WS2 nanosheets-based electrochemical biosensor for highly sensitive detection of tumor marker miRNA-4484.

In this paper, a few-layer WS2 nanosheets-based electrochemical biosensor was fabricated for the highly sensitive detection of breast cancer tumor marker miRNA-4484. Firstly, few-layer WS2 nanosheets were prepared by shear stripping and characterized by SEM, TEM, AFM and UV spectrophotometer. After modification of few-layer WS2 nanosheets on the electrode surface, the miRNA probe was fixed on the few-layer WS2 nanosheets by polycytosine (PolyC). Then short-chain miRNA containing PolyC was used as the blocking agent to close the excess active sites on the surface of WS2 nanosheets to complete the fabrication of the sensor biosensing interface. Finally, the current changes caused by the specific binding of miRNA-4484 to the probe were analyzed by differential pulse voltammetry (DPV). The results showed that the sensor had a good linear relationship for the detection of miRNA-4484 in the concentration range of 1 aM-100 fM, and the detection limit was as low as 1.61 aM. In addition, the electrochemical sensor had excellent selectivity, stability and reproducibility. The artificial sample tests indicated that the developed biosensors have the potential for clinical application in the future.

Ambient air pollution of particles and gas pollutants, and the predicted health risks from long-term exposure to PM2.5 in Zhejiang province, China.

In recent years, ambient air has been severely contaminated by particulate matters (PMs) and some gas pollutants (nitrogen dioxide (NO2) and sulfur dioxide (SO2)) in China, and many studies have demonstrated that exposure to these pollutants can induce great adverse impacts on human health. The concentrations of the pollutants were much higher in winter than those in summer, and the average concentrations in this studied area were lower than those in northern China. In the comparison between high-resolution emission inventory and spatial distribution of PM2.5, significant positive linear correlation was found. Though the pollutants had similar trends, NO2 and SO2 delayed with 1 h to PM2.5. Besides, PM2.5 had a lag time of 1 h to temperature and relative humidity. Significant linear correlation was found among pollutants and meteorological conditions, suggesting the impact of meteorological conditions on ambient air pollution other than emission. For the 24-h trend, lowest concentrations of PM2.5, NO2, and SO2 were found around 15:00-18:00. In 2015, the population attributable fractions (PAFs) for ischemic heart disease (IHD), cerebrovascular disease (stroke), chronic obstructive pulmonary disease (COPD), lung cancer (LC), and acute lower respiratory infection (ALRI) due to the exposure to PM2.5 in Zhejiang province were 25.82, 38.94, 17.73, 22.32, and 31.14%, respectively. The population-weighted mortality due to PM2.5 exposure in Zhejiang province was lower than the average level of the whole country-China.

Characteristics of ambient ozone (O3) pollution and health risks in Zhejiang Province.

Troposphere ozone, which is from secondary formation processes, has been increasing dramatically during the last decades in China, inducing high health risks. In this study, temporal and spatial distribution of O3 was studied among 13 sites of three cities during 2014-2016. The objectives were to clarify the characteristics of the ambient pollution of O3 under the influence from other pollutants and meteorological parameters and the health outcomes from exposure to O3. The concentrations of O3 during summer were much higher than those during winter, and the concentrations in downtown areas were higher than in rural or mountain areas. PM2.5, NO2, SO2, and wind speed (WS) were negatively correlated with O3, and CO, temperature (T), and relative humidity (RH) were positively correlated with O3. In multivariable analysis, two separate factors-solar radiation and atmospheric diffusion status, affected the O3 levels. The concentrations of O3 reached the highest level at 15:00 and the lowest value at about 6:00-8:00, with the similar trend to T and WS, and opposite to RH. According to the dose-response model, relative risks (RRs) and population attributable fractions (PAFs) with confidence intervals (CIs) for chronic obstructive pulmonary disease (COPD) from exposure to O3 were 1.0612 (CI 1.0607-1.0616) and 5.32% (CI 5.29-5.36%), respectively, attributable to 2000 deaths in Zhejiang Province in 2014.