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 purifi-
cation 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 heterolo-
gously 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.