based on the innovative placement of the working microelectrode for ECIS technique as the upper electrode of a quartz crystal microbalance (QCM) resonator. This multiparametric biosensor was characterized with bovine aortic endothelial cells (BAECs). Toxicity tests to study BAECs responsiveness to health-threatening concentrations of ammonia in de-ionized water as a toxicant model will also be presented. The increase of the resonant frequency and decrease of impedance of the biosensor indicated the detachment of cells as a result of toxicant stimulation of ammonia solution. These gravimetric and impedimetric measurements on the same cell monolayer demonstrate that the multiparametric biosensor is able to perform two types of measurements simultaneously and this sensor can successfully be tested with drinking water containing toxicants.