ELECTROSPUN NANOFIBERS FOR PROTEIN ADSORPTION

Biopharmaceutical therapeutics (i.e., recombinant proteins, monoclonal antibodies, viral vaccines, and plasmid DNA) are quickly becoming major contributors to the fifights against life-threatening and debilitating disorders. Prior to 1997 only 6% of approvals by the US Food and Drug Administration (FDA) for new therapies were for biopharmaceuticals. However, between 1997 and 2013 that number grew to 26%, and as of this writing there are thousands of potential drug products of biological origin in clinical development (Reichert, 2004). As encouraging as these fifigures are, the biopharmaceutical industry is facing enormous pressures from the government and the public to improve the quality of therapeutics and increase the speed to market, while reducing the costs of production (Sundberg, 2003). These demands are particularly relevant to the downstream purifification of biological therapies because not only are the separation operations responsible for producing a safe product that meets purity guidelines established by the FDA, but also the economic modeling of processes has shown that a signifificant percentage (i.e., up to 80%) of the overall manufacturing costs is incurred during downstream purifification (Roque et al., 2004). Conventional separation technologies, including packed-bed adsorption and chromatography, membrane fifiltration, and precipitation and crystallization, have been used for decades for the separation and purifification of biologically valuable products. While these techniques have provided acceptable results, they are often ineffificient in terms of material and time requirements (Lightfoot and Moscariello, 2004). With these challenges also come opportunities to improve the separation and purifification processes of biopharmaceutical therapeutics; herein, new separation and purifification media utilizing electrospun cellulose and carbon nanofifibers as the supports for chemical ligands within membrane adsorbers are reported.

The workhorse for industrial separation and purifification processes is selective adsorption and elution of the target molecules within a packed bed of porous resin beads. The operation provides reasonably good purifification factors, is reliably scaled between development and manufacturing sizes, and can be easily validated for commercial production (Levison, 2003). Unfortunately, this process also suffers from several major limitations. First, the operational flflow rates used during processing must be kept relatively low to maintain acceptable pressure limits, and this often requires reducing the flflow rate during processing owing to pressure increases. Similarly, to achieve high binding levels of the target molecules, in terms of bound product per volume of resin, very long residence times are required (again necessitating slow flflow rates or cumbersome packing arrangements). These capacity limitations are primarily due to very slow intraparticle diffusion of the relatively large biomolecules to access available binding sites deep within the porous resin beads. Finally, concerns persist regarding the potential for flflow channeling and poor dispersion within the packed bed, which lead to ineffificient use of expensive resin (Ghosh, 2002; Charcosset, 1998).

Paper link：https://www.sciencedirect.com/book/9780323512701/electrospinning-nanofabrication-and-applications