Design of a combined DEP-Raman system for cell stretching manipulation

This paper presents a microfluidic chip design that utilizes dielectrophoresis (DEP) tweezers to capture and stretch cells while measuring Raman spectra of cells under different deformations. The microfluidic chip is made of PDMS and glass slide bonded. The DEP force is generated that drives the cells to pass through the required area successively. A novel microelectrode with DEP tweezers is designed for cell manipulation. Based on the theoretical analysis of working principle of the DEP tweezers, the electrode structure consists of two probes, which are used as DEP tweezers to deform cells. The cell located between the two DEP tweezers can be stretched by the two DEP forces at the two ends of cell. The produced DEP force is strong enough to stretch the cell due to a strong electric field generated around the probe-end. The probe electrode is fabricated using MEMS technology. Advantages of the proposed design for cell manipulation include non-contact, low-damage and relatively easy implementation. The Raman spectra of cells can be measured through stretching the cells using the DEP force. By comparing the Raman spectra of the cells under different deformations, cell mechanism can be further probed.