13 Smart polymers for bioseparation and other biotechnological applications

Abstract: The progress in development of a number of novel products using recombinant DNA technology and cell culturing, plus the demands for high product yield whilst preserving biological activity, require novel approaches for fast and cost-effective isolation and/or purification processes. Smart polymers (SPs) with their ability to undergo considerable changes in response to external stimuli make possible the development of novel technologies for isolation and purification. In this chapter the main applications of SPs in biotechnology and, in particular, in bioseparation, are discussed. Affinity precipitation, two-phase polymer separation, using SP membranes and SP chromatographic carriers are overviewed with a presentation of recent developments and discussion of future perspectives in these areas. Application of SP as catalysts is also discussed

Analysis of Polymer Grafted Inside The Porous Hydrogel Using Confocal Laser Scanning Microscopy

Graft polymerization of glycidyl methacrylate onto the pore surface of polyacrylamide macroporous gel was implemented in DMSO-aqueous solution using diperiodatocuprate(III) complexes as an initiator. The grafting densities up to 410% were achieved. The graft polymerization was confirmed by gravimetrical methods and FTIR. The graft polymerization of polymer inside the pores of the macroporous gel resulted in increased flow resistance through the gel matrix. The distribution of grafted polymer on the gel pore surface material was studied by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). CLSM is an alternative method for studying morphology of gel surface with grafted polymer having the advantages over the SEM allowing to investigate the distribution of grafted polymer inside the hydrogel in a native hydrated state. The microscopic techniques demonstrated uneven distribution of the grafted polymer inside the gel pores as a result of initiating the graft polymerization by insoluble initiator deposited on the pore surface.WoSScopu

Biomimetic macroporous hydrogels: protein ligand distribution and cell response to the ligand architecture in the scaffold

Macroporous hydrogels (MHs), cryogels, are a new type of biomaterials for tissue engineering that can be produced from any natural or synthetic polymer that forms a gel. Synthetic MHs are rendered bioactive by surface or bulk modifications with extracellular matrix components. In this study, cell response to the architecture of protein ligands, bovine type-I collagen (CG) and human fibrinogen (Fg), immobilised using different methods on poly(2-hydroxyethyl methacrylate) (pHEMA) macroporous hydrogels (MHs) was analysed. Bulk modification was performed by cross-linking cryo-co-polymerisation of HEMA and poly(ethylene glycol) diacrylate (PEGA) in the presence of proteins (CG/ pHEMA and Fg/pHEMA MHs). The polymer surface was modified by covalent immobilisation of the proteins to the active epoxy (ep) groups present on pHEMA after hydrogel fabrication (CG-epHEMA and Fg-epHEMA MHs). The concentration of proteins in protein/pHEMA and protein-epHEMA MHs was 80-85 and 130-140 mu g/ml hydrogel, respectively. It was demonstrated by immunostaining and confocal laser scanning microscopy that bulk modification resulted in spreading of CG in the polymer matrix and spot-like distribution of Fg. On the contrary, surface modification resulted in spot-like distribution of CG and uniform spreading of Fg, which evenly coated the surface. Proliferation rate of fibroblasts was higher on MHs with even distribution of the ligands, i.e., on Fg-epHEMA and CG/ pHEMA. After 30 days of growth, fibroblasts formed several monolayers and deposited extracellular matrix filling the pores of these MHs. The best result in terms of cell proliferation was obtained on Fg-epHEMA. The ligands displayed on surface of these scaffolds were in native conformation, while in bulk-modified CG/ pHEMA MHs most of the proteins were buried inside the polymer matrix and were less accessible for interactions with specific antibodies and cells. The method used for MH modification with bioligands strongly affects spatial distribution, density and conformation of the ligand on the scaffold surface, which, in turn, influence cell-surface interactions. The optimal type of modification varies depending on intrinsic properties of proteins and MHs. (C) Koninklijke Brill NV, Leiden, 200

IDENTIFICATION OF A (1B)1R SUBSTITUTION AND 1BL.1RS TRANSLOCATION IN WINTER WHEAT INTROGRESSION LINES BY CYTOGENETIC AND MOLECULAR METHODS

The (1B) 1R wheat-rye chromosome substitution and 1BL.1RS translocation have been identified in original introgression stocks using cytological and molecular marker analysis. The pairing between short arms of chromosomes 1BL.1RS and bread wheat chromosome 1B is observed at a very low frequency (in 0,2–0,3 % of pollen mother cells). The translocation stocks are resistant to leaf and stem rusts, and the substitution stocks are susceptible because of the different origins of the chromosomes 1R involved in the translocation or substitution. The Hg1 gene for glume hairiness, inherited from cv. Hostianum 237, has been detected in some introgression stocks. Several stocks show hairiness on the leaf upper surface, lower surface and leaf margin. The character, probably originating from Ae. tauschii, was inherited from the synthetic wheat T. timopheevii Zhuk./Aegilops tauschii Coss