SAFETY OF NOTECHNOLOGIES
Last decades heightened interest to search and fabricate of various nano-structured technical materials, medical and biologic preparations and substances possessing unique physical, chemical, medical and biologic properties at the heart of which various nano-particles and high nano-technology exist. In this connection, today an attention of many researchers all over the world is concentrated on estimation of system’s, organs’s, cellular’s and subcellular’s effects of action of nano-materials on live systems, on definition of their safety for the person and his health at the direct usage of them in medicine, as well as by means of indirect contact with them during their industrial manufacturing. So, special vigilance in the manufacture sphere has to be caused by possible negative influence of nano-particles on health of workers on the sites connected with direct contact with nano-particles. Today there are not in the literature any data about what possible occupational diseases can trap such workers, about in what ways and by what means of medicine it is possible to diagnose them at early stages and about what are necessary additional to measure to decrease risks of development of such occupational diseases of workers at such enterprises, to avoid for workers a situation to get invalid, etc. Today there are not any official norms, maximum permissible levels of concentration of nano-perticles and nano-structured materials. There are not even the specialized techniques, a little bit scientifically-proved (not mentioning of standardized ones), on studying of their biological danger (safety). Accordingly, the statement and execution of scientific researches on studying of safety of nano-particles and nano-materials, on creation of methods of estimation of their biological danger is very important, actual and perspective.
Our Laboratory of medical and physical researches from the moment of its creation has started this study. The scientific review on the problem has been prepared and published (see our publications). Problems, ways and possible methods of their solutions which can be objectives of the research in the laboratory have been formulated. In 2009-2010 first pilot researches have been initiated and carried out in the laboratory on studying of negative influence of silver nano-particles (colloidal solutions of nano-particles) on small and young laboratory animals (white mice) at daily "per os" introduction of nanoparticles with potable water. Contrary to a number of known literary data we did not reveal any serious toxic action of silver nano-particles on white mice within a month of daily administration of nano-particles to mice in concentrations up to 100 mg/l. Two generations of posterity from the mice using nano-particles without visible defects of their birth and development are traced. It was not revealed also any both antimicrobial and bacteriostatic actions of a colloidal solution of silver nano-particles on cultures of golden staphylococcus (S.aureus 209 P) and an intestinal stick (E.coli 26941). The given research was spent together with the laboratory of microbiology at MONIKI, and it was shown that due to a low solubility of silver in water there are no chemical mechanisms of antibacterial action of silver nanoparticles. So, it is the myth. At the same time, for adult mice of comparable age with the average age of the industry workers (46-48 years), a certain toxic action of nanoparticles of silver was recorded. It means that for the professional pathology medicine the study needs to be conducted on animals of a middle and advanced age for whom protective forces of their organism are already reduced.
Now our study on safety of nanoparticles proceed with the use of nanoparticles of titanium dioxide, cerium, etc. We have observed the cardiotoxicity of gold nanoparticles. For silver nanoparticles together with the National Research Center "Kurchatov Institute" we found their penetration into the brain of laboratory animals and, apparently, for the first time in the world we have measured quantitative parameters of this penetration (see our paper here (PDF, 270K)). Therefore, today our research concentrates on the study of cognitive dysfunction in animals and their offspring at chronic consumption of silver nanoparticles. These experiments are conducted in the laboratory using the water Morris maze and the author's methods of animals selection and training (see our paper here (PDF, 270K)). In spite of our results still indicated the absence of serious brain dysfunctions in animals with chronic consumption of nanoparticles, the study also gave the unexpected secondary fundamental results:
1) It is possible that the relative mass of the animals' brain relative to the body weight is more higher when the more higher animal's cognitive abilities are shown in the Morris test. This can serve as an additional objective criterion for the correct selection of animals in groups according to the level of cognitive abilities based on the performance of the cognitive Morris test (see the article with preliminary results here (PDF, 434K)).
2) The memory of the passage of the water maze in animals is preserved for a long time, probably for the whole life.
3) Silver nanoparticles accumulated in the body of females and/or males may possibly contribute to the birth of identical twins (see the article with preliminary results here (PDF, 454K)).