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Developing real-time, dynamic, and in situ analytical methods with high spatial and temporal resolutions is crucial for exploring biochemical processes in the brain. Although in vivo electrochemical methods based on carbon fiber (CF) microelectrodes are effective in monitoring neurochemical dynamics during physiological and pathological processes, complex post modification hinders large-scale productions and widespread neuroscience applications. Herein, we develop a general strategy for the in situ engineering of carbon-based materials to mass-produce functional CFs by introducing polydopamine to anchor zeolitic imidazolate frameworks as precursors, followed by one-step pyrolysis. This strategy demonstrates exceptional universality and design flexibility, overcoming complex post-modification procedures and avoiding the delamination of the modification layer. This simplifies the fabrication and integration of functional CF-based microelectrodes. Moreover, we design highly stable and selective H + , O 2 , and ascorbate microsensors and monitor the influence of CO 2 exposure on the O 2 content of the cerebral tissue during physiological and ischemia-reperfusion pathological processes., (© 2024 Wiley-VCH GmbH.)

Spreading depolarization (SD) is one of the most common neuropathologic phenomena in the nervous system, relating to numerous diseases. However, real-time monitoring the rapid chemical changes during SD to probe the molecular mechanism remains a great challenge. We develop a potentiometric dual-channel microsensor for simultaneous monitoring of H 2 S and pH featuring excellent selectivity and spatiotemporal resolution. Using this microsensor we first observe real time changes of H 2 S and pH in the rat brain induced by SD. This changes of H 2 S are completely suppressed when the rat pre-treats with aminooxyacetic acid (AOAA), a blocker to inhibit the H 2 S-producing enzyme, indicating H 2 S fluctuation might be related to enzyme-dependent pathway during SD and less pH-dependent. This study provides a new perspective for studying the function of H 2 S and the molecular basis of SD-associated diseases., (© 2024 Wiley-VCH GmbH.)

Nanoplastics are recently recognized as neurotoxic factors for the nervous systems. However, whether and how they affect vesicle chemistry (i.e., vesicular catecholamine content and exocytosis) remains unclear. This study offers the first direct evidence for the nanoplastics-induced neurotoxicity by single-vesicle electrochemistry. We observe the cellular uptake of polystyrene (PS) nanoplastics into model neuronal cells and mouse primary neurons, leading to cell viability loss depending on nanoplastics exposure time and concentration. By using single-vesicle electrochemistry, we find the reductions in the vesicular catecholamine content, the frequency of stimulated exocytotic spikes, the neurotransmitter release amount of single exocytotic event, and the membrane-vesicle fusion pore opening-closing speed. Mechanistic investigations suggest that PS nanoplastics can cause disruption of filamentous actin (F-actin) assemblies at cytomembrane zones and change the kinetic patterns of vesicle exocytosis. Our finding shapes the first quantitative picture of neurotoxicity induced by high-concentration nanoplastics exposure at a single-cell level., (© 2023 Wiley-VCH GmbH.)

As emerging stimuli-responsive materials, electrochromic metal-organic frameworks (MOFs) are still not utilized in sensing applications due to difficulties in water stability, facile synthesis and functionalization, and efficient translation of specific recognition events. Here, we firstly find that a Zr-based MOF furnished with postsynthetically created viologen-like electron-deficient moiety was electrochromic active. With a coordination-driven surface engineering strategy where phosphate-containing biomolecules are tethered to Zr nodes of the MOF, fine tuning the interface electron transfer was readily achieved, thus benefitting for constructing smart electrochromic sensors through the combination of the sensitivity of electrochemistry with the visuality of colorimetry. Particularly, MOF-coated conductive films enabled label-free detection of phosphoproteins, and aptamer-functionalized ones responded specifically to the target. In two cases distinct color changes allow for visual quantification. This study represents the first example of MOF-based electrochromic sensors developed by an efficient strategy, indicating the generality to electrochromic counterparts for various sensing applications., (© 2023 Wiley-VCH GmbH.)

Biological ion channels regulate the ion flow across cell membrane via opening or closing of the pores in response to various external stimuli. Replicating the function of high ion gating effects with artificial porous materials has been challenging. Herein, we report that the self-assembled two-dimensional metal-organic framework (MOF) membrane can serve as an excellent nanofluidic platform for smart regulation of ion transport. The MOF membrane with good photothermal performance exhibits extremely high ion gating ratio (up to 10 4 ), which is among the highest values in MOF membrane nanochannels for light-controlled ion gating reported so far. By repeatedly turning on and off the light, the nanofluidic device shows outstanding stability and reversibility that can be applied in the remote light-switching system. This work may spark promising applications of MOF membrane with variety of stimuli responsive properties in ion sieving, biosensing, and energy conversion., (© 2023 Wiley-VCH GmbH.)

Serotonin (5-HT) is a major neurotransmitter broadly involved in many aspects of feeling and behavior. Although its electro-activity makes it a promising candidate for electrochemical sensing, the persistent generation of fouling layers on the electrode by its oxidation products presents a hurdle for reliable sensing. Here, we present a fouling-free 5-HT sensor based on galvanic redox potentiometry. The sensor efficiently minimizes electrode fouling as revealed by in situ Raman spectroscopy, ensuring a less than 3 % signal change in a 2 hour continuous experiment, whereas amperometric sensors losing 90 % within 30 min. Most importantly, the sensor is highly amenable for in vivo studies, permitting real-time 5-HT monitoring, and supporting the mechanism associated with serotonin release in brain. Our system offers an effective way for sensing different neurochemicals having significant fouling issues, thus facilitating the molecular-level understanding of brain function., (© 2023 Wiley-VCH GmbH.)

Proton conductors have attracted great attention in various fields, especially in energy production. Here, we find that graphdiyne oxide (GDYO), derived from graphdiyne (GDY), features the highest proton conductivity of 0.54 S cm -1 (100 % RH, 348 K) among the oxidized carbon allotropes reported so far. The sp- and sp 2 -co-hybridized carbon skeleton of GDY enables GDYO with the giant water uptake, which is 2.4 times larger than that of graphene oxide (GO), resulting in ultrahigh proton conductivity by increasing the proton concentration and proton conduction pathways. This ultrahigh proton conductivity of GDYO is further proved in a methanol fuel cell by using GDYO membrane as proton exchange membrane. The GDYO membrane enables the cell with higher open circuit voltage, larger power density and lower methanol permeability, compared with commercial Nafion 117. Moreover, the GDYO membrane bears high ion exchange capacity, good acidic stability and low swelling ratio., (© 2022 Wiley-VCH GmbH.)

Biological ion channels penetrated through cell membrane form unique transport pathways for selective ionic conductance. Replicating the success of ion selectivity with mixed matrix membranes (MMMs) will enable new separation technologies but remains challenging. Herein, we report a soft substrate-assisted solution casting method to develop MMMs with penetrating subnanochannels for selective metal ion conduction. The MMMs are composed of penetrating Prussian white (PW) microcubes with subnanochannels in dense polyimide (PI) matrices, achieving selective monovalent metal ion conduction. The ion selectivity of K + /Mg 2+ is up to 14.0, and the ion conductance of K + can reach 45.5 μS with the testing diameter of 5 mm, which can be further improved by increasing the testing area. Given the diversity of nanoporous materials and polymer matrices, we expect that the MMMs with penetrating subnanochannels could be developed into a versatile nanofluidic platform for various emerging applications., (© 2022 Wiley-VCH GmbH.)

Neurochemical events involving biosignals of different time and space dimensionalities constitute the complex basis of neurological functions and diseases. In view of this fact, electrochemical measurements enabling real-time quantification of neurochemicals at multiple levels of spatiotemporal resolution can provide informative clues to decode the molecular networks bridging vesicles and brains. This Minireview focuses on how scientific questions regarding the properties of single vesicles, neurotransmitter release kinetics, interstitial neurochemical dynamics, and multisignal interconnections in vivo have driven the design of electrochemical nano/microsensors, sensing interface engineering, and signal/data processing. An outlook for the future frontline in this realm will also be provided., (© 2022 Wiley-VCH GmbH.)

Interfacing aptamers with carbon fiber microelectrodes (CFEs) provides a versatile platform to probe the chemical activity in a living brain at the molecular level. However, new approaches are needed for the efficient and stable modification of electrode surfaces with aptamers. Here, we present an electrochemical conjugation strategy to covalently couple aptamers onto CFEs with high chemoselectivity, efficiency, and stability for sensing in the brain. The strategy employs an initial electrochemical coupling of catechol on an CFE, thereby generating a thin layer of quinone intermediates that couple rapidly with thiol-containing oligonucleotides under a controlled potential. This approach dramatically simplifies and improves the efficiency for modifying carbon surfaces, thereby allowing direct conjugation of high levels of aptamers on CFEs within 5 minutes. Importantly, the covalent linkage between the aptamers and carbon surfaces enables a greatly improved sensitivity and stability for the sensing of dopamine, offering a robust system for continuously probing dopamine dynamics in the living brains of animals., (© 2022 Wiley-VCH GmbH.)

Nitric oxide (NO) constitutes one of the most versatile therapeutics for biomedical applications. The efficient and on-demand NO generation essentially dictates its concentration dependent therapeutic activity. Here, we report an electrochemical system employing a rationally designed single-iron atom based biomimetic catalyst (i.e., Fe SAC), for high-efficient and controlled NO generation. The Fe SAC shows superior catalytic ability in electrochemical reduction of nitrite, with maximal NO generation rate achieving 2.1 μM (min μg) -1 . Theoretical studies suggest the significant decrease of Gibbs-free energy of NO 2 - adsorption on single-iron atom accounts for its high catalytic efficiency. Moreover, ample amount of NO can be controllably generated in a potential dependent manner. For antibacterial application, the generated NO overwhelmingly disrupts both gram-negative and gram-positive strains, highlighting a great promise to expedite NO research in both basic and applied sciences., (© 2022 Wiley-VCH GmbH.)

Challenges remain in establishing a universal method to precisely tune electrochemical properties of conducting polymers for multifunctional neurosensing with high selectivity and sensitivity. Here, we demonstrate a facile and general approach to achieving synergistic charge percolation in conducting polymers (i.e., poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate), PEDOT:PSS) by incorporating conductive catalysts (i.e., carbon nanotubes, CNTs) and post-processing. The approach shows synergistic effects: (i) CNTs and post-processing together promote PEDOT ordered interconnection for highly efficient charge percolation that accelerates electrochemical kinetics; (ii) CNTs catalyze the electrooxidation of vitamin C for selective electrochemical sensing; (iii) CNTs enhance the charge storage/injection capacity of PEDOT:PSS. The prepared CNT-PEDOT:PSS fiber mechanically matches with neural tissues and is proved to be a biocompatible versatile microsensor capable of high-performance neurosensing in vivo., (© 2022 Wiley-VCH GmbH.)

Ferroptosis is a new form of regulated, non-apoptotic cell death driven by iron-dependent phospholipid peroxidation. Its therapeutic potential is however, greatly limited by the low efficiency of regulating cell ferroptosis in vivo. Herein, we report a PROTAC-based protein degrader that depletes endogenous glutathione peroxidase 4 (GPX4) and induces cancer cell ferroptosis. We demonstrate that a rationally designed GPX4 degrader, dGPX4, can deplete tumor cell GPX4 via proteasomal protein degradation, showing a five-fold enhancement of ferroptosis induction efficiency compared to that of GPX4 inhibition using ML162. Moreover, we show that the intracellular delivery of dGPX4 using biodegradable lipid nanoparticles (dGPX4@401-TK-12) induces cell-selective ferroptosis by targeting cancer cell microenvironment. The in vivo administration of dGPX4@401-TK-12 effectively suppresses tumor growth without appreciable side effects. We anticipate the protein degradation strategy described herein could be easily expanded to other essential regulatory proteins of ferroptosis for developing targeted cancer therapeutics., (© 2022 Wiley-VCH GmbH.)

Developing techniques for the highly sensitive assay of neurotransmitters is essential for understanding physiological and pathological processes. Here, we demonstrate a fast-scanning potential (FSP)-gated organic electrochemical transistor (OECT): for the highly sensitive sensing of dopamine (DA) in a living rat brain. The configuration combines the selectivity of fast-scan cyclic voltammetry (FSCV) with the high sensitivity of an OECT. The combined use of FSP as a gating mode and transconductance (g m ) as a sensing parameter further improve the sensing performance in terms of sensitivity, limit of detection, reproducibility, and stability. The FSP-OECT exhibits a sensitivity of 0.899 S M -1 and a low limit of detection down to 5 nM and was validated for in vivo monitoring of the basal level and electrically stimulated release of DA., (© 2022 Wiley-VCH GmbH.)

Graphdiyne (GDY), a well-known 2D carbon allotrope, demonstrates increasing fantastic performance in various fields owing to its outstanding electronic properties. Owing to its unique properties, electrochemiluminescence (ECL) technology is one powerful tool for understanding fundamental questions and for ultrasensitive sensing and imaging. Here, we firstly find that GDY without any functionalization or treatment shows a strong ECL emission with potassium persulfate (K 2 S 2 O 8 ) as coreactant, which is totally different with other carbon allotropes. Mechanistic study indicates that the ECL emission of GDY is generated by the surface state transition. Interestingly, ECL is generated at 705 nm in the near infrared region with an ECL efficiency of 424 % compared to that of Ru(bpy) 3 Cl 2 /K 2 S 2 O 8 . The study demonstrates a new character of GDY in ECL investigation and sets the stage for the development of GDY for emerging applications, including imaging and light-emitting devices., (© 2022 Wiley-VCH GmbH.)

Biological nanochannels perfectly operate in organisms and exquisitely control mass transmembrane transport for complex life process. Inspired by biological nanochannels, plenty of intelligent artificial solid-state nanopores and nanochannels are constructed based on various materials and methods with the development of nanotechnology. Specially, the light-controlled nanopores/nanochannels have attracted much attention due to the unique advantages in terms of that ion and molecular transport can be regulated remotely, spatially and temporally. According to the structure and function of biological ion channels, light-controlled solid-state nanopores/nanochannels can be divided into light-regulated ion channels with ion gating and ion rectification functions, and light-driven ion pumps with active ion transport property. In this review, we present a systematic overview of light-controlled ion channels and ion pumps according to the photo-responsive components in the system. Then, the related applications of solid-state nanopores/nanochannels for molecular sensing, water purification and energy conversion are discussed. Finally, a brief conclusion and short outlook are offered for future development of the nanopore/nanochannel field., (© 2022 Wiley-VCH GmbH.)

In vivo microelectrodes are essential for neuroscience studies. However, development of microelectrodes with both flexibility and multifunctionality for recording chemical and electrical signals in the same extracellular microspace and modulating neural activity remains challenging. Here, we find that pure PEDOT:PSS fibers (i.e., support-free) exhibit high conductivity, fast heterogeneous electron transfer, and suitable charge storage and injection capabilities, and can thus directly act as microelectrodes not only for chemical and electrophysiological recording in the same extracellular microspace, but also for electromodulation of neural microcircuit activity. Moreover, the microelectrodes mechanically match with neural tissues, exhibiting less foreign body responses. Given the multifunctionality, flexibility, and biocompatibility, the support-free PEDOT:PSS-based microelectrodes offer a new avenue to microelectrode technology for neuroscience research, diagnostics and therapeutics., (© 2022 Wiley-VCH GmbH.)

Quantitative measurements of sex difference in vesicle chemistry (i.e., chemical storage and release) at the single-vesicle level are essential to understand sex differences in cognitive behaviors; however, such measurements are very challenging to conventional analytical methods. By using single-vesicle electrochemistry, we find the duration of single exocytotic events of chromaffin cells prepared from male rats is statistically longer than that from female rats, leading to more neurotransmitter released in the male group. Further analysis reveals that a higher percentage of vesicles in the female group release part of the neurotransmitter, i.e., partial release, during exocytosis than that in male group. This sex dimorphism in neurotransmitter release in exocytosis might relate to the sex difference in the expression of voltage-dependent calcium channels and membrane lipid composition. Our finding offers the first experimental evidence that sex dimorphism even exists in vesicle chemistry, providing a brand new viewpoint for understanding the sex dimorphism in exocytosis., (© 2022 Wiley-VCH GmbH.)

The delivery of protein into mammalian cells enables the dissection and manipulation of biological processes; however, this potency is challenged by the lack of an efficient protein delivery tool and a means to monitor its intracellular trafficking. Herein, we report that the hierarchical self-assembly of tetraphenylethylene (TPE)-featured metal-organic cages (MOCs) and β-cyclodextrin-conjugated polyethylenimine can generate fluorescent supramolecular nanoparticles (FSNPs) to deliver protein into neural cells, a cell line that is hard to transfect using conventional strategy. Further, the aggregation-induced emission (AIE) of TPE enabled the fluorescent monitoring of cytosolic protein release. It is found that FSNPs can deliver and release protein into cytosol for subcellular targeting as fast as 18 h post-delivery. Moreover, the delivery of molecular chaperone DJ-1 using FSNPs activates MAPK/ERK signaling of neural cells to protect cells from oxidative stress., (© 2021 Wiley-VCH GmbH.)

Numerous neurochemicals have been implicated in the modulation of brain function, making them appealing analytes for sensors and diagnostics. However, it is a grand challenge to selectively measure multiple neurochemicals simultaneously in vivo because of their great variations in concentrations, dynamic nature, and composition. Herein, we present a deep learning-based voltammetric sensing platform for the highly selective and simultaneous analysis of three neurochemicals in a living animal brain. The system features a carbon fiber electrode capable of capturing the mixed dynamics of a neurotransmitter, neuromodulator, and ions. Then a powerful deep neural network is employed to resolve individual chemical and spatial-temporal information. With this, a single electrochemical measurement reveals an interplaying concentration changes of dopamine, ascorbate, and ions in living rat brain, which is unobtainable with existing analytical methodologies. Our strategy provides a powerful means to expedite research in neuroscience and empower sensing-aided diagnostic applications., (© 2021 Wiley-VCH GmbH.)

Hydrogen-bonded organic frameworks (HOFs) are porous materials with great potential for biological applications. The self-assembly of HOFs and biomacromolecules, however, is challenging. We report herein the self-assembly of nanoscale HOFs (nHOFs) to encapsulate protein for intracellular biocatalysis. The self-assembly of tetrakis(4-amidiniumphenyl)methane and azobenzenedicarboxylate can encapsulate protein in situ to form protein@nHOFs under mild conditions. This strategy is applicable to proteins with different surface charge and molecular weight, showing a high protein encapsulation efficiency and minimal effect on protein activity. A cellular delivery study shows that the protein@TA-HOFs can efficiently enter cells and retain enzyme activity for biochemical catalysis in living cells for neuroprotection. Our strategy paves new avenues for interfacing nHOFs with biological settings and sheds light on expanding nHOFs as a platform for biomacromolecule delivery and disease treatment., (© 2021 Wiley-VCH GmbH.)

Recent innovations in genome editing have enabled the precise manipulation of the genetic information of mammalians, and benefitted the development of next-generation gene therapy. Despite these advances, several barriers to the clinical translation of genome editing remain, including the intracellular delivery of genome editing machinery, and the risk of off-target editing effect. Here, we review the recent advance of spatiotemporal delivery of CRISPR/Cas9 genome editing machinery, which is composed of programmable Cas9 nuclease and a single-guide RNA (sgRNA) using stimuli-responsive nanoparticles. We discuss the specific chemistries that have been used for controlled Cas9/sgRNA delivery and intracellular release in the presence of endogenous or external signals. These methodologies can leverage biological signals found locally within disease cells, or exogenous signals administrated with spatiotemporal control, through which an improved genome editing could be achieved. We also discuss the future in exploiting these approaches for fundamental biomedical applications and therapeutic genome editing., (© 2020 Wiley-VCH GmbH.)

Hierarchical self-assembly (HAS) is a powerful approach to create supramolecular nanostructures for biomedical applications. This potency, however, is generally challenged by the difficulty of controlling the HAS of biomacromolecules and the functionality of resulted HAS nanostructures. Herein, we report a modular approach for controlling the HAS of discrete metal-organic cages (MOC) into supramolecular nanoparticles, and its potential for intracellular protein delivery and cell-fate specification. The hierarchical coordination-driven self-assembly of adamantane-functionalized M 12 L 24 MOC (Ada-MOC) and the host-guest interaction of Ada-MOC with β-cyclodextrin-conjugated polyethylenimine (PEI-βCD) afford supramolecular nanoparticles in a controllable manner. HAS maintains high efficiency and orthogonality in the presence of protein, enabling the encapsulation of protein into the nanoparticles for intracellular protein delivery for therapeutic application and CRISPR/Cas9 genome editing., (© 2020 Wiley-VCH GmbH.)

Electrochemical sensing performance is often compromised by electrode biofouling (e.g., proteins nonspecific binding) in complex biological fluids; however, the design and construction of a robust biointerface remains a great challenge. Herein, inspired by nature, we demonstrate a robust polydopamine-engineered biointerfacing, to tailing zwitterionic molecules (i.e., sulfobetaine methacrylate, SBMA) through Michael Addition. The SBMA-PDA biointerface can resist proteins nonspecific binding in complex biological fluids while enhancing interfacial electron transfer and electrochemical stability of the electrode. In addition, this sensing interface can be integrated with tissue-implantable electrode for in vivo analysis with improved sensing performance, preserving ca. 92.0% of the initial sensitivity after 2 h of implantation in brain tissue, showing low acute neuroinflammatory responses and good stability both in normal and in Parkinson's disease (PD) rat brain tissue., (© 2020 Wiley-VCH GmbH.)

The development of new principles and techniques with high neuronal compatibility for quantitatively monitoring the dynamics of neurochemicals is essential for deciphering brain chemistry and function but remains a great challenge. We herein report a neuron-compatible method for in vivo neurochemical sensing by powering a single carbon fiber through spontaneous bipolar electrochemistry as a new sensing platform. By using ascorbic acid as a model target to prove the concept, we found that the single-carbon-fiber-powered microsensor exhibited a good response, high stability and, more importantly, excellent neuronal compatibility. The microsensor was also highly compatible with electrophysiological recording, thus enabling the synchronous recording of both chemical and electrical signals. The sensing principle could be developed for in vivo monitoring of various neurochemicals in the future by rationally designing and tuning the electrochemical reactions at the two poles of the carbon fiber., (© 2020 Wiley-VCH GmbH.)

The selective sensing of neurochemicals is essential for understanding the chemical basis of brain function and pathology. Interfacing the excellent recognition features of aptamers with in vivo compatible carbon fiber microelectrode (CFE)-based electroanalytical systems offers a plausible means to achieve this end. However, this is challenging in terms of coupling chemistry, stability, and versatility. Here, we present a new interfacial functionalization strategy based on the assembly of aptamer cholesterol amphiphiles (aptCAs) on the alkyl chain-functionalized CFE. The noncovalent cholesterol-alkyl chain interactions effectively immobilize aptamers onto the CFE surface, allowing the generation of a highly selective system for probing neurochemical dynamics in living systems and opening up a vast array of new opportunities for designing in vivo sensors for exploring brain chemistry., (© 2020 Wiley-VCH GmbH.)

Biological ion channels and ion pumps with sub-nanometer sizes modulate ion transport in response to external stimuli. Realizing such functions with sub-nanometer solid-state nanopores has been an important topic with wide practical applications. Herein, we demonstrate a biomimetic photoresponsive ion channel and photodriven ion pump using a porphyrin-based metal-organic framework membrane with pore sizes comparable to hydrated ions. We show that the molecular-size pores enable precise and robust optoelectronic ion transport modulation in a broad range of concentrations, unparalleled with conventional solid-state nanopores. Upon decoration with platinum nanoparticles to form a Schottky barrier photodiode, photovoltage across the membrane is generated with "uphill" ion transport from low concentration to high concentration. These results may spark applications in energy conversion, ion sieving, and artificial photosynthesis., (© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

DJ-1 protein deficiency caused by PARK7 gene mutation has been suggested to closely relate to Parkinson's disease (PD), mainly through the attenuation D2 dopamine receptor activity in mice; however, whether or how it affects the vesicular storage and exocytosis of neurochemicals remains unclear. By using electrochemical methods at a single vesicle/cell level with nano/micro-tip electrodes, we for the first time find that DJ-1 protein deficiency caused by PARK7 gene knockout (KO) in mice has little effect on vesicular catecholamine content but significantly prolongs the exocytotic events, especially the closing time of exocytotic fusion pores. Further studies suggest the inhibition of α-synuclein aggregation by DJ-1 protein might be one way that DJ-1 protein acts on neurotransmission. This finding offers the first direct link between DJ-1 protein deficiency and vesicular chemical storage and release of chemicals, providing a new chemical insight into the pathology of PD caused by PARK7 gene mutation., (© 2020 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A main challenge to broaden the biomedical application of CRISPR/Cas9 (clustered regularly interspaced short palindromic repeat (CRISPR) associated protein 9) genome editing technique is the delivery of Cas9 nuclease and single-guide RNA (sgRNA) into the specific cell and organ. An effective and very fast CRISPR/Cas9 genome editing in vitro and in vivo enabled by bioreducible lipid/Cas9 messenger RNA (mRNA) nanoparticle is reported. BAMEA-O16B, a lipid nanoparticle integrated with disulfide bonds, can efficiently deliver Cas9 mRNA and sgRNA into cells while releasing RNA in response to the reductive intracellular environment for genome editing as fast as 24 h post mRNA delivery. It is demonstrated that the simultaneous delivery of Cas9 mRNA and sgRNA using BAMEA-O16B knocks out green fluorescent protein (GFP) expression of human embryonic kidney cells with efficiency up to 90%. Moreover, the intravenous injection of BAMEA-O16B/Cas9 mRNA/sgRNA nanoparticle effectively accumulates in hepatocytes, and knocks down proprotein convertase subtilisin/kexin type 9 level in mouse serum down to 20% of nontreatment. The leading lipid nanoparticle, BAMEA-O16B, represents one of the most efficient CRISPR/Cas9 delivery nanocarriers reported so far, and it can broaden the therapeutic promise of mRNA and CRISPR/Cas9 technique further., (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Spreading depolarization (SD) occurs frequently in the injured brain, and its neurochemical effects are detrimental to brain function. We report the first observation that the release of ascorbate, an important neurochemical in the brain, is closely accompanied with SD. Ascorbate was monitored with carbon nanotube (CNT)-sheathed carbon fiber microelectrodes (CFEs). This system features high selectivity and temporal/spatial resolution. With our sensor, we observed a significant increase in the concentration of ascorbate in response to SD induction. Mechanistic studies show a contrasting behavior; with a SD specific inhibitor, release was completely suppressed, whereas with inhibition of commonly employed glutamate transporters, ascorbate release was increased, demonstrating a powerful means of discriminating ascorbate release between disputed pathways. Most importantly, we observed the propagative nature of ascorbate release following SD., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

N 6 -Methyladenosine (m 6 A) represents a common and highly dynamic modification in eukaryotic RNA that affects various cellular pathways. Natural dioxygenases such as FTO and ALKBH5 are enzymes that demethylate m 6 A residues in mRNA. Herein, the first identification of a small-molecule modulator that functions as an artificial m 6 A demethylase is reported. Flavin mononucleotide (FMN), the metabolite produced by riboflavin kinase, mediates substantial photochemical demethylation of m 6 A residues of RNA in live cells. This study provides a new perspective to the understanding of demethylation of m 6 A residues in mRNA and sheds light on the development of powerful small molecules as RNA demethylases and new probes for use in RNA biology., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Studies on the adsorption and transport of water molecules with oxidized two-dimensional (2 D) carbon materials have attracted increasing interest owing to their wide range of applications, such as sensing, energy conversion, and membrane separation. In this contribution, the interaction between water molecules and oxidized 2 D carbon materials (i.e., graphene oxide and graphdiyne oxide) is discussed, the influence of water adsorption and transport on the physicochemical properties of 2 D carbon materials is presented, and the recent progress on oxidized 2 D carbon material-based proton conduction, electricity generation, water transport, and humidity sensing is highlighted. The opportunities and challenges in these research fields are discussed, especially the structural stability and chemical modification of 2 D carbon materials., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The two-dimensional carbon material graphdiyne (GDY) holds great promise as a semiconductor and porous material, however, exfoliation of bulk GDY into single- or few-layered GDY in the aqueous phase remains a challenge. We report an efficient method for the damage-free exfoliation of bulk GDY into single- or few-layered GDY with high yield in an aqueous solution of inorganic salts (e.g., Li 2 SiF 6 ). This was confirmed by spherical-aberration-corrected scanning transmission electron microscopy, scanning/transmission electron microscopy, atomic force microscopy, Fourier transform infrared/Raman spectroscopy, X-ray photoelectron spectroscopy. The method gives high exfoliation efficiency (75 wt %) without creating additional structural defects or oxides in the exfoliated GDY. Theoretical calculations suggest that non-covalent adsorption of the anion, diffusion of the cation, and subsequent repulsive forces between adjacent flakes are the main driving force for the efficient exfoliation., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A nonintuitive observation of monovalent anion-induced ion current rectification inversion at polyimidazolium brush (PimB)-modified nanopipettes is presented. The rectification inversion degree is strongly dependent on the concentration and species of monovalent anions. For chaotropic anions (for example, ClO 4 - ), the rectification inversion is easily observed at a low concentration (5 mm), while there is no rectification inversion observed for kosmotropic anions (Cl - ) even at a high concentration (1 m). Moreover, at the specific concentration (for example, 10 mm), the variation of rectification ratio on the type of anions is ranged by Hofmeister series (Cl - ≥NO 3 - >BF 4 - >ClO 4 - >PF 6 - >Tf 2 N - ). Estimation of the electrokinetic charge density (σ ek ) demonstrates that rectification inversion originates from the charge inversion owing to the over-adsorption of chaotropic monovalent anion. To qualitatively understand this phenomenon, a concentration-dependent adsorption mechanism is proposed., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Graphdiyne oxide (GDO), the oxidized form of graphdiyne (GDY), exhibits an ultrafast humidity response with an unprecedented response speed (ca. 7 ms), which is three times faster than that of graphene oxide (GO) with the same thickness and O/C ratio. The ultrafast humidity response of GDO is considered to benefit from the unique carbon hybridization of GDO, which contains acetylenic bonds that are more electron-withdrawing than ethylenic bonds in GO, consequently giving rise to a faster binding rate with water. This distinctive structure-based property enables the fabrication of a novel GDO-based humidity sensor with an ultrafast response speed and good selectivity against other kinds of gas molecules as well as high sensitivity. These properties allow the sensor to accurately monitor the respiration rate change of human and hypoxic rats., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Resisting biomolecule adsorption onto the surface of brain-implanted microelectrodes is a key issue for in vivo monitoring of neurochemicals. Herein, we demonstrate that an ultrathin cell-membrane-mimic film of ethylenedioxythiophene tailored with zwitterionic phosphorylcholine (EDOT-PC) electropolymerized onto the surface of a carbon fiber microelectrode (CFE) not only resists protein adsorption but also maintains the sensitivity and time response for in vivo monitoring of dopamine (DA). As a consequence, the as-prepared PEDOT-PC/CFEs could be used as a new reliable platform for tracking DA in vivo and would help understand the physiological and pathological functions of DA., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

We report a facile and general approach to the formation of bimetallic core-shell Au@Ag nanoparticles (NPs) immobilized to metal-organic frameworks (MOFs) via a one-step synthetic route at room temperature. Dopamine (DA) is used as a moderate reductant, which can bind to negatively charged groups of MOFs through electrostatic interaction, and subsequently Au@Ag core-shell NPs are formed by in-situ reduction of the bimetallic Au and Ag precursors step-by-step spontaneously without pre-synthesized seeds. The as-formed Au@Ag core-shell NPs immobilized to MOFs exhibit excellent catalytic activity for the reduction of 4-nitrophenol (4-NPh) by NaBH 4 to 4-aminophenol (4-APh) due to a synergistic effect and are highly stable as demonstrated by recycling experiments., (© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Gold nanoparticle (Au-NP)-based colorimetric assays offer new opportunitites for the visualization and quantification of neurochemicals involved in physiological and pathological processes due to their high sensitivity, designability, and low technical demands. In this Research News, we systematically review the advances on the development of Au-NP-based colorimetric methods for visualization and quantification of neurochemicals and their potential applications for effectively monitoring neurochemicals in the central nervous system. By integration of the favourable surface chemistry with the high extinction coefficient of Au-NPs, some new principles and methods could be developed for the quantification of neurochemicals involved in brain functions. New strategies to design the surface chemistry of Au-NPs, along with the key challenges yet to be addressed to achieve online visualization and quantification of neurochemicals in the central nervous system, are illustrated and discussed. The questions opened here should inspire future investigations and lead to discoveries that continue the development of the effective analytical protocols based on Au-NPs for neurochemical visualization and quantification., (© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

In this work, investigation of the comparative influence of diverse ionic liquids (ILs) as electrolyte additives on the chiral separation of dansylated amino acids by using Zn(II)-L-arginine complex mediated chiral ligand exchange CE (CLE-CE) was conducted. It has been found that not only the varied substituted group number, but also the alkyl chain length of the substituted group on imidazole ring in the structure of ILs show different influence on chiral separation of the analytes in the CLE-CE system, which could be understood by their direct influence on EOF. Meanwhile, the variation of anion in the structure of ILs displayed remarkably changed performance and the ILs with Cl(-) showed the most obvious promoting effect on the chiral separation performance. Among the investigated seven ILs, 1-butyl-3-methylimidazolium chloride was validated to be the proper electrolyte additive in the CLE-CE system. Moreover, it has been observed that 1-butyl-3-methylimidazolium chloride also has obvious promotive effect on the labeling performance. The results have demonstrated that the ILs with different structures have important relation to their performance in CLE-CE and to their labeling efficiency in dansylation of the analytes., (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Amino acid ionic liquids (AAILs) with L-lysine (L-Lys) as anion were synthesized and applied as new chiral ligands in Zn(II) complexes for chiral ligand-exchange CE. After effective optimization, baseline enantioseparation of seven pairs of dansylated amino acids was achieved with a buffer of 100.0 mM boric acid, 5.0 mM ammonium acetate, 3.0 mM ZnSO4 , and 6.0 mM [C6 mim][L-Lys] at pH 8.2. To validate the unique behavior of AAILs, a comparative study between the performance of Zn(II)-L-Lys and Zn(II)-[C6 mim][L-Lys] systems was conducted. In Zn(II)-[C6 mim][L-Lys] system, it has been found that the improved chiral resolution could be obtained and the migration times of the three test samples were markedly prolonged. Then the separation mechanism was further discussed. The role of [C6 mim][L-Lys] indicated clearly that the synthesized AAILs could be used as chiral ligands and would have potential utilization in separation science in future., (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The development of magnetic nanoparticles with multiple functions has been an ever-growing field because of their diverse applications in drug delivery, biosensing, cell labeling, and so on. In this study, a facile method was developed to construct multifunctional magnetic nanocomposites. The approach is based on the use of poly(glycidyl methacrylate), PGMA, with numerous epoxy groups as reactive polymer to combine with fluorescent dye, the surface of magnetic nanoparticles, and targeting ligands directly without expatiatory functionality design. The resultant nanocomposites with good superparamagnetic and fluorescent properties could be exploited for bioimaging. Moreover, after conjugation with a model protein, namely, transferrin, which specifically targets cells overexpressing transferrin receptors, the nanocomposites could be used selectively to recognize Hela cells in comparison with nonconjugated ones. These results indicate that the newly designed magnetic nanocomposites with PGMA as functional polymer could serve as a novel versatile platform to conjugate with various molecules for construction of diverse multifunctional magnetic nanocomposites to meet different requirements and potential uses in nanomedicine and biological chemistry., (Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Over the last couple of decades, researchers have developed diverse chiral separation methods emerged from a few chiral separation principles. This review article is primarily focused on the application of chiral ligand-exchange (CLE) principle in capillary electromigration techniques, such as capillary electrophoresis (CE) and capillary electrochromatography (CEC). First, the most commonly used CLE-CZE separation mode by using different kinds of central ions, such as Cu(II), Zn(II), borate ion, and other metal ions, has been introduced. Meanwhile, several kinds of surfactants have been applied as the micelle-forming agents in the CLE micellar electrokinetic chromatography mode. The highlight of recent research of CLE-CEC is the exploitation of novel columns for chiral separation. Then, two kinds of capillary columns, packed capillary and monolithic capillary column, have been briefly described. Finally, the effective application of these chiral separation methods has been presented, including the application in life science and food analysis area., (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Exposure to aromatic amines from different industrial and agricultural activities entails a substantial risk of deleterious somatic effects, genetic damage and cancer development. Thus, a new and simple method for separation and analysis of aromatic amines has been developed by open-tubular capillary electrochromatography with a novel amphipathic block copolymer (poly(tert-butyl acrylate)(127)-block-poly(glycidyl methacrylate)(86)) coating based on its self-assembled property. Key factors affecting the separation efficiency of the test analytes, such as pH, buffer concentration and selective solvent, were studied in detail. Meanwhile, method validation was well evaluated by linearity (≥0.998), detection limit and recovery. Application of this developed protocol on in vitro monitoring of the target aromatic amines distribution in rat blood demonstrated its potential usage for separation and determination of aromatic amines in biological samples. Additionally, for assimilating more polymeric materials into analysis of aromatic amines, the effect of morphology changes of the amphipathic block copolymer coating on open-tubular capillary electrochromatography separation was also studied, and the result revealed that the block copolymer coating could play the same role as surfactant., (Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

An acid barrage stacking (ABS) method has been shown to be feasible for online anti-salt injection in CE of 9-fluorenylmethyl chloroformate (FMOC)-labeled amino acids (AAs) detected by common UV absorption. The operation was performed on normal polar CE by sucking in an extra plug of acid following a sample zone, serving as a selective acid barrage to block the backward migration of weak anionic analytes due to a sudden mobility reduction via acid-base reaction which does not affect strong co-ions such as Cl(-) to penetrate the barrage freely. By CE-UV of FMOC-AAs in various NaCl solutions, the effectiveness of ABS was firmly validated, able to stand up to 500 mM NaCl and to stack analytes by 10(3)-fold calculated from the UV detection limits, that is 0.01 microM for ABS and 10 microM for non-stacking injection. The method was also validated by determining trace Glu and Asp in real samples of rat brain microdialysate, rat serum and human saliva. The intraday RSDs were 0.33-4.9% for migration time and 1.8-9.6% for peak area. The recoveries measured by spiking technique were 82-115% for Glu and 86-116% for Asp. Working equations were obtained by plotting peak height vs. concentration at 0.1-50 microM, with correlation coefficients of >0.999. The contents of Glu and Asp were thus found at 0.26-0.83 microM and 0.24-0.64 microM respectively, in rat brain microdialyste; 37-40 microM and 8.4-10 microM, respectively, in rat serum; and 3.5-5.8 microM and 1.0-4.1 microM, respectively in human saliva. They were consistent with the data from other methods.

A low-cost tunable chiral ion-exchange capillary electrochromatographic method has been developed for the separation of arylglycine amide racemic mixtures with dextran sulfate (DS) as an anionic and chiral pseudostationary phase and Tris-tartrate as a buffer system. The concentrations of DS and Tris had opposite influences on retention and resolution and could serve as ideal factors to finely tune the running speed and chiral resolution. Tartrate and pH largely impact the separation but pH should be confined within 3.0-5.5, only suitable for coarse tuning, while tartrate was preserved as the key buffering reagent, normally maintained at 40 mmol/L. With a working system composed of 0.1-1.0% DS, 20-60 mmol/L Tris, and 40 mmol/L tartrate at pH 3.50-4.50, the enantioresolution of arylglycine amides was shown to be dependent on their chemical structure: The chiral resolution increased when the hydrogen at the alpha-amino group or at the p-position of phenyl ring was replaced by other larger group(s) but the resolution decreased when the group at the o- or m-site on the phenyl ring was enlarged. Further, the electronegative substitute of -Cl had larger resolution increment than methyl or methoxy at the position p- of phenyl ring but much lower increment at position m-. It is possible to well explain the resolution variation phenomenon by considering the group resistance and the variation of hydrogen-bonds formed inside the amino amides and between the solutes and DS. The amido group was shown irreplaceable to have chiral resolution with DS alone as an ionic and chiral pseudostationary phase.