Poly(hydroxyethyl methacrylate) (PHEMA) nanoparticles with an average size of 150 nm in diameter and with a poly-dispersity index of 1.171 were produced by a surfactant free emulsion polymerization. Specific surface area of the PHEMA nanoparticles was found to be 1779 m(2)/g. Reactive imidazole containing 3-(2-imidazoline-1-yl)propyl(triethoxysilane) (IMEO) was used as a pseudo-specific ligand. IMEO was attached covalently onto the nanoparticles. PHEMA-IMEO nanoparticles were used for the affinity binding of immunoglobulin-G (IgG) from human plasma. To evaluate the degree of IMEO loading, the PHEMA nanoparticles were subjected to Si analysis by using flame atomizer atomic absorption spectrometer and it was estimated as 64.5 mg/g of polymer. The nanoparticles were characterized by transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR). IgG binding onto the PHEMA nanoparticles was found to be 5.2 mg/g. Much higher binding values (up to 843 mg/g) were obtained for the PHEMA-IMEO nanoparticles. IgG could be repeatedly bound and eluted on PHEMA-IMEO nanoparticles without noticeable loss in the IgG binding capacity. (C) 2008 Elsevier B.V. All rights reserved.