Dielectrophoresis of Amyloid-Beta Proteins as a Microfluidic Template for Alzheimer's Research.

We employed dielectrophoresis to a yeast cell suspension containing amyloid-beta proteins (Aß) in a microfluidic environment. The Aß was separated from the cells and characterized using the gradual dissolution of Aß as a function of the applied dielectrophoretic parameters. We established the gradual dissolution of Aß under specific dielectrophoretic parameters. Further, Aß in the fibril form at the tip of the electrode dissolved at high frequency. This was perhaps due to the conductivity of the suspending medium changing according to the frequency, which resulted in a higher temperature at the tips of the electrodes, and consequently in the breakdown of the hydrogen bonds. However, those shaped as spheroidal monomers experienced a delay in the Aß fibril transformation process. Yeast cells exposed to relatively low temperatures at the base of the electrode did not experience a positive or negative change in viability. The DEP microfluidic platform incorporating the integrated microtip electrode array was able to selectively manipulate the yeast cells and dissolve the Aß to a controlled extent. We demonstrate suitable dielectrophoretic parameters to induce such manipulation, which is highly relevant for Aß-related colloidal microfluidic research and could be applied to Alzheimer's research in the future.

Dielectrophoretic deformation of breast cancer cells for lab on a chip applications.

This paper presents the development and experimental analysis of a curved microelectrode platform for the DEP deformation of breast cancer cells (MDA-MB-231). The platform is composed of arrays of curved DEP microelectrodes which are patterned onto a glass slide and samples containing MDA-MB-231 cells are pipetted onto the platform's surface. Finite element method is utilised to characterise the electric field gradient and DEP field. The performance of the system is assessed with MDA-MB-231 cells in a low conductivity 1% DMEM suspending medium. We applied sinusoidal wave AC potential at peak to peak voltages of 2, 5, and 10 Vpp at both 10 kHz and 50 MHz. We observed cell blebbing and cell shrinkage and analyzed the percentage of shrinkage of the cells. The experiments demonstrated higher percentage of cell shrinkage when cells are exposed to higher frequency and peak to peak voltage electric field.

Dielectrophoresis-based microfluidic platforms for cancer diagnostics.

The recent advancement of dielectrophoresis (DEP)-enabled microfluidic platforms is opening new opportunities for potential use in cancer disease diagnostics. DEP is advantageous because of its specificity, low cost, small sample volume requirement, and tuneable property for microfluidic platforms. These intrinsic advantages have made it especially suitable for developing microfluidic cancer diagnostic platforms. This review focuses on a comprehensive analysis of the recent developments of DEP enabled microfluidic platforms sorted according to the target cancer cell. Each study is critically analyzed, and the features of each platform, the performance, added functionality for clinical use, and the types of samples, used are discussed. We address the novelty of the techniques, strategies, and design configuration used in improving on existing technologies or previous studies. A summary of comparing the developmental extent of each study is made, and we conclude with a treatment of future trends and a brief summary.