Molecularly imprinted polymeric nanoparticles decorated with Au NPs for highly sensitive and selective glucose detection

A new kind of designed water-compatible molecularly imprinted conductive nanoparticles was prepared by combining macromolecular self-assembly with molecularly imprinting technique. An amphiphilic random copolymer poly(DMA-co-EHA-co-HEA-co-St) containing imino groups and photocrosslinking units was synthesized through free radical copolymerization, which could self-assemble with template molecules (glucose) in aqueous solution to establish nanoparticles embedded with glucose. Meanwhile, AuCl4−, as precursor, was added to generate Au NPs in situ because of reducibility of protonated imino groups, leading to the formation of molecularly imprinted polymeric nanoparticles decorated with Au NPs (Au@MIPNs). By simply adjusting the pH value of the assembly solution, Au@MIPNs with different loading amount of Au NPs could be obtained. Electrodeposition was employed to fabricate a robust integration of MIP film with a transducer, then the film was photo-crosslinked by UV irradiation. After extraction of the template molecules, an MIP sensor modified with Au NPs (Au@MIP sensor) was successfully constructed. The presence of Au NPs greatly improved the conductivity of Au@MIP film and allowed direct electrical connection between the recognition cavities and the transducer, which enhanced the sensitivity of the sensor for templates detection. Effect of Au NPs amount on the performance of the Au@MIP sensor was also evaluated. The obtained Au@MIP sensor demonstrated acceptable selectivity and wider linear ranges (two linear ranges from 10−10 to 10−8 mol L−1 and 10−8 to 100 mol L−1 with a detection limit of 3×10−12 mol L−1) for glucose detection than MIP sensor without decoration of Au NPs.