Hydroxyapatite surface silylation with organosilane derivatives (H(3)CObSiR, R being the corresponding organic moieties -CH2CH2CH2NH,), -CH2CH2CH2NHCH2CH2NH2, and -CH2CH2CH2NHCH2CH2NHCH2CH2NH2, was carried out to yield organofunctionalized nanomaterials, named HApR1, HApR2. and HApR3, respectively. The products were characterized by elemental analysis, infrared spectroscopy, X-ray diffraction. thermogravimetry, and P-31 and C-13 NMR in the solid state. The amounts of groups grafted onto surfaces were 0.75 +/- 0.05, 2.35 +/- 0.14, and 2.48 +/- 10.18 mmol g(-1) for HApRx (x = 1,2, 3) surfaces, respectively. Linear correlations between elemental analysis, mass loss, 31 p chemical shift data, and the characteristics of the chain of each alkoxysilane were observed. The organic basic centers distributed onto the external surface have the ability to adsorb divalent copper and cobalt cations from aqueous solution. The degree of adsorption obtained from batchwise processes showed the best performance of these synthesized nanomaterials when compared with the pristine hydroxyapatite. (c) 2006 Elsevier Inc. All rights reserved.