SPHEROID SORTING

Three-dimensional (3D) cell cultures are progressively used for research in regenerative medicine, tissue engineering, drug discovery, toxicity testing, drug discovery and cancer research. They are preferred over two-dimensional cell cultures or single cells, because they can imitate in vivo architecture of natural organs and tissues. Cultured spheroids can be heterogenous in size so it is necessary to isolate them into a uniformly sized population for downstream applications, such as drug assays.

Fig. 1. (a) Sorting of 100 µm spheroids using On-chip Sort. (b) Growth of 45 µm sorted spheroids over time. Red arrows indicate cell cluster.

When sorting spheroids on conventional sorters, they can be damaged and deformed due to high shear stress and high-speed collision, and in many cases, spheroids do not even pass through the nozzle. On the other hand, On-chip Sort can perform damage-free sorting of spheroids up to 150 µm in diameter. Fig. 1a shows sorting of 100 µm spheroids from a heterogeneous population of spheroids using On-chip Sort. Smaller spheroids (45 µm) were also sorted using On-chip Sort and cultured over several days. The cultured spheroids tripled in size on Day 10 (Fig. 1b). These results suggest that On-chip Sort is not only capable of sorting spheroids, but also capable of keeping spheroids viable after sorting.