ANALYST, vol.138, no.23, pp.7238-7245, 2013 (SCI-Expanded)
A general protocol to prepare surface molecularly imprinted polymer core-shell superparamagnetic Fe3O4 nanoparticles (Fe3O4@MIP SPNPs), using a surface-mediated RAFT polymerization approach, is described. Cholesterol-imprinted Fe3O4@ MIP SPNPs were obtained by oleic acid-stabilized Fe3O4 nanoparticles with a trithiocarbonate agent and subsequently by polymerizing thin molecularly imprinted layers composed of dimethylacrylamide and N, N '-methylene(bis) acrylamide units. The surface-mediated RAFT polymerization approach allows the synthesis of similar to 20 nm hybrid composite particles with a similar to 6 nm MIP shell, exhibiting superparamagnetic properties (saturation magnetization - 35.4 emu g(-1)) and specific molecular recognition of cholesterol. The Fe3O4@MIP SPNPs show the capability of rapid enriching and separating cholesterol (similar to 3.1% in weight) and are renewable and cyclically exploited due to their monodispersive and superparamagnetic features. Moreover, under optimal conditions, the Fe3O4@MIP SPNP recoveries of spiked human serum, milk, yolk and beef were 91.6%, 93.6%, 92.4% and 91.2%, respectively. Finally, the method of molecular imprinting on superparamagnetic particles can be extended to a wide range of applications for cell sorting, biomolecule enrichment and separation, and drug delivery.