Gold- and silver-containing bionanocomposites based on humic substances extracted from coals

摘要

Thermal stability, structural peculiarities and thermal destruction of functional groups of the matrix, which are responsible for the stabilization of the nanosystems, of the gold-and silver-containing medicinally important water-soluble nanocomposites synthesized from therapeutic humic substances, isolated from brown coal of Baga Nuur field of Mongolian sources, have been studied. A crucial problem in biomedical and engineering application of the silver- and gold-containing nanocomposites is their stability upon heating, for example, during sterilization at high temperatures in medicine or laser action, which can heat a system, in plasmon technologies. All compounds have been investigated by complex modern physical-chemical methods (electron paramagnetic resonance and infrared spectroscopies, X-ray diffraction analysis, transmission electron microscopy and others). Thermal analysis of Ag-0 and Au-0 nanocomposites on the basis of humic matrices, as well as the initial humic substance, has been carried out. It is shown that the thermal decomposition of the nanocomposites depends on the nature of the metal. It is found that stable zero-valent nanoparticles of noble metals with an average particle size of 6-17 nm are formed in a natural matrix. The nanocomposites obtained are aggregatively stable for a long time, preserving their properties intact, that is extremely important for promising medicinal substances.