The integrated microfluidic systems laboratory is an experimental research lab that focuses on microfluidic flow visualization (including micro particle image velocimetry) and microfabrication of such platforms. We also investigate electrokinetic methods in microfluidic systems for particle and cell manipulation and analysis. Below is a list of ongoing research projects in our laboratory.
We rely on flow visualization for a significant portion of our research. The most direct approach is to seed fluid with particles and apply PIV or PTV algorithms to analyze their trajectory. These techniques can be applied at the microscale and macroscale.
Our group has expertise in microscale electrokinetic mechanisms including dielectrophoresis (DEP) and electrohydrodynamics including AC electro-osmosis and electrothermal flow. These techniques offer sample manipulation schemes without moving parts and, in most cased, straightforward microfabrication techniques. Most of these mechanisms can be driven with a standard benchtop waveform generator with electric fields on the order of 106 V/m.
Nanoparticles & Stability
Sample stability (i.e. prevention of particle aggregates) is a function colloid zeta potential, nanoparticle charge, and nanoparticle concentration. The image below shows a time-lapse of microparticle behavior on the International Space Station. We have also investigated the formation of agglomerations in bourbon whiskey for quality control.
Impedance spectroscopy (aka EIS) is a non-invasive, real-time technique than can measure the dielectric characteristics of a sample. We have applied this technique in a microfluidic chip to monitor the integrity of an endothelial monolayer in vitro . We can monitor the response of the endothelium when subjected to external mechanical and chemical stimuli.
Rapid Electrokinetic Patterning (REP)
REP is a technique that can manipulate colloids on an electrode surface dynamically through the use of reconfigurable illumination patterns. Our research team and collaborators have been able to translate, trap, sort, and manipulate microparticles (magnetic, metallic, and insulative), nanoparticles, bacteria, and carbon nanotubes. REP can be executed optically with a laser or broad light source (patterned using a traditional overhead projector) or without illumination through the use of integrated resistive heaters.
Electrostatic Deposition and Repulsion
Electrostatics can be used for the deposition or repulsion of particles. We have studied the behavior of an electric curtain and how particles are repelled under certain conditions.
Our laboratory is investigating various methods of depositing colloids onto the surface of surfaces with various physical properties. For example, Kentucky bourbon has interesting surfactant and polymer-like properties that form porous-like colloid layers after liquid evaporation.
We acknowledge the support of Ultra Motion (www.ultramotion.com) for the use of precise linear actuators that aid in this investigation.