Non-faradaic impedance characterization of an evaporating droplet for microfluidic and biosensing applications.

Lab Chip

School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN 47907, USA.

Published: July 2014

We have developed a general numerical/analytical theory of non-faradaic impedance of an evaporating droplet, and validated the model by experiments involving droplets of various analyte concentrations deposited on a surface defined by coplanar electrodes. The impedance of the droplet Z(n0,t,f) is analyzed as a function of the concentration (n0) of the ions in the solution, the measurement frequency (f) and the evaporation time (t). We illustrate the versatility of the model by determining the sensitivity enhancement α(t) of the droplet-based impedimetric nano-biosensor under different regimes of operation. The model should have broad applications in the characterization/optimization of droplet-based systems, especially lab-on-chip components involving digital microfluidics.

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Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4112542PMC
http://dx.doi.org/10.1039/c4lc00193aDOI Listing

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