Traceable Impedance-Based Dispensing and Cloning of Living Single Cells

Generation of Monoclonal Chinese Hamster Ovary Cell Lines Using DISPENCELL-S3

Single-cell isolation is a key step in the manufacturing of therapeutic proteins, which relies on the development of monoclonal cell lines. It increases production safety and consistency. It also ensures higher manufacturing performances thanks to the selection of the rare clonally derived cell lines with optimal growth and production capacities. DISPENCELL-S3 is a small format single-cell dispenser whose technology is based on impedance spectroscopy. Here, we provide a detailed protocol for generating Chinese hamster ovary (CHO) monoclonal cell lines using DISPENCELL-S3. Production and characterization of an adequate cell sample for single-cell isolation, as well as the optimization of the DISPENCELL-S3 dispensing parameters are described. Monoclonal outgrowth assessment and the use of the recorded impedance signal as evidence of clonality are also outlined.

Impedance-Based Single-Cell Pipetting

Many biological methods are based on single-cell isolation. In single-cell line development, the gold standard involves the dilution of cells by means of a pipet. This process is time-consuming as it is repeated over several weeks to ensure clonality. Here, we report the modeling, designing, and testing of a disposable pipet tip integrating a cell sensor based on the Coulter principle. We investigate, test, and discuss the effects of design parameters on the sensor performances with an analytical model. We also describe a system that enables the dispensing of single cells using an instrumented pipet coupled with the sensing tip. Most importantly, this system allows the recording of an impedance trace to be used as proof of single-cell isolation. We assess the performances of the system with beads and cells. Finally, we show that the electrical detection has no effect on cell viability.