Production of nano-protein particles in living cells

The escalating demand for therapeutic proteins calls for advanced biomanufacturing and formulation strategies to ensure efficient production and timely supply. Productions of therapeutic proteins, as well as many other proteins, require high purity and stability. However, the manufacturing process is bottlenecked by the purification process. We have established a novel platform leveraging the capabilities of living E. coli cells as cell factory, for efficient synthesis (protein expression) and easy separation (protein particle formation) of a model protein, Red Fluorescent Protein (mRFP). With the designed plasmid, the target protein (mRFP) was heterologously expressed inside cells, and directed to form protein particles, and the red fluorescence of these particles proved their correct folding and bioavailability. Target protein production was validated through SDS-PAGE and fluorescent microscopy. The cells with protein particles and the isolated protein particles were characterized by SEM, optical and fluorescent microscopic. The new cell factory technology developed for mRFP production has exhibited broad potential in advancing biomanufacturing, which can be further developed to enable the efficient bioproduction of other therapeutic proteins and peptides.