Generation of Cellular Biofactories for Scalable Production of Surface-Engineered Extracellular Vesicles via CRISPR...

Extracellular vesicles (EVs) are versatile biological nanoparticles with applications in therapeutics, diagnostics, and biotechnology. Current production methods using transient transfection or chemical conjugation suffer from high variability, limited scalability, and heterogeneous EV populations. Here, we developed CRISPR-Cas9 engineered HEK293T cell lines with stable integration of mCherry-C1C2 fusion proteins at the AAVS1 locus for continuous production of surface-modified EVs. The engineered cell lines demonstrated significantly higher surface display efficiency compared to transient transfection, with reduced batch-to-batch variability. EVs maintained native characteristics including size distribution (120-130 nm) and marker expression while showing efficient cellular uptake. The platform maintained consistent production of uniformly modified EVs with stable transgene expression over at least 25 passages (~3 months), eliminating the need for repeated transfections and reducing batch-to-batch variability inherent to transient expression systems.