Here we describe a unique process that achieves complete defluorination and decomposition of perfluorinated compounds (PFCs) which comprise one of the most recalcitrant and widely distributed classes of toxic pollutant chemicals found in natural environments. Photogenerated hydrated electrons derived from 3-indole-acetic-acid within an organomodified clay induce the reductive defluorination of co-sorbed PFCs. The process proceeds to completion within a few hours under mild reaction conditions. The organomontmorillonite clay promotes the formation of highly reactive hydrated electrons by stabilizing indole radical cations formed upon photolysis, and prevents their deactivation by reaction with protons or oxygen. In the constrained interlayer regions of the clay, hydrated electrons and co-sorbed PFCs are brought in close proximity thereby increasing the probability of reaction. This novel green chemistry provides the basis for in situ and ex situ technologies to treat one of the most troublesome, recalcitrant and ubiquitous classes of environmental contaminants, i.e., PFCs, utilizing innocuous reagents, naturally occurring materials and mild reaction conditions.

A novel lysosome-targeting ratiometric fluorescent probe (CQ-Lyso) based on the chromenoquinoline chromorphore has been developed for the selective and sensitive detection of intracellular pH in living cells. In acidic media, the protonation of the quinoline ring of CQ-Lyso induces an enhanced intramolecular charge transfer (ICT) process, which results in large red-shifts in both the absorption (104 nm) and emission (53 nm) spectra which forms the basis of a new ratiometric fluorescence pH sensor. This probe efficiently stains lysosomes with high Pearson's colocalization coefficients using LysoTrackerDeep Red (0.97) and LysoTrackerBlue DND-22 (0.95) as references. Importantly, we show that CQ-Lyso quantitatively measures and images lysosomal pH values in a ratiometric manner using single-wavelength excitation.

Surface-enhanced Raman scattering (SERS) can provide fingerprint information of analyte molecules with unparalleled sensitivity. However, quantitative analysis using SERS has remained one of the major challenges owing to the difficulty of obtaining reproducible SERS substrates with high-density hotspots. Here, we report the rational design and fabrication of a binary thiol-capped gold nanoparticle (AuNP) monolayer film (MLF) as a substrate for highly sensitive and quantitative SERS analysis. The two thiol ligands chemically bonded to the AuNPs play different roles: dodecanethiol with a long alkyl chain controls the interparticle gaps and electromagnetic coupling among AuNPs and 4-mercaptopyridine works as a Raman internal standard (IS). The binary thiol-capped AuNPs can self-assemble into an ordered MLF with high-density hotspots and uniformly distributed IS. The asprepared MLF has been demonstrated as a reliable SERS substrate for quantitative detection of fungicide malachite green in aqueous solution, with a high enhancement factor (up to 3.3 × 10 7 ) and a low detection limit (100 pM). Moreover, the MLF SERS substrate is flexible and transparent, which has enabled in situ detection of trace fungicide residues in a shrimp tissue.

Optogenetics combined with electrical recording has emerged as a powerful tool for investigating causal relationships between neural circuit activity and function. However, the size of optogenetically manipulated tissue is typically 1-2 orders of magnitude larger than that can be electrically recorded, rendering difficulty for assigning functional roles of recorded neurons. Here we report a viral vector-delivery optrode (VVD-optrode) system for precise integration of optogenetics and electrophysiology in the brain. Our system consists of flexible microelectrode filaments and fiber optics that are simultaneously self-assembled in a nanoliter-scale, viral vector-delivery polymer carrier. The highly localized delivery and neuronal expression of opsin genes at microelectrode-tissue interfaces ensure high spatial congruence between optogenetically manipulated and electrically recorded neuronal populations. We demonstrate that this multifunctional system is capable of optogenetic manipulation and electrical recording of spatially defined neuronal populations for three months, allowing precise and long-term studies of neural circuit functions.

3D mesoporous BiOBr microspheres were fabricated via a facile, rapid and environmentally friendly one-step solvothermal process without using templates. The physiochemical properties of BiOBr were characterized by XRD, FESEM, TEM and nitrogen adsorption techniques. The photodegradation behaviors of bisphenol A (BPA) catalyzed by BiOBr were investigated under simulated solar light irradiation. The photocatalytic activities of the BiOBr were superior to that of commercial Degussa P25 TiO 2 . Particular attention was paid to the identification of intermediates and acute toxicity of photocatalytic degradation samples of BPA by GC-MS and bioluminescence bacteria, respectively. Deducing from the results, BiOBr can be a good kind of catalyst irradiated by visible light even under sunlight.

the uncertainty of the amount of detected molecules. The spectral instability is mainly due to the orientation fluctuation of molecules and/or the possible chemical reactions between the molecules and the metal substrate. [12][13][14] In principle, this can be avoided by isolating the molecules from the metal surface, for example, by coating a dielectric nanoshell on the metal nanostructures. [6,14,15] The inhomogeneous electromagnetic enhancement can be largely calibrated by implementing an internal standard species that experiences the same enhancement as the analyte molecule, so that the ratio between the Raman intensities of the analyte and the internal standard can be used for quantification. [6,16,17] The uncertainty of the amount of detected molecules is the most notorious because there have been few solutions so far, and the rough estimation of the number of molecules based on the homogenous-adsorption assumption and the detection area/volume has been generally adopted, although the probability of molecules adsorption is different on different facets of the metal nanostructures.Herein, we report a graphene-based SERS (G-SERS) substrate for analyte quantification that solves the above problems to a great extent. Graphene has shown its unique characteristics in SERS applications. [18][19][20][21] For example, graphene quenches the fluorescence of fluorophores and provides stable and clean Raman signals due to the separation of molecules from a metal. [18,19] Graphene has also been used to cover the surface of plasmonic nanostructures and the composite substrate can provide remarkable Raman enhancement. [22,23] More importantly, the single-crystalline nature of graphene guarantees that the probe molecules are homogeneously adsorbed on the surface, rendering the possibility of reliable determination of the number of molecules. Meanwhile, graphene is naturally an internal standard for the normalization of the Raman signals of analytes, so that the different enhancement experienced by molecules at different locations can be calibrated. In our substrate, a roughened metal film under graphene ensures that the overall Raman enhancement is still dominated by the sizable electromagnetic enhancement. We demonstrated in situ quantitative detection of crystal violet (CV) and rhodamine B (RhB) molecules in aqueous solutions with concentrations from 10 −8 to 10 −5 m and the real-time monitoring of a release process of RhB molecules through a permeable membrane. Our graphene-based SERS substrate promises SERS quantification Quantitative surface-enhanced Raman spectroscopy (SERS) with ultrahigh sensitivity will significantly promote its practical application in many fields, such as environment monitoring, food safety, and drug detection. However, the challenges that remain unresolved, particularly in the low concentration levels, arise from the instability of the SERS spectra and the uncertainty of the number of detected molecules. Herein, a graphene-based, flexible, and transparent substrate for SERS quantification is rep...

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Implantable microelectrodes that can be remotely actuated via external fields are promising tools to interface with biological systems at a high degree of precision. Here, we report the development of flexible magnetic microelectrodes (FMμEs) that can be remotely actuated by magnetic fields. The FMμEs consist of flexible microelectrodes integrated with dielectrically encapsulated FeNi (iron−nickel) alloy microactuators. Both magnetic torqueand force-driven actuation of the FMμEs have been demonstrated. Nanoplatinumcoated FMμEs have been applied for in vivo recordings of neural activities from peripheral nerves and cerebral cortex of mice. Moreover, owing to their ultrasmall sizes and mechanical compliance with neural tissues, chronically implanted FMμEs elicited greatly reduced neuronal cell loss in mouse brain compared to conventional stiff probes. The FMμEs open up a variety of new opportunities for electrically interfacing with biological systems in a controlled and minimally invasive manner.