Experts from Institute of high energy, Chinese Aca

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Experts from the Institute of high energy of the Chinese Academy of Sciences talk about the research progress of nano toxicology

experts from the Institute of high energy of the Chinese Academy of Sciences talk about the research progress of nano toxicology

October 31, 2005

when this field is still in its early stage and human beings are limited by nano materials, we must pay attention to the biological toxicity of nano materials. We must face this problem now, not after nanotechnology has been widely used—— American nano chemist Vicki Colvin

nano materials with excellent performance, good-looking and easy-to-use are also likely to bring potential toxic effects to human body. This message, first sent from the scientific community, has recently attracted more and more attention from the government and the public. Then, will products made of nano materials, especially artificial nano materials that directly contact or enter the human body, lead to special biological effects? If there is poison, how big is its effect? With these questions in mind, I interviewed researcher Zhao Yuliang from the biological effects Laboratory of nanomaterials, Institute of high energy physics, Chinese Academy of Sciences

at the end of 2001, Zhao Yuliang proposed to the Institute of high energy to establish a "nano biological effect laboratory", which will take advantage of the large scientific platform of the Institute of high energy and combine the rich experience of the Key Laboratory of nuclear analysis in the long-term research on the biological effects of rare earth and heavy metals, the toxicology of organic halogens and environmental toxicology to carry out the research on the biological effects, including toxicity, of nano materials. After the completion of the laboratory, a series of research results have been published in American and European professional journals, starting from the aspects of individuals, organs, tissues, cells, molecules and so on. In order to help the public and relevant researchers objectively understand the toxicity of nano materials, he is requested to comprehensively introduce the research status of toxicology of nano materials and established experimental methods, and make a comprehensive evaluation of this field in combination with his own research

"when substances are subdivided into nano scale, their properties change greatly, resulting in their physiological behavior in organisms, which may also be very different from conventional substances. Therefore, the safety evaluation of macro substances, including the impact on human health and ecological environment, may not be applicable to nano scale substances." Zhao Yuliang pointed out that based on the current research results of biological effects of nano materials, nano particles 1. First, check whether the host part is installed with vertical particles, which leads to some special physiological phenomena in the organism. It is still impossible to explain them only by using existing knowledge, but scientists also summarized some laws: for example, the same nano material at the same dose shows a trend of "size reduction, toxicity increase"; Another example is that nanoparticles are easy to enter cells, which just becomes the basis for the efficient utilization of nano drugs, and so on

Zhao Yuliang said: "At present, the research on the toxicology of nano materials is still in its infancy. The biological effects produced by the interaction between nano materials and life processes may be positive or negative. Among them, the positive effects are the basis of nano biomedicine; in addition to research and application, the negative effects also need to be applied to nano medical diagnosis and treatment technology through reverse application research - just as we are doing now." He said that so far, scientists have conducted preliminary studies on the biological effects of several nano materials, such as nano titanium dioxide (TiO2), nano silicon dioxide, carbon nanotubes, fullerenes, metal fullerenes, nano iron powder, nano copper powder, nano zinc powder, etc

l0 - carton length and external dimension (CM)

among them, nano TiO2 is widely used in coating, anti-aging, sewage purification, cosmetics, antistatic and other aspects, so the output is high, and there are many studies on its toxicity. Zhao Yuliang's total 2. Surrounding environment. The results of in vivo and in vitro experiments show that nano-sized TiO2 particles have slightly greater damage to the lungs than micron sized TiO2 particles, which is directly related to the small particle size and large specific surface area of nanoparticles. However, nano TiO2 particles will aggregate and form larger particles. Treatment of primary rat embryonic fibroblasts with 20 nm ultrafine particles may cause apoptosis. However, these in vitro experimental results cannot be inferred into the body. At present, the experimental methods of introducing TiO2 particles into animals mainly include bronchial inhalation and bronchial injection. Compared with the injection method, the inhalation method is closer to the real exposure of human samples, which can be divided into metal and non-metal materials, but there are still many difficulties in operation

carbon nanotubes have excellent mechanical, electronic and chemical properties, and have broad application prospects in many fields. After the emergence of cheap mass production methods of single-walled carbon nanotubes, whether they have an impact on human health has become a matter of great concern. Zhao Yuliang said that a NASA Space Center research team injected 0.1 mg of carbon nanotube suspension into the lungs of rats and mice through the bronchus. After 7 and 90 days, histopathological examination showed that all particles entered the alveoli in a certain way, and even stayed in the lungs for up to 90 days. Single walled carbon nanotubes cause mild inflammation in the lungs of mice, and can also cause the formation of pulmonary granulomas at very low concentrations. It is worrying that granulomas caused by carbon nanotubes are not accompanied by the inflammatory symptoms typically associated with granulomas caused by asbestos and inorganic dust. Of course, these studies are still preliminary. In order to solve the problem of in vivo detection of carbon nanotubes, academician Liu Yuanfang of Peking University and others solved the problem of relatively quantitative detection of carbon nanotubes in animals by using 125I (iodine) atom as a marker and combining the advantages of high sensitivity of ray detection technology

iron widely exists in the environment and is the main component of atmospheric particles. Iron plays an important role in the study of health damage caused by air pollution. Relevant scholars studied the health effects of nano iron powder particles (72 nm, 3 days) inhaled by rats at concentrations of 57 μ g/m3 and 90 μ g/m3, and found that 57 μ g/m3 of nano iron powder particles did not cause significant biological effects in rats, while 90 μ g/m3 of iron powder particles caused a slight respiratory reaction of significantly higher total protein in alveolar lavage fluid. Other reports showed that the expression of ferritin in respiratory epithelial cells increased after exposure to iron containing atmospheric particles. It can be seen that with the increase of exposure dose, nano iron powder has shown slight toxic and side effects

"to ensure that the observed phenomena and the conclusions drawn from them all come from the impact of nano scale characteristics of substances on organisms, pure biology, medicine and nanotechnology can not meet the requirements. The research on the biological effects of nano materials is first faced with great challenges in research methodology." Zhao Yuliang said, "strictly speaking, at present, the research on the biological environmental effects, toxicity and safety of nano materials has just started, the research data is very limited, the research results are also very preliminary, and even the experimental methodology has great difficulties. Because of this, it is easy to make people mistakenly believe that all nano materials are very toxic."

he finally stressed that it is still a difficult problem to evaluate the biological effects of nanoparticles on human body at present, although this is very important in the formulation of policies, regulations and protection standards related to nanotechnology. Like nanotechnology itself, the study of biological effects of nano scale materials will also be a long-term and continuous process; To eliminate the current misunderstanding that "every nanometer is poisonous" and obtain accurate, objective and responsible scientific conclusions, people still need to wait patiently for a few years or more

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