Micro- and Nanotechnologies
Technology development for micro and nanofluidic devices
Developing new engineered clonal cell lines is essential for loss-of-function studies, investigating protein function and unraveling signaling cascades and metabolic pathways. The current mammalian cell engineering pipeline of DNA delivery, selection, screening or sorting, and single-cell clonal expansion remains challenging and heavily relies on multiple expensive automated systems like a flow cytometer, cell sorters and colony pickers to increase experimental success.
Our group has shown the use of digital microfluidics for automating gene-editing procedures (Sinha et al.,2018), yet these devices still lack the ability to select for successful edits or sort cells out into single clones.
Hybrid microfluidics combine the digital and droplet microfluidic paradigms in one device (Ahmadi et al., 2019), with electrode lined channels that can introduce more control over droplets in channels. In this talk, I will present four key results: First, we developed a hybrid microfluidic method for deterministic single-cell encapsulation. I’ll introduce a single-cell trapping array that is capable to achieve near-perfect one-cell-per-droplet encapsulation. Second, I will present the droplet operations that can be performed on this device. This includes precise on-demand droplet operations including releasing, merging and keeping single-cell containing droplets. Which allows for dynamic assays of mammalian single cells, based on screening parameters that go beyond the traditional fluorescence based screening or sorting methods. All these operations, including encapsulation, can be easily performed with a graphical user interface. Third, I will describe the efficiency of cell trapping, cell encapsulation, droplet release and droplet keeping under different flow rates. Fourth, I will describe results that validate our platform for use in the mammalian cell engineering pipeline, using a breast cancer cell line (MCF-7) and a lung carcinoma cell line (NCI-H1299) as a model system. Specifically, I will show results related to encapsulation of a heterozygous and edited cell population and instant selection of transfected single-cells with subsequent generation of a clonal, isogenic edited cell line that could be expanded off chip.