Cell sorting with combined optical tweezers and microfluidic chip technologies

Sorting of specific target cells is an important process in biotechnological research and clinical medicine. This paper proposes a methodology that integrates optical tweezers and microfluidic chip technologies to realize the automatic cell sorting in a continuous flow environment. In the proposed system, cells are driven through the region of interest, and the digital image processing technique is utilized to recognize the target cells. The optical tweezers are used to move the cells selected by image processing to the desired area. In order to move the target cells to the collection reservoir more quickly and reduce the cell-cell interactions (e.g., clustering or jamming), the motion of optical tweezers is further investigated. The relationship between the laser power and the cell maximal escape velocity has been studied to achieve the robust cell sorting with lower power. The idea of multi-trap parallel processing is proposed to achieve high throughput without losing the purity. Utilizing the proposed cell sorter, we can collect rare cells from a sample of primary tissue without expansion, with less damage and higher accuracy.