Composite Microfiltration Membranes Imprinted with cAMP

Abstract

Composite microfiltration membranes covered with a thin layer of molecularly imprinted polymer (MIP) selective to adenosine 3¢:5¢-cyclic monophosphate (cAMP) were obtained and their separation properties were studied. MIP layers were prepared using photoinitiated copolymerization of dimethylaminoethyl methacrylate (DMAEM) as a functional monomer and trimethylopropane trimethacrylate (TRIM) as a crosslinker in the presence of cAMP as template in ethanol/water mixture. Blank membranes were prepared under the same conditions, but without cAMP. It was found out that pH of aqueous solution of the template has an effect on the binding of cAMP with MIP membranes. It was concluded that the ability of MIP membranes to bind cAMP is a result of both ionic interactions between charged dimethylamino groups of polymer matrix and the phosphorous residue of cAMP molecule and the specific shape of recognizing sites. These sites are complementary to cAMP in terms of three dimensional shape as well as correct position of functional groups involved in the template binding. This paper shows that the binding capability of MIP membranes can be adjusted by varying the values of degree of modification (DM). Atomic Force Microscopy (AFM) and Scanning Force Microscopy (SEM) were used to visualise surfaces and cross sections of membranes to gain better understanding in the analysis of MIP layer deposited on membranes.