Surface modification of chromatography adsorbents by low temperature low pressure plasma

In situ modification of chromatography adsorbents using cold atmospheric pressure plasmas

“…This point is beautifully highlighted by the unique separation challenges posed by "biological nanoplexes," a rapidly growing and diverse product grouping characterized by large physical size, fragility, complex surfaces "plus" chemical similarity to smaller contaminating macromolecular components. 5 These properties prohibit the efficient manufacture of nanoplexes using routes and chromatographic materials established for therapeutic human proteins of much smaller dimensions. [6][7][8] For example, whilst ion exchange chromatography is extensively used for the commercial scale purification of antibiotics and protein-based drugs, its application for biological nanoplexes (e.g., naked plasmid DNA, viral vectors, virus-like particles, mega-molecular vaccines, megaprotein complexes, IgMs) is far less attractive.…”

“…[8][9][10][11] New types of beaded chromatography adsorbents featuring two or more distinct functional regions spatially separated from one another within the same support bead have been the subject of a handful of research reports since 2002; 5,[12][13][14][15][16][17] the most promising of these describing the manufacture and testing of bi-layered bi-functional supports comprising ion exchange (IEC) functionalized cores surmounted by outer size excluding (SEC) layers. 5,[13][14][15] The main attraction of the bi-layered SEC-IEC support architecture ( Fig. 1(b)) is that it enables efficient separation of certain nanoplex bio-products (e.g., plasmid DNA) from smaller, but chemically very similar "problem" contaminants (protein, RNA) in a "one column-one bead" chromatography process combining size exclusion and ion exchange principles.…”

“…1(a) remains effectively unchanged. 5 As a result, few commercially available chromatographic materials tailored to the separation of many newer increasingly complex products exist at the present time. This point is beautifully highlighted by the unique separation challenges posed by "biological nanoplexes," a rapidly growing and diverse product grouping characterized by large physical size, fragility, complex surfaces "plus" chemical similarity to smaller contaminating macromolecular components.…”

“…1(b)) is that it enables efficient separation of certain nanoplex bio-products (e.g., plasmid DNA) from smaller, but chemically very similar "problem" contaminants (protein, RNA) in a "one column-one bead" chromatography process combining size exclusion and ion exchange principles. 5,13,14 The ideal bi-layered SEC-IEC support should possess inert mechanically reliable "non-stick" exteriors or barriers, that are freely accessible to smaller components (proteins, RNA), but not larger entities, such as long chain nucleic acids, cell debris fragments, nanoplexes, etc., and in order not to compromise mass transport and sorption properties, they must also be very thin, i.e., ideally <1 lm. 5,18 To date, these criteria have not been met.…”

“…5,13,14 The ideal bi-layered SEC-IEC support should possess inert mechanically reliable "non-stick" exteriors or barriers, that are freely accessible to smaller components (proteins, RNA), but not larger entities, such as long chain nucleic acids, cell debris fragments, nanoplexes, etc., and in order not to compromise mass transport and sorption properties, they must also be very thin, i.e., ideally <1 lm. 5,18 To date, these criteria have not been met. This letter details the in situ generation of atmospheric pressure plasma within an aqueous solution of "soft" porous hydrogel chromatography adsorbents; the reactive oxygen species (ROS) produced in the plasma are transported to the chromatography beads via gas bubbles and are shown to effectively remove surface functionality while leaving core functionality intact.…”