MaxCyte’s proprietary flow electroporation technology has been successfully applied in ex vivo cell therapy (1) and drug discovery pipelines where reproducibility, efficiency and the need for increased cell numbers are critical. This technical paper discusses the merits of transient transfection using flow electroporation versus other recombinant expression approaches and its application in hit identification and lead optimization programs. Data are presented demonstrating the key features of the MaxCyte® STX™ Scalable Transfection System, including broad applicability, scalability, and the production of functionally relevant cells that enable its streamlined integration within cell-based assay methodologies. Case studies are presented for large-scale cellular GPCR screening and the functional characterization of multi-subunit voltage-gated ion channels.