Preparation and Experimental Study on Dielectrophoresis- Based Microfluidic Chip for Cell Patterning / 分析化学

Adielectrophoresis-basedmicrofluidicchipappliedtocellspatterningisdesignedandfabricated, and it demonstrates non-contact and batch manipulation of cells. The microfluidic chip employs a PDMS microchannel and two ITO electrodes, which are designed as astep shape. The distribution of electric field caused by the microelectrodes is simulated by finite element simulation software, COMSOL. The position of the maximum intensity of electric field is also determined. The ITO microelectrodes and the PDMS microchannel are fabricated using MEMS fabrication process. After oxygen plasma surface treatment, the PDMS microchannel and glass substrate with the ITO microelectrodes are aligned and bonded to form experimental microfluidic chip. Through DEP experiment with the varying frequencies, DEP response of yeast cells is examined, and the electric field frequency of the both positive and negative DEP responses are confirmed. The results showed that yeast cells in solution conductivity of 60 μS/cm had negative DEP movement at the frequency of 1 kHz to 10 kHz, positive DEP movement at the 500 kHz to 10 MHz, and no DEP movement at the 50 kHz. Under the condition of the sinusoidal potential of 8Vp-p and the electric field frequency of 5 MHz, the yeast cells were aligned into chains along the step edge of microelectrodes.

Simple and Novel Three Dimensional Neuronal Cell Culture Using a Micro Mesh Scaffold

Conventional method of cell culture studies has been performed on two-dimensional substrates. Recently, three-dimensional (3D) cell culture platforms have been a subject of interest as cells in 3D has significant differences in cell differentiation and behavior. Here we report a novel approach of 3D cell culture using a nylon micro mesh (NMM) as a cell culture scaffold. NMM is commonly used in cell culture laboratory, which eliminates the requirement of special technicality for biological laboratories. Furthermore, it is made of a micro-meter thick nylon fibers, which was adequate to engineer in cellular scales. We demonstrate the feasibility of the NMM as a 3D scaffold using E18 rat hippocampal neurons. NMM could be coated with cell adhesive coatings (polylysine or polyelectrolyte) and neurons showed good viability. Cells were also encapsulated in an agarose hydrogel and cultured in 3D using NMM. In addition, the 3D pattern of NMM could be used as a guidance cue for neurite outgrowth. The flexible and elastic properties of NMMs made it easier to handle the scaffold and also readily applicable for large-scale tissue engineering applications.