Abstract
Single cell microarrays is a potential tool for cellular assay. It has an advantage of high throughput screening and promotes the study at the single cell level. This research proposed a novel device and methodology to pattern single cell microarrays. Structural DEP force and image-based DEP force were produced to control the spatial distribution of cells on the chip. Microwell arrays made by dielectric material were as physical barriers for enhancement of cell immobilization. Cells can immobilize well against the hydrodynamic drag force by using dielectric microstructures. The concept of DEP energy wells was used to explain the distribution of single cell microarrays for the first time. Cells which suspended in the medium were located at unstable energy state and moved toward stable energy state. Finally, cells could stay stably in the bottom edge of the microwells owing to the lowest energy positions. Using this new approach, single cell occupancy was enhanced to 45%±1.5% than only 28%±2.0% by gravitational force in lower cell seeding density. In higher cell seeding density, single cell occupancy was enhanced to 72%±2.3% than 35%±1.9% by naturally gravitational sedimentation. The maximum matrix of single cell microarrays will be close to 100*100 under proficient handling. There was a possible optimized cell seeding density for this research in the range from 7.3×10^7 to 1.5×10^8 (cells/mL). Saccharomyces cerevisiae (yeast) cell was used for the model in this research. Cells were manipulated under 10 Vpp at 100 kHz ~ 1 MkHz in 5 uS/cm artificial buffer solution. Many important parameters were characterized in the experiment including illumination of light source, photoconductive performance of amorphous silicon, chip temperature, cell seeding density and cell viability. This novel technique would promote the study of basic cell biology and biotechnology.