Nanoparticles have important scientific research value, which has a bridge between large blocks and atoms and molecules. The physical properties of large blocks are usually not related to the size, but it is often not the case in nano size. Some special physical properties are currently observed, such as the quantum bondage of semiconductor nanoparticles, some of the surface plasma resonance of some metal nanoparticles, and the ultra-smooth magnetic properties of the magnetic material. The solid and soft nanoparticles are also manufactured. Liposomes are typical nanoparticles having solid properties.
Nanoparticles are micro particles that are artificially manufactured, no more than 100 nm. Its form may be emilings, polymers, ceramic particles, metal particles, and carbon particles. The nanoparticles are increasingly applied to medical, sunscreen cosmetics.
Nanoparticles can penetrate into membrane cells and spread along nerve cell synapses, vascular and lymphocysto. At the same time, nanoparticles are selectively accumulated in different cells and a certain cell structure. The strong permeability of nanoparticles is not only for the use of drugs, but also pose potential threats to human health. But now, the research on nanoparticles on human health hazards is still very small.
Scientific point of view
Durnev believes that at present, the most important problem is to study nano-toxicology, that is, the nanoparticles rely on its shape, size, raw material, surface size. , With charge and amount of biological and toxicology exhibited by the amount, the time, etc.
Durnev pointed out that the drug nanoparticles and drug itself have principles to distinguish between principles, and the method of general drug safety assessment is not suitable for nanoparticles. For example, studying nano-characteristic experiments is preferably carried out on a living body without performing in cell tissue. Because nano-drug particles are dedicated to patient, that is, tests should be carried out on a living body that simulates certain diseases. In addition, you can't forget that in genetic people are varied, many people are very sensitive to nano drugs.
Durnev believes that the study to assess the method of nanopartic toxicity and the necessary tests for a long time, which will inevitably delay the promotion of nano drugs in medicine, but the development of nanotechnology technology is far away. Far exceeded the research on its product toxicity, this is a bad trend. He also pointed out that in addition to some unpredictable medical consequences, using unspected nanomaterials will result in huge property losses.
On August 19, 2009, Chinese researchers report on Wednesday that seven Chinese young women working in the nano-coating plant for several months were there without appropriate protection measures. Permanent lung damage, two of them died.
The study recorded the health damage caused by human beings for the first time. In the past, there were studies to show that nanoparticles can cause damage to the lungs of mice. It was found that particles having a diameter of 30 nm were found in the workplace of these female workers, bronchioliolioli, pleural effusion and lung biopsy (Figures 1-4). It was observed under electrical microscopy, which were distributed in cytoplasm and nucleus of lung epithelial and empty cells. Pulmonary epithelial cells curled up, showing apoptotic form (Figure 5). Through examination, all cases exclude the possibility of infection, malignant tumor, immune-related diseases, etc. Considering the similar pathological changes in patients, the nanoparticles are found after the animal's broncho, and the pulmonary tissue is found in the patient's bronchi, and therefore, it is speculated that the disease performance and pathological changes of these patients may be with the nanoparticles in the plant. Related. In Beijing Chaoyang Hospital, Song Junguo, published articles on the European Respiratory Japan: "These cases give people a warning, and there is no protection measures, long-term exposure can be exposed in the nano-environment. It will cause serious damage to the human lungs. "But an expert from the US government said that this study can only prove that there is industrial hazard, but it is impossible to prove that nanoparticles have a greater threat to other chemicals.
Science research often requires different deposition methods to uniformly disperse the nanoparticles in the surface of the substrate. Based on the coating method used, the coating can be a single layer or a multi-layer, organized or non-tissue. Nanoparticles are generally difficult to deposit on the surface of the substrate due to its physical properties, typically need to deposit nanoparticles in the surface of the substrate using a particular method.
LB membrane method
In the LB film method, the nanoparticles are injected into the gas-liquid interface groove. The floating particles are compressed by slippery, and the computer is accurately controlled to control the deposition density of the particles. After the particles are compressed to the desired deposit density, they are transferred to the solid substrate using a vertical or horizontal plating method to produce a single layer film; repeated pulling the multilayer film.
Rehabilitation and spin coating
dip coating and spin coating method are a simple method of depositing nanoparticles. When the bulk density is not necessary, the nanoparticle adsorption layer can be quickly and easily prepared using a dip coating and a spin coating method.
Other possible deposition methods include solvent evaporation, blade, chemical vapor deposition, and transfer methods, and the like.