Polymeric devices containing imprinted nanospheres: a novel approach to improve recognition in water for clinical uses

Molecular imprinting permits to introduce in synthetic macromolecules molecular information through the polymerisation of a monomer in the presence of a stamp molecule (template): the solution polymerisation is receiving, in the last 5 years, increasing attention due to the effective selective behaviour of produced materials obtained in the shape of micro or nanoparticles. The frontier of this family of materials is the improvement of recognition performances in aqueous environment. Our work started from the idea to increase binding and selective behaviour of cross-linked poly(methylmethacrylate-co-methacrylic acid) nanospheres in aqueous media through an innovative approach: imprinted nanospheres are loaded in the bulk or on the surface of poly(methylmethacrylate-co-acrylic acid) membranes. In this way, enhanced recognition performances of acrylic membranes can be expected, taking advantage of recognition characteristics of imprinted nanospheres. Recognition and binding behaviour of free and supported particles was compared, showing an increased recognition factor for loaded particles. Imprinted particles were able to keep-on 1.72 mg of theophylline and 4.12 mg of caffeine/g of polymer in physiological solution and the recognition factors for each template resulted to be higher for supported particles, in particular in the case of theophylline (passing from 1.02 to 6.32), suggesting the creation of a preferred microenvironment for the rebinding of nanoparticles.