In this work, the encapsulation of the transition metal complexes cis-Pt(NH3)(2)Cl-2, Ru(bpy)(3)(2+), and Ru(phen)(3)(2+) within layers of hydroxyapatite on a porous Si/Si substrate are described. These;specific complexes were selected as a consequence of their biological activity (cis-Pt(NH3)(2)Cl-2) or polynucleotide binding ability (Ru(bpy)(3)(2+) and Ru(phen)(3)(2+)). The complex-doped hydroxyapatite/porous Si/Si materials have been characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, secondary ion mass spectrometry, and photoluminescence spectroscopy. It is possible to exercise some control of the release of a given complex into the surrounding medium through thermal heating of the complex-doped hydroxyapatite/porous Si/Si structure.