Selective recovery of histidine-containing dipeptides based on metal affinity interactions using chemically modified dextran in combination with ultrafiltration

Cellulose aerogel regenerated from ionic liquid solution for immobilized metal affinity adsorption

Surface morphology of cellulosic adsorbents is expected to influence the adsorption behavior of biomacromolecules. In the present study, cellulose aerogel regenerated from ionic liquid solution was prepared for use as a polymer support for protein adsorption. Iminodiacetic acid groups were introduced to the aerogel for immobilized metal affinity adsorption of proteins. A Cu(II)-immobilized iminodiacetic acid cellulose aerogel (Cu(II)-IDA-CA), which has a large specific surface area, showed a higher adsorption capacity than Cu(II)-immobilized iminodiacetic acid bacterial cellulose (Cu(II)-IDA-BC) and Cu(II)-immobilized iminodiacetic acid plant cellulose (Cu(II)-IDA-PC). In contrast, the Cu(II)-immobilized cellulosic adsorbents showed similar adsorption capacities for smaller amino acid and peptides. The results show that cellulose aerogels are useful as polymer supports with high protein adsorption capacities.

Production of novel polymer monolithic columns, with stationary phase gradients, using cyclic olefin co-polymer (COC) optical filters

Polymer monolithic columns with controlled surface ligand density, providing stationary phase gradients within monolithic capillary columns, have been developed using photo-grafting through optical filters. Utilising commercially available cyclic olefin co-polymer (COC) films, the production of an optical filter capable of attenuating UV irradiation, in a tailored manner, was investigated. This novel optical filter was successfully applied to the surface modification of poly(BuMA-co-EDMA) monolithic columns in a multi-step grafting procedure. Fabricated columns were subjected to scanning capacitively coupled contactless conductivity (sC(4)D), to determine the distribution of the grafted functional groups, axially along the column. Further modification to produce a chelating stationary phase gradient of iminodiacetic acid (IDA) was demonstrated. To demonstrate the distribution of the IDA sites, a metal cation (Cu(2+)) was complexed to the IDA forming a chelate. Upon the formation of a complex of IDA with Cu(2+), an overall drop in conductive response was observed. The COC optical filter was also used in the fabrication of a grafted gradient of strong cation exchanger (SCX), sulphopropyl methacrylate (SPM) upon a polymer monolith, demonstrating the broader applicability of such a filter.