Electrokinetic manipulation of microscopic biological particles, such as bacteria and other cells, is useful in the technology of lab-on-a-chip devices and micro-total-analysis systems (μTAS). In electrokinetic manipulation, non-uniform electric fields are used to exploit the dielectric properties of suspended biological microparticles, to induce forces and torques on the particles. The electric fields are produced by planar electrode arrays patterned on electrically-insulating substrates. Biological microparticles are dielectrically-heterogeneous structures. Each different type of biological cell has a distinct dielectric frequency response signature. This dielectric distinction allows specificity when manipulating biological microparticles using electrokinetics. Electrokinetic microbiological particle manipulation has numerous potential applications in biotechnology, such as the separation and study of cancerous cells, determining the viability of cells, as well as enabling more automation and parallelization in microbiological research and pathology. This paper presents microfabricated devices for the manipulation of biological microparticles using electrokinetics. Methods of impedance sensing for determining microparticle concentration and type are also discussed. This paper also presents methods of using digital signal processing systems to enhance the manipulation and sensing of the microbiological particles. A Field-Programmable Gate Array (FPGA) based system is demonstrated which is used to digitally synthesize signals for electrokinetic actuation, and to process signals for impedance sensing.
The ability of electrokinetics to manipulate biological microparticles, such as cells and bacteria, has great applications in Lab-on-a-chip devices, and micro-total analysis systems (mTAS). In these methods, non-uniform AC electric fields interact with the dielectric properties of suspended biological microparticles to induce forces and torques on the particles, in order to manipulate them. This is usually done using devices which are planar microelectrode arrays patterned on glass substrates. These devices usually exploit the fact that biological microparticles are dielectrically heterogeneous structures, and that each different type of biological particle has a distinct dielectric frequency response signature. This enables discrimination and selectivity of cells when manipulating electrokinetically. Electrokinetics in the form of Dielectrophoresis (DEP) and Travelling-Wave Dielectrophoresis (TWD) are used to induce rectilinear motion on suspended microparticles, whilst electrorotation is used to induce torques.
This paper presents a device for manipulating biological microparticles using electrokinetics. The device consists of planar metal electrode arrays patterned on glass. The device exploits the dielectric frequency response of the microparticles for manipulation as well as sensing.
Lab-on-a-chip BioMEMS devices have developed in recent years as a way to rapidly perform total biological analysis. With the complexity of fabrication of mechanical parts in microfluidic devices comes the desire to create devices which use alternative methods of pumping, mixing and manipulating fluids and suspended microparticles for reactions - such as electrokinetics. This paper presents novel ways of fabricating electrokinetic devices, which use the phenomenon of dielectrophoresis (DEP) for manipulation of suspended microparticles. Affects of driving waveforms are investigated. Visual results from microparticles are used to show the effect of operation of electrokinetic devices. Improved device designs and device operation are discussed.