Particulate/cell separations using macroporous monolithic matrices

Particle-based stationary phases have been used in chromatographic techniques such as high-pressure liquid chromatography (HPLC), anion-exchange chromatography, and capillary liquid chromatography (CLC). Despite high stability and load-bearing capacity, a large void volume between the particles and high mass transfer resistance in flow of large macromolecules makes them inappropriate in separation processes (Bisjak et al. 2005, Podgornik and Strancar 2005, Unger et al. 2008). These limitations can be overcome by the use of monolithic stationary phases based on silica or polymers. Polymeric monoliths are generally made of synthetic, natural organic polymers, or a combination of natural and synthetic polymers. Polymer macroporous monoliths can be easily prepared by in situ polymerization of monomers with suitable cross-linkers directly in chromatographic units. The porosity in these monoliths can be obtained by the use of porogens and precise control of cross-linker or other reaction conditions. The liquid is forced to flow through these monolith pores with minimum mass transfer resistance. The convective flow between these pores enables fast separation of large molecules unlike high mass transfer resistance in particulate stationary phases (Holdsvendova et al. 2007). Ease in synthesis, fast separation, and efficient performance of these monolith matrices make them better than conventional stationary phases. Moreover, surface modifications and coupling of ligands are other advantages over conventional matrices.