Macroporous Gel Particles As Novel Sorbent Materials: Rational Design

Abstract

A novel design approach to form macroporous gels is presented. Macroporous gels (MGs), known as cryogels (or gels prepared at subzero temperatures), were prepared inside a protective plastic core (so-called, housing), thus making them resistant to shear forces at stirring. MGs are highly elastic polymeric materials with pore sizes up to 100 µm and spongelike morphology. Design of MGs inside a protective plastic core (defined as macroporous gel particles, MGPs) allows for expanding the potential applications of such polymeric materials, even to processes in well-stirred bioreactors. MGPs are resistant to attrition caused by continuous stirring at 400 rpm, while the MGs (prepared under the same conditions) were completely crushed within 1–2 h of stirring. MGPs with a different functionality were prepared and used in the model sorption experiments. Thus, polyacrylamide-based MGPs of different porosities and bearing metal-chelate ligand, iminodiacetate (IDA), were used for capture of Cu(II)-ions at low concentration from water. Because of the large size of interconnected pores in the MGPs, targets of different sizes (low molecular weight targets as Cu(II)-ions and particulate targets as yeast cells) can be captured on the MGPs (bearing specific ligands to the targets) from a complex mixture. The MGPs can be dried, stored in the dried state, and reswollen when required. The open permeable porous structure of MGPs and high stability at stirring together with ease of preparation make the MGPs a very attractive, novel, robust sorbent medium for different biotechnological applications.