ABSTRACT
Molecularly imprinted polymers (MIPs) are highly crosslinked polymers that can be readily tailored with a⁄nity and selectivity for a molecule of interest [1^3]. MIPs compare favorably with other synthetic molecular recognition systems such as engineered antibodies and molecule receptors. For these reasons, MIPs have demonstrated utility in a wide array of applications requiring molecular recognition including separations [4], catalysis [5], and sensing [6,7]. Despite their versatility, MIPs have been limited in their practical utility due to their poor overall binding characteristics. A major contributor to this problem has been the heterogeneity of binding sites in MIPs. Ideally, the imprinting process would generate homogenous polymers inwhich all the siteswere identical with highbinding a⁄nities like enzymes and antibodies (Fig. 1). The imprinting process, however, typically proceeds with low ¢delity, generating binding sites that vary widely in shape, size, and binding a⁄nity.This binding site heterogeneity is detrimental to the utility ofMIPs in almost every application. For example, binding site heterogeneity leads to severe peak asymmetry and tailing that hinders the use ofMIPs in chromatographic applications [8]. The heterogeneous distribution is also weighted toward the low a⁄nity low selectivity sites and these low a⁄nity sites dominate the binding properties of MIPs, yielding low overall binding constants [9,10].
