The development of an effective method for detecting heavy-metal ions remains a serious task because of their high toxicity to public health and environments. Herein, a new electrochemical method based on a graphene aerogel (GA) and metal–organic framework (MOF) composites was developed for simultaneous detection of multiple heavy-metal ions in aqueous solutions. The GA-MOF composites were synthesized via the in situ growth of the MOF UiO-66-NH2 crystal on the GA matrix. GA not only serves as the backbone for UiO-66-NH2 but also enhances the conductivity of the composites by accelerating the electron transfer in the matrix. UiO-66-NH2 worked as a binding site for heavy-metal ions because of the interaction between hydrophilic groups and metal cations. The detection performance of the GA-UiO-66-NH2 composite-modified electrodes was determined. The developed electrochemical method can be successfully applied for individual and simultaneous detection of heavy-metal ions, namely, Cd2+, Pb2+, Cu2+,and Hg2+, in...

Graphene Aerogel-Metal-Organic Framework-Based Electrochemical Method for Simultaneous Detection of Multiple Heavy-Metal Ions.

Recent developments in bio-monitoring via advanced polymer nanocomposite-based wearable strain sensors.

Recent advances in 3D g-C3N4 composite photocatalysts for photocatalytic water splitting, degradation of pollutants and CO2 reduction

Photocatalytic degradation of methylene blue in aqueous solution by using ZnO-SnO2 nanocomposites

Highly-efficient technologies are urgently needed to remove environmental organic pollutants. Photocatalytic degradation and Fenton (-like) process are often used to remove organic pollutants. But simplex photocatalysis is a rather slow process, while Fenton-like process is often limited by low pH levels. Introducing photocatalysis into Fenton-like process to form photocatalytic Fenton-like system is a promising method to overcome these drawbacks. This work investigated a simulated-solar light (SSL) driven photocatalytic Fenton-like process with using a novel biomimetic photocatalyst hemin-Bi2WO6 induced by H2O2 (SSL/H-Bi2WO6/H2O2 process) to degrade organic pollutants. H-Bi2WO6 possesses lower fluorescence intensity and faster electron transport than pristine Bi2WO6. Additionally, combined experimental and theoretical investigations indicated that SSL/H-Bi2WO6/H2O2 process revealed a high catalytic activity with enhanced pH tolerance. Furthermore, trapping experiments and electron spin resonance tests were used to explore the reaction mechanism of photodegradation. Presumably, the degradation of organic pollutants over SSL/H-Bi2WO6/H2O2 process was ascribed to ·OH, h+, and ·O2− radical species, and Fe(IV)   O active species generated from the interaction of H2O2 with the variable valence state of iron on H-Bi2WO6. Overall, this work puts forward a new possibility for aqueous organic pollutants removal via SSL/H-Bi2WO6/H2O2 process, which may promote the application of photocatalytic Fenton-like process and biomimetic catalysis.

Advanced photocatalytic Fenton-like process over biomimetic hemin-Bi2WO6 with enhanced pH

A three-dimensional hemin-functionalized graphene hydrogel (Hem/GH) was prepared by a facile self-assembly approach. The as-prepared Hem/GH showed good mechanical strength with a storage modulus of 609–642 kPa and a high adsorption capacity to organic dye contaminants (341 mg g–1 for rhodamine B). Moreover, Hem/GH could be used as a photosensitizer for the photocatalytic degradation of organic dyes and displayed superior photodegradation activity of methylene blue (MB). This result was better than that of counterparts such as graphene hydrogel (GH) and commercial catalyst P25. The excellent cycling performance of the Hem/GH was well maintained even after multiple cycles on adsorption process and photocatalytic reaction. Interestingly, after the photodegradation of MB, a light-induced pH change of the solution from alkaline pH 8.99 to acidic pH 3.82 was observed, and 10 wt % total organic carbon remained. The liquid chromatography/time-of-flight mass spectrometry (LC/TOF-MS) analysis confirmed the generati...

Construction of Three-Dimensional Hemin-Functionalized Graphene Hydrogel with High Mechanical Stability and Adsorption Capacity for Enhancing Photodegradation of Methylene Blue.

Multifunctional nanoprobe for cancer cell targeting and simultaneous fluorescence/magnetic resonance imaging.

Photodynamic therapy (PDT) is an effective and promising method for cancer treatment, which is proposed for more than one century. However, the specific delivery of photosensitizer to target carcinoma cells to reduce the side effect is still a great challenge. This work provides a strategy to deliver photosensitizers to cancer cells by utilizing pH-sensitive polyethylene glycol metal-phenolic network (PEG-MPN) capsules to encapsulate haematoporphyrin monomethyl ether (HMME). With the assistance of folic acid (FA), HMME-doped PEG-MPN capsules (MPN@HMMEs) accumulate in carcinoma cells selectively followed by releasing HMME in the lysosomes because of the physiologically relevant acidic pH environment. From the fluorescent ratiometric sensing and reactive oxygen species (ROS) regionality distribution of MPN@HMMEs, we demonstrated the encapsulated photosensitizers are diffused from lysosomes to cytoplasm. Under irradiation at 638 nm laser, ROS generated from the photosensitizers induced cancer cells undergoing apoptosis while normal cells survive. Therefore, MPN@HMME could be applied as a new strategy for targeted PDT against cancer and PEG-MPN capsules are expected to be general carries for drug delivering.

pH-sensitive metal-phenolic network capsules for targeted photodynamic therapy against cancer cells

Two new compounds, ardisiapunine B (1) and ardisiapunine C (2), were isolated from Ardisia lindleyana D. Dietr. Their structures were examined using HR–ESI–MS, IR, (1D, 2D) NMR spectroscopic analyses, single–crystal X–ray diffraction, and ECD calculation. It was found that the two new compounds belong to unusual oleanane-type triterpenes, with compound 1 bearing an acetal unit and a C–13–C–18 double bond, and compound 2 bearing a C–28 aldehyde group and a C–18–C–19 double bond. The anti-inflammatory properties of compounds 1 and 2 were tested on NO production and cellular morphology using RAW264.7 cells, and their anti-tumor properties were tested on cytotoxic activities, cellular morphology, cell apoptosis, and cell cycle. The results showed that compound 1 exhibited a potent cytotoxicity against HepG2 cell lines with an IC50 of 12.40 μM. Furthermore, it is possible that compound 1 inhibits cell proliferation by blocking the cell G2/M phase and promoting cell apoptosis. Compound 2 exhibited a potential anti-inflammatory activity by decreasing the production of NO in LPS–stimulated RAW264.7 cells. Comparative analysis of the structures of compounds 1 and 2 revealed that the acetal structure and double bond positions were the main differences between them, and these are presumed to be the main reasons for the extreme differences in their cytotoxicity and anti-inflammatory activities. From these new findings, two promising lead compounds were identified for the future development of potential anti–inflammatory or anti–tumor agents.

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Zhenzhen Wei

Papers

Construction of Three-Dimensional Hemin-Functionalized Graphene Hydrogel with High Mechanical Stability and Adsorption Capacity for Enhancing Photodegradation of Methylene Blue.

Multifunctional nanoprobe for cancer cell targeting and simultaneous fluorescence/magnetic resonance imaging.

pH-sensitive metal-phenolic network capsules for targeted photodynamic therapy against cancer cells

Absolute Configuration and Biological Evaluation of Novel Triterpenes as Possible Anti-Inflammatory or Anti-Tumor Agents