David S. Clague

The 2D electric field above a planar sequence of independent strip electrodes

This paper describes an analytical solution for the electrostatic potential and electric field in dielectrophoretic (DEP) microfluidic devices. DEP devices are engineered to be DNA concentrators in automated, flow-through systems of sample preparation for biological assays. DEP devices deflect and trap particles suspended in liquid flows because macromolecular particles polarize in response to an electric field, and the coupling of this polarization with the field alters particle motions. The DEP effect is proportional to ∇(EE). The electric field is produced by a sequence of independent strip electrodes and is two dimensional throughout the volume of the flow. As the potentials used in DEP devices are low-frequency sinusoids, the field of interest is the gradient of the squared root-mean-square (rms) of the electric field, ∇Erms2. An example of this field is shown.

Field-capable biodetection devices for homeland security missions

Biodetection instrumentation that is capable of functioning effectively outside the controlled laboratory environment is critical for the detection of health threats, and is a crucial technology for Health Security. Experience in bringing technologies from the basic research laboratory to integrated fieldable instruments suggests lessons for the engineering of these systems. This overview will cover several classes of such devices, with examples from systems developed for homeland security missions by Lawrence Livermore National Laboratory (LLNL). Recent trends suggest that front-end sample processing is becoming a critical performance-determining factor for many classes of fieldable biodetection devices. This paper introduces some results of a recent study that was undertaken to assess the requirements and potential technologies for next-generation integrated sample processing.

A Model-Based Processor Design for Smart Microsensor Arrays [Applications Corner]

In this article, we discuss the design of a smart-physics-based processor for microcantilever sensor arrays. The processor is coupled to a microelectromechanical sensor and estimates the presence of critical materials or chemicals in solution. We first briefly present microcantilever sensors and then discuss the microcantilever sensor array design, which consists of the cantilever physics propagation model, cantilever array measurement model, model-based parameter estimator design, and model-based processor (MBP) design. Finally, we end with experimental results and conclusions