Correlation and cross-linking effects in imprinting sites for divalent adsorption in gels

We examine a method to mimic active sites in proteins by chemical imprinting of p-valent templates in heteropolymer gels. Previous studies have confirmed successful formation of sites by adsorption of targets with p >= 2 contacts. We investigate the recovery of sites with p = 2 imprinted by lead methacrylate Pb(MAAc)(2) (placing two carboxyl groups in close proximity). The improved binding ability of gels with more crosslinks, and the relative insensitivity to changes in gel volume contradict simple theory. We conclude that adsorber pairs are predominantly located on the same polymer chain, posing a challenge to mimicking protein-like function.