Investigation of thiourea activated polyglutaraldehyde with bound ag(i) or pt(ii) as an alternative to avidin for immobilizing biotin conjugates

Pre-polymerized glutaraldehyde covalently linked to thiourea has been synthesized as a soluble polymer for immobilizing Ag(l) and Pt(II) and it has also been used for activating a polyacrylamide gel filtration media. The modified gel filtration media (Bio-Gel P-200) has a high capacity for\ Ag(I) (20 umol/ml) and Pt(II) (8 u,mol/ml) and has been shown to be stable and useful even in the presence of relatively high chloride (up to 1 M NaCl) and phosphate concentrations (0.25 M). The soluble polymer can have a Ag(I) capacity of between 2-11 mmol/g. Bio-Gel P-200 modified using glutaraldehyde/thiourea and in the Ag(I) and Pt(II) form selectively binds biotinylated BSA (b-BSA) over BSA. Using the Ag(I) form of the gel at pH 4.8 (0.05 M phosphate) only b-BSA binds and 30% can be eluted using 0.15 M NaCl, while no BSA binds to the column under these conditions. For the Pt(II) form of Bio-Gel P-200 at pH 4.8, none of the applied BSA binds to the modified resin while 40% of b-BSA does bind.