Preparation, properties and antibacterial applications of medical nano-metals and their oxides: a review / 生物工程学报

Antibiotics are playing an increasingly important role in clinical antibacterial applications. However, their abuse has also brought toxic and side effects, drug-resistant pathogens, decreased immunity and other problems. New antibacterial schemes in clinic are urgently needed. In recent years, nano-metals and their oxides have attracted wide attention due to their broad-spectrum antibacterial activity. Nano-silver, nano-copper, nano-zinc and their oxides are gradually applied in biomedical field. In this study, the classification and basic properties of nano-metallic materials such as conductivity, superplasticity, catalysis, and antibacterial activities were firstly introduced. Secondly, the common preparation techniques, including physical, chemical and biological methods, were summarized. Subsequently, four main antibacterial mechanisms, such as cell membrane, oxidative stress, DNA destruction and cell respiration reduction, were summarized. Finally, the effect of size, shape, concentration and surface chemical characteristics of nano-metals and their oxides on antibacterial effectiveness and the research status of biological safety such as cytotoxicity, genotoxicity and reproductive toxicity were reviewed. At present, although nano-metals and their oxides have been applied in medical antibacterial, cancer treatment and other clinical fields, some issues such as the development of green preparation technology, the understanding of antibacterial mechanism, the improvement of biosafety, and the expansion of application fields, require further exploration.

Synthesis of hydrogel polymer coated ZnO nanoparticles and their decontaminating effect against soman in vitro / 中国药理学与毒理学杂志

OBJECTIVE To evaluate the decontamination capability of hydrogel polymer coated ZnO nanoparticles (ZnO NP-gel) against soman. METHODS ZnO NP was synthetized using chemical precipitation method and modified with 4-pentenoic acid,and then polymerized with comonomers to obtain ZnO NP-gel. The transmission electron microscope (TEM), scanning electron microscope (SEM) and particle size instrument were used to observe the internal structure,micromorphology,particle size and zeta potential of these materials. An infrared spectroscope (IR) was used to analyze their chemical bond structure,while X-ray diffraction (XRD) was used to analyze the diffraction pattern.The content of soman was determined by benzidine chromogenic reaction. ZnO NP(1 g·L-1), ZnO NP-gel (1 g·L-1) and distilled water were mixed with soman(52.2 mg·L-1),stood for 30 min,and then filtered before filtrate was subcutaneously injected into mice (40 μL·g-1) to observe the symptoms of poisoning and death. RESULTS SEM and TEM showed that ZnO NP-gel had a block structure, the zeta potential of which was (-7.89 ± 0.04) mV. The results of IR indlicated that ZnO NP-gel had stronger absorption peaks at 754 and 618 cm-1, and XRD revealed that these materials had a sharp peak at 2θ=8.06738°. The decontamination efficiency of ZnO NP-gel was higher than that of ZnO NP group at the same concen?tration (n=3, P<0.05), and the time for decontamination of 50% soman was shortened by four times. The mice were injected subcutaneously with the soman solution treated with ZnO NP-gel, which caused no convulsion or death. CONCLUSION ZnO NP-gel can perform the double function of fast adsorption and catalysis of soman,and the decontamination ability of which could be improved through polymer modification.

A new metallic oxide semiconductor field effect transistor detector for use of in vivo dosimetry / 中华放射肿瘤学杂志

To investigate the application of a recently developed metallic oxide semiconductor field effect transistor(MOSFET)detector for use in vivo desimetry.Methods The MOSFET detector was calibrated for X-ray beams of 8 MV and 15 MV,as well as electron beams with energy of 6,8,12 and 18 MeV.The dose linearity of the MOSFET detector was investigated for the doses ranging from 0 up to 50 Gy using 8 MV X-ray beams.Angular effect was evaluated as well in a cylindrical PMMA phantom by changing the beam entrance angle every 15?clockwise.The MOSFET detector was then used for a breast cancer patient in vivo dose measurement, after the treatment plan was verified in a water phantom using a NE-2571 ion chamber,in vivo measurements were performed in the first and last treatment,and once per week during the whole treatment.The measured doses were then compared with planning dose to evaluate the accuracy of each treatment.Results The MOSFET detector represented a good energy response for X-ray beams of 8 MV and 15 MV,and for electron beams with energy of 6 MeV up to 18 MeV.With the 6 V bias,Dose linearity error of the MOSFET detector was within 3.0% up to approximately 50 Gy,which can be significantly reduced to 1% when the detector was calibrated before and after each measdurement.The MOSFET response varied within 1.5% for angles firm 270?to 90?.However,maximum error of 10.0% was recorded comparing MOSFET response between forward and backward direction.In vivo mea surement for a breast cancer patient using 3DCRT showed that,the average dose.deviation between measurement and calculation was 2.8%,and the maximum error was less then 5.0%.Conclusions The new MOSFET detector,with its advantages of being in size,easy use,good energy response and dose linearity,can be used for in vivo dose measurement.