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 cross-links, 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.