1 Department of Biology, Concordia University, 7141 Sherbrooke Street West, Montréal, Québec H4B 1R6, Canada.
2 Centre for Applied Synthetic Biology, Concordia University, 7141 Sherbrooke Street West, Montréal, Québec H4B 1R6, Canada.
3 Department of Electrical and Computer Engineering, Concordia University, 1455 de Maisonneuve Blvd. West, Montréal, Québec H3G 1M8, Canada.

Viral-based systems are a popular delivery method for introducing exogenous genetic material into mammalian cells. Unfortunately, the preparation of lentiviruses containing the machinery to edit the cells is labor-intensive, with steps requiring optimization and sensitive handling. To mitigate these challenges, we introduce the first microfluidic method that integrates lentiviral generation, packaging, and transduction. The new method allows the production of viral titers between 10⁶ and 10⁷ (similar to macroscale production) and high transduction efficiency for hard-to-transfect cell lines. We extend the technique for gene editing applications and show how this technique can be used to knock out and knock down estrogen receptor gene-a gene prominently responsible for 70% of breast cancer cases. This new technique is automated with multiplexing capabilities, which have the potential to standardize the methods for viral-based genome engineering.