Human platelet electrorotation change induced by activation: inducer specificity and correlation to serotonin release

A Prominent Cell Manipulation Technique in BioMEMS: Dielectrophoresis

BioMEMS, the biological and biomedical applications of micro-electro-mechanical systems (MEMS), has attracted considerable attention in recent years and has found widespread applications in disease detection, advanced diagnosis, therapy, drug delivery, implantable devices, and tissue engineering. One of the most essential and leading goals of the BioMEMS and biosensor technologies is to develop point-of-care (POC) testing systems to perform rapid prognostic or diagnostic tests at a patient site with high accuracy. Manipulation of particles in the analyte of interest is a vital task for POC and biosensor platforms. Dielectrophoresis (DEP), the induced movement of particles in a non-uniform electrical field due to polarization effects, is an accurate, fast, low-cost, and marker-free manipulation technique. It has been indicated as a promising method to characterize, isolate, transport, and trap various particles. The aim of this review is to provide fundamental theory and principles of DEP technique, to explain its importance for the BioMEMS and biosensor fields with detailed references to readers, and to identify and exemplify the application areas in biosensors and POC devices. Finally, the challenges faced in DEP-based systems and the future prospects are discussed.

Separation of platelets from other blood cells in continuous-flow by dielectrophoresis field-flow-fractionation

We present a microfluidic device capable of separating platelets from other blood cells in continuous flow using dielectrophoresis field-flow-fractionation. The use of hydrodynamic focusing in combination with the application of a dielectrophoretic force allows the separation of platelets from red blood cells due to their size difference. The theoretical cell trajectory has been calculated by numerical simulations of the electrical field and flow speed, and is in agreement with the experimental results. The proposed device uses the so-called "liquid electrodes" design and can be used with low applied voltages, as low as 10 V(pp). The obtained separation is very efficient, the device being able to achieve a very high purity of platelets of 98.8% with less than 2% cell loss. Its low-voltage operation makes it particularly suitable for point-of-care applications. It could further be used for the separation of other cell types based on their size difference, as well as in combination with other sorting techniques to separate multiple cell populations from each other.