Achieving Fully Continuous End-to-End Processing

The current “continuous” downstream is a complex sequence of batch operations, almost a slight-of-hand continuous process that cannot take advantage of most of the value of truly continuous processes. While the current chromatography-based processes are sufficient to bring the cost of goods manufactured down by 40-60%, there is significant benefit from a truly continuous process. We have demonstrated the use of recombinant affinity nanoparticles and complexes in a dialysis and tangential-flow filtration-based capture step. The development of the nanoparticles is challenging and we have tested over 100 nanoparticles evaluating expression, their ability to bind antibody, and their stability under acidic elution conditions. We believe many are economical enough to allow commercial use, though we have found many to have suboptimal stability at low pHs and that most of the high-pH constructs have significantly reduced capacity. Finally, we have found that the wide pore-size distribution on UF membranes have allowed 10% or more of the nanoparticle to pass through along with the antibody. We will discuss general methods we’ve used to quickly evaluate nanoparticles including small scale, ~1000kDa MWCO dialysis, and centrifugal dead-end ultrafiltration. We will also discuss associated analytical techniques including mass photometry, SEC, and native blue electrophoresis. The data we have generated allows us to be confident that these methods are worth continued effort. Truly continuous processing allows the reuse of solutions from a cleaner downstream to a dirtier upstream. This reuse of solution, and the continuous nature of the process, should decrease cost of goods beyond the current ICB processes while increasing the level of sustainability.