量子点-Cu2+对L02细胞的联合毒性及NAC的防护作用

以人胚肝细胞(L02)为研究对象,通过研究量子点及Cu2+ (低毒浓度)联合对细胞存活率的影响以及细胞形态的变化确认细胞的毒性,结合抗氧化剂NAC的防护效果探讨复合毒性的氧化损伤机理.结果表明,无论单独Cu2+还是量子点-Cu2+处理组,L02细胞的增殖能力均受到抑制,量子点-Cu2+处理组表现出更加显著的抑制效果,相对与单独Cu2+处理组细胞存活率最大下降300%.经过NAC预处理的细胞在形态和存活率上都显著恢复.说明了安全浓度范围的量子点的与Cu2+共存提高了细胞毒性风险,NAC能够防护量子点与Cu2+单独或联合引起的氧化损伤.     

Effect of molecular properties on the photocatalytic degradation rates of dichlorophenols and dichloroanilines in aqueous TiO2 suspensions

The kinetics of the photocatalytic degradation of 10 different dichlorophenols and dichloroanilines have been investigated experimentally and theoretically. With the intention of finding certain molecular indices in order to determine the degradation rates of aromatic pollutants, geometry optimizations of the compounds have been performed with the semiempirical PM3 method. The molecular orbital calculations have been carried out by an SCF method using the RHF formalism. The correlations between the apparent first-order rate constants and the calculated molecular properties of the compounds have been examined. Four different structure–activity relationships have been developed expressing the logarithms of the rate constants in terms of the Hammett constants, electron densities of the substituents, the coefficients and the energies of the highest occupied molecular orbitals HOMO, and 1-octanol/water partition coefficients log?K _OW.     

基于氮掺杂碳量子点的制备及其对Hg2+的响应

以乙二胺和抗坏血酸为原料,通过一步水热法制备了水溶性的氮掺杂碳量子点(N-CQDs).研究了N-CQDs的形貌特征、光学性能和应用分析.表征结果说明,N-CQDs形态为均匀分散的球形,有明显的晶格条纹,抗光漂白性能良好,表面富有含氧官能团,具有良好的水溶性.此外发现N-CQDs还具有优良的荧光性能和荧光稳定性,量子产率可以高达12.29%.分析得出,Hg²⁺对N-CQDs在1.0—120μmol·L^-1范围内有一定的猝灭效应,可作为Hg²⁺的荧光探针,检出限达230 nmol·L^-1.     

共振能量转移同步荧光猝灭法测定水体中孔雀石绿

采用L-半胱氨酸、巯基乙酸为稳定剂水相合成Cd Te量子点,且以Cd Te量子点为能量供体、孔雀石绿为能量受体建立荧光共振能量转移体系,从而实现孔雀石绿含量的同步荧光猝灭法测定。结果表明,当固定波长差为220 nm时,Cd Te量子点的同步荧光最大发射波长位于323 nm。在最优实验条件下,体系的同步荧光淬灭强度与孔雀石绿的浓度在0.5~10.0μmol/L范围内呈良好的线性关系,相关系数为0.9995,方法的检出限为10 nmol/L。该方法用于实际水样中孔雀石绿含量的测定,加标回收率为94%~105%。     

Effects of wavelength and water quality on photodegradation of N-Nitrosodimethylamine (NDMA)

N-Nitrosodimethylamine (NDMA) is a potent carcinogen that yields a cancer risk of 10⁻⁶ at concentrations as low as 0.7 ng L⁻¹. Tentative guideline values are set at 3 ng L⁻¹ in California, USA; 9 ng L⁻¹ in Ontario, Canada; 40 ng L⁻¹ nationwide in Canada; and 100 ng L⁻¹ by the World Health Organization. NDMA is a great concern in treating reclaimed water as well as drinking water. UV degradation can be considered effective degradation method. A 1-log reduction of NDMA is achieved by 1000 mJ cm⁻² of a 254-nm low pressure (LP) mercury UV lamp. However, a higher degradation efficiency than that provided by LP lamps is desired in practical treatment. In this study, the effects of wavelength and water quality were investigated to achieve higher degradation efficiency. The effects of wavelength were examined by comparing three UV lamps: a 222-nm Kr Cl Excimer UV lamp, a 254-nm LP mercury UV lamp, and a 230- to 270-nm filtered medium pressure (FMP) mercury UV lamp. The 222-nm lamp and FMP lamp achieved 4 times and 2.8 times higher degradation efficiency, respectively, than the conventional 254-nm LP lamp. Effects on water quality were also simulated by using absorption spectrum data of nitrate solutions and process water from a drinking-water treatment plant. In the simulation, the 222-nm lamp was affected by UV-absorbing compounds in the water, whereas the FMP lamp showed more stable degradation efficiency. Appropriate use of these three types of lamps could enhance the efficiency of degradation of NDMA.     

A rapid and high-throughput quantum dots bioassay for monitoring of perfluorooctane sulfonate in environmental water samples

Currently HPLC/MS is the state of the art tool for environmental/drinking water perfluorooctane sulfonate (PFOS) monitoring. PFOS can bind to peroxisomal proliferator-activated receptor-alpha (PPARα), which forms heterodimers with retinoid X receptors (RXRs) and binds to PPAR response elements. In this bioassay free PFOS in water samples competes with immobilized PFOS in ELISA plates for a given amount of PPARα-RXRα. It can be determined indirectly by immobilizing PPARα-RXRα-PFOS complex to another plate coated with PPARα antibody and subsequent measuring the level of PPARα-RXRα by using biotin-modified PPARα-RXRα probes-quantum dots-streptavidin detection system. The rapid and high-throughput bioassay demonstrated a detection limit of 2.5 ng L⁻¹ with linear range between 2.5 ng L⁻¹ and 75 ng L⁻¹. Detection results of environmental water samples were highly consistent between the bioassay and HPLC/MS.     

Enhanced Photocatalysis of Pentachlorophenol by Metal-Modified Titanium (IV) Oxide

The effects of four metals (Ag, Au, Pt, and Cu) doped on TiO₂ on the photocatalysis of pentachlorophenol (PCP) were investigated. The results of this study indicated that all four metals-doped TiO₂ catalysts were able to enhance the efficiency of PCP photocatalysis with an optimum metallic content of 0.1 wt%. For the metal-doped TiO₂ samples (Au, Pt, and Cu), the patterns of light absorption were significantly extended toward visible light spectra in the wavelengths between 400 and 800 nm. The photocatalysis of PCP was pH dependent with the maximum degradation rate achieved in the solution at pH 3. The formation of chloride ion corresponded with the concentration of PCP degraded which confirmed that dechlorination was the major pathway of PCP photocatalysis. The overall toxicities of PCP samples were reduced with the extension of light exposure using the microtox test. The results of PCP photocatalysis are also discussed based on the characteristics of metal/TiO₂ including X-ray differential (XRD) patterns, Brunquer Emmett Teller (BET) specific area analysis, and Ultra Violet (UV)-Vis absorption spectra.     

Design and prediction for highly efficient SO2 capture from flue gas by imidazolium ionic liquids

An efficient method for prediction in the capture of SO2 from flue gas by imidazolium ionic liquids was reported, where the concentration of SO2 is 2000 ppm. On the basis of quantitative calculations through a combination of Langmuir simulation, theoretical calculation and quantum chemical method, SO2 absorption and desorption performance from flue gas by twelve kinds of imidazolium ionic liquids with different anions were designed and predicted. Then, among them, five kinds of imidazolium ionic liquids were chosen and prepared to investigate their behavior of SO2 absorption capacity, desorption residue, and available absorption capacity. The results indicated that the experimental values were in good agreement with the predicted values. Thus, an ideal ionic liquid [Emim][Tetz] was obtained through the predictive method for the capture of SO2 of 2000 ppm, which showed high available absorption capacity of 0.24 g SO2 per g ionic liquid and excellent reversibility.     

CdSe/ZnS量子点对斑马鱼胚胎发育的毒性效应

本研究以模式生物斑马鱼(Danio rerio)为对象,观察在不同浓度Cd Se/Zn S量子点(Cd Se/Zn S QDs)暴露下,斑马鱼胚胎形态发育、氧化应激以及金属硫蛋白MT基因和应激蛋白Hsp70基因表达变化情况.结果表明,Cd Se/Zn S QDs对斑马鱼胚胎72 hpf(hours post fertilization)的半致畸效应浓度(EC50)为316.994 nmol·L-1.QDs暴露影响了斑马鱼胚胎的死亡率、畸形率、孵化率、自主运动频率和体长,以及引起胚胎卵凝集,心包囊肿,脊椎弯曲等多种毒性效应;同时导致斑马鱼体内超氧化物歧化酶(SOD)活性变化以及丙二醛(MDA)含量增加.QDs还诱导斑马鱼MT基因和Hsp70基因表达上调,斑马鱼机体产生一系列自我保护反应来减轻QDs所造成的伤害.这表明:Cd Se/Zn S QDs对斑马鱼胚胎产生了毒性效应,其毒性可能与其核心Cd2+的释放、粒径大小以及氧化应激有关.     

量子点在环境污染物检测中的应用研究进展

量子点是半径小于或接近于激子玻尔半径的一类半导体纳米晶,具有激发光谱宽、发射光谱窄且对称、最大发射波长位置可调、不易光降解的特点。作为一种新型的荧光标记物,量子点因其独特而优良的光学性质已在生物和医学研究领域中得到了广泛的应用。文章对量子点在环境有机污染物、重金属离子、微生物分析检测中的应用进行了综述,介绍了量子点荧光淬灭法、荧光增敏法、量子点标记免疫分析法、量子点表面印迹法、荧光共振能量转换法等不同的作用机制在环境污染物检测中的应用,并对方法的检出限及所应用的环境样品进行了阐述,在重金属的检测中,对量子点和稳定剂不同时方法的检出限进行了对比研究。同时指出了需要进一步关注的问题,展望了其发展方向。