Time Sequential Single-Cell Patterning with High Efficiency and High Density

Abstract

Single-cell capture plays an important role in single-cell manipulation and analysis. This paper presents a microfluidic device for deterministic single-cell trapping based on the hydrodynamic trapping mechanism. The device is composed of an S-shaped loop channel and thousands of aligned trap units. This arrayed structure enables each row of the device to be treated equally and independently, as it has row periodicity. A theoretical model was established and a simulation was conducted to optimize the key geometric parameters, and the performance was evaluated by conducting experiments on MCF-7 and Jurkat cells. The results showed improvements in single-cell trapping ability, including loading efficiency, capture speed, and the density of the patterned cells. The optimized device can achieve a capture efficiency of up to 100% and single-cell capture efficiency of up to 95%. This device offers 200 trap units in an area of 1 mm2, which enables 100 single cells to be observed simultaneously using a microscope with a 20× objective lens. One thousand cells can be trapped sequentially within 2 min; this is faster than the values obtained with previously reported devices. Furthermore, the cells can also be recovered by reversely infusing solutions. The structure can be easily extended to a large scale, and a patterned array with 32,000 trap sites was accomplished on a single chip. This device can be a powerful tool for high-throughput single-cell analysis, cell heterogeneity investigation, and drug screening.

Chemical Analysis of Single Cells and Organelles

“…The device presented by Liu et al consisted of a serpentine PDMS channel lined with geometrical traps. 179 Due to a gap in each trap, cells are hydrodynamically manipulated into the confinement. When a trap is occupied, the next cell will not be forced into this trap but progress to the next empty trap.…”

Biosensors Based on Mechanical and Electrical Detection Techniques

“…Figure 14 demonstrates the construction of the system used by Shih et al Such a system is highly interesting, and could be very useful for future diagnostics by separating out the population of interest [ 172 ]. More recently, true single cell separation has been achieved by Liu et al who have effectively employed a microfluidic channel to sort a single cell suspension into individual wells [ 173 ]. If this were to be employed with electrodes embedded within the wells (as previously demonstrated [ 174 ]), it would permit more detailed information to be achieved with relative ease.…”

Topology Optimization of Passive Cell Traps

“…The flow cell capture method uses fluid flow to guide cells into the trap position and captures the cells at a relatively fixed position for detection. The main flow direction can be the same as the capture direction [ 23 ] or perpendicular [ 24 , 25 ]. The capture efficiency mainly depends on the flow resistance of the whole basin and the difference in flow resistance between the capture channel and the bypass flow channel.…”