Improvement of single circulating tumor cells isolation with sievewell slides

Background Cell loss during cell labelling is a challenge when using pre-enrichment technologies not exploiting magnetic force, such as microfluidic systems e.g. the Parsortix^® system (Angle, UK). Although 95%-99.95% ‘contaminating’ red and white blood cells (WBC) can be removed with Parsortix, the remaining numbers of WBCs are still impeding single CTC isolation.

We aimed to implement direct labeling of single CTCs on different microwell chips in combination with micromanipulation in order to reduce cell loss due to handling.

Methods First, microwell slides with different sizes and geometries of the wells were generated with ALS (Germany) or purchased (sievewell, TOK, Japan). Breast cancer cell lines were used to test seeding, in situ labelling and micromanipulation efficacies. The following parameters were determined a) cell seeding rate (% of cells captured in wells); b) on-chip staining recovery rate; c) cell picking success rate. In addition d) cell purity rate was monitored in flat bottom PCR tubes. Second, further validation experiments were done with CTCs of an index breast cancer patient.

Result The best cell seeding rates were observed with 30µm micro wells. Best efficacies were obtained with the 20µmsievewell with an on-chip staining recovery rate of up to 97% and picking success rates and purity rates of almost 100%. Picking of the CTCs from sievewell chips with CellCelector DX system was most efficient with 20µm capillaries.

Conclusion Microwells such as the sievewell with 370k cavities in combination with micromanipulation system can improve the efficacy of CTCs detection and isolation.

Publication History

Article published online:
07 October 2020