Electrokinetic Separation of Cells Using Ionic Liquids (ILs) Catalysts

Characterization and analysis of rare cells demonstrate critical cues for early diagnosis of chronic diseases. Electrokinetic cell separation methods have been previously established to have greater efficiency when compared to traditional flow cytometry methods. It has been shown by many researchers that buffer solutions in which cells are suspended in have enormous effects on producing required dielectrophoretic forces to separate and manipulate cells. Most commonly used suspension buffers used to electrokinetically manipulate cells are deionized water and cell media. However, these solutions exhibit high level of intrinsic noise, which greatly masks the electrokinetic signals from cells under study. Ionic liquids show promise towards the creation of conductive fluids with required electrical properties. The goal of this project is to design and test tailored ionic liquid compositions for enhancing dielectrophoretic forces on cells while creating an environment for preserving their integrity. We analyzed three uniquely synthesized methylimidazolium based ionic liquids with low half maximal inhibitory concentration was used as suspension medium for cell separation. These dicationic ionic liquids possess slight electrical and structural differences with high thermal stability. The three ionic liquids were tested for cytotoxicity and their ability to enhance signals from cells. We performed tests using organic particles (HeLa cells) and inorganic particles (synthetic beads). Separation yield, system efficiency, purity and recovery of isolated cells were calculated including cell viability. The effects of electrical neutrality, charged particle effects, free charge screening due to ionic liquids and their contribution towards enhanced electrokinetic signals from cells were studied. We were able to achieve improved system resolution (upto 95%) with no harmful effects on cells.