Functional nano-hydroxyapatite for applications in conservation of stony monuments of cultural heritage

Abstract

Stony monuments have high artistic value and need continuously to be preserved from the damages of time, in particular from the detrimental effects of the weathering. One of the new environmentally-friendly (nano) materials for stone consolidation, particularly suitable for marble and calcareous (limestone, sandstone) artifacts, is Ca10(PO4)6(OH)2 hydroxyapatite (HAp), which shows a considerably lower dissolution rate and solubility compared to CaCO3 calcite, the building block of marble materials, especially in acidic environments, thus having been proposed for the protection of calcareous monuments against acidic rain corrosion. Promising results were obtained, but further optimization is necessary as the treated layer is often incomplete, cracked and/or porous. Many parameters have to be optimized to obtain a coherent and homogenous layer, and consequently to avoid the formation of metastable, soluble phases instead of HAp: the role of the pH of the starting solution; the effect of organic and inorganic additions, and in particular that of ethanol, that is reported to adsorb on calcite, hence possibly favoring the growth of the HAp layer. The formation of HAp nanoparticles and the applications on stony substrates were investigated by means of a multi-methodological approach, based on scanning electron microscopy, x-ray diffraction, small-and/or wide-angle x-ray scattering, Fourier-transform Infrared spectroscopy, completed by in situ measurements of laser-induced breakdown spectroscopy and acid attack preliminary test on stony substrates.

Imatinib-Functionalized Galactose Hydrogels Loaded with Nanohydroxyapatite as a Drug Delivery System for Osteosarcoma: In Vitro Studies

“…Moreover, the presence of the OH − in the structure was confirmed by the librational vibration of OH − groups at 633 cm −1. 32 The typical stretching band of the C−OH group of galactose (3,6anhydro-α-L-galacto-β-D-galactan) hydrogel is localized at the maximum position of 3296 cm −1 (blue space in Figure 1B). There are also visible other characteristic peaks of galactose, at 1071 cm −1 (vibration of C−O−C bridge of glycosidic linkage, green space, Figure 1B) and 931 cm −1 (vibration of C−O−C bridge of 3,6-anhydrogalactose unit, orange space, Figure 1B).…”

Synthesis of a new potassium-substituted lead fluorapatite and its structural characterization

“…4 These applications range from biological applications 5,6 up to wider uses. For example, in the field of optics technology, they can serve as phosphors for fluorescent lamps, 7,8 as sieves for water remediation, 9 as coating materials for cultural heritage protection materials, 10 etc.…”