Improvement of single circulating tumor cells isolation with CellCelector

Background and Aim:

The CellCelector system enables the isolation of single circulating tumor cells (CTCs) for comprehensive genomic analysis. However, although different technologies are used to pre-enrich CTCs, high numbers of contaminating white blood cells (WBCs) are still impeding single cell isolation.

We aimed to implement technical solutions to both issues in order to optimize and speed-up single cell micromanipulation.

Material and methods:

SKBR3 cells were spread onto PDMS nano well chips of different geometries. We tested nano wells with cavities ranging from 15 µm to 30 µm in diameter and determined a) the cell seeding rate (% of cells captured in nano wells); b) the cell picking success rate; c) the cell purity rate; and d) on chips staining recover rate. Deposition was verified by microscopic inspection with flat bottom tubes from two different providers.

Results:

Best cell seeding rates were observed with 30 µm nanowells, with 15 µm nanowells many cells were not captured. On-chip staining resulted in a recovery rate of 80%–90%, due to reduced cell loss during staining. Deposition control worked to 100% with 4titudes flat bottom tubes. A new adapter for CellCelector™ was designed and produced to execute this workflow on the microscope stage thereby also increasing the speed of micromanipulation by approx. 50% to 60%.

Conclusions:

We have improved single CTCs isolation with the CellCelector™ by implementing nano well chips for cell separation and flat bottom tubes to control cell deposition. Apart from the reduced processing time this will also reduce the costs caused by unsuccessful cell deposition.