According to ISI Web of Science (Thomsom Reuters) the review article "Molecular imprinting in cross-linked materials with the aid of molecular templates - a way towards artificial antibodies" by G. Wulff, published in Angewandte Chemie International Edition, 1995, 34, 1812-1832 (DOI: 10.1002/anie.199518121 ) has 1,804 citations.  This makes it the most highly cited MIP paper to date.

Other papers with over 1000 citations include:

Molecularly imprinted polymers and their use in biomimetic sensors, (2000), Haupt, K., Mosbach, K. Chemical Reviews, 100, 2495-2504. (DOI: 10.1021/cr990099w )  1,254 citations

and

Drug assay using antibody mimics made by molecular imprinting, (1993) Vlatakis, G., Andersson, L. I., Müller, R., Mosbach, K. Nature, 361, 645-647. (DOI: 10.1038/361645a0 )  1,128 citations

The paper in Nature, is, to my knowledge, the most cited research article in the area of molecularly imprinted polymers.  The numbers of citations are correct at the time of writing (4th July 2016).

Mike Whitcombe, SMI President