Neurons as sensors: Individual and cascaded chemical sensing

Department of Chemical and Environmental Engineering, University of California, Riverside, Riverside, California, United States
Biosensors & Bioelectronics (Impact Factor: 6.41). 08/2004; 19(12):1599-610. DOI: 10.1016/j.bios.2003.12.013
Source: PubMed


A single neuron sensor has been developed based on the interaction of gradient electric fields and the cell membrane. Single neurons are rapidly positioned over individual microelectrodes using positive dielectrophoretic traps. This enables the continuous extracellular electrophysiological measurements from individual neurons. The sensor developed using this technique provides the first experimental method for determining single cell sensitivity; the speed of response and the associated physiological changes to a broad spectrum of chemical agents. Binding of specific chemical agents to a specific combination of receptors induces changes to the extracellular membrane potential of a single neuron, which can be translated into unique "signature patterns" (SP), which function as identification tags. Signature patterns are derived using Fast Fourier Transformation (FFT) analysis and Wavelet Transformation (WT) analysis of the modified extracellular action potential. The validity and the sensitivity of the system are demonstrated for a variety of chemical agents ranging from behavior altering chemicals (ethanol), environmentally hazardous agents (hydrogen peroxide, EDTA) to physiologically harmful agents (pyrethroids) at pico- and femto-molar concentrations. The ability of a single neuron to selectively identify specific chemical agents when injected in a serial manner is demonstrated in "cascaded sensing".

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    • "This technique was simple, but had large bounds of error. That is because at the low concentration regimes, especially in the case of chemical mixtures, it has been established that there is a slight shift in the frequency peak (±5 Hz) (Prasad et al., 2004). The shift was also observed in the case of individual chemical analytes (Yang et al., 2003). "
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