An optical method is used to study the diffusion in the gels. This method allows a real-time visualization of the introduced impurities spreading in gels. The decomposition of the spectrum of the passing radiation in the optical range allows one to get more information not only about the nature of the diffusion distribution of the considered impurities, but also on the state of the gel itself. This paper presents results of temporal dynamics of transparency spectrum evolution during the formation of gel from silicic acid, when there are added nano-particles of silver in the media. The diffusion these nano-particles in the true gel and the diffusion of KMnO4 (given the molecular homogeneous solution with water) in the silica gel containing silver nano-particles are studied. Experimentally it is found that the presence of nano-partiles delays the shift of the wave length of the spectrum maximum of the transparency to the red range compare to true gel of silicic acid. This demonstrates that the velocity of gel formation decreases with the increase of concentration of nano-particles. At the same time the scattering light in green range of spectrum considerably increases, showing the change of the internal structure of the dispersion media. The fundamental differences in the diffusion velocity in gels between true solutions and solutions containing nano-particles are shown. A physical explanation is suggested for this phenomenon. It is observed experimentally that the diffusion of water solution of KMnO4 in the gel of silicic acid containing nano-particles of silver is about the same velocity that in true gel. The obtained results could be applied for the development of a model system, which can be used for verification of the efficiency of the delivery to cells of necessary preparations in order to control their metabolism during the cells growing in bio-reactors formed 3D printing.
