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Airborne nanoplastics can enter alveolar cells and trigger intracellular oxidative stress primarily. Herein, taking advantage of the high electrochemical resolution of SiC@Pt nanoelectrodes, we achieved the quantitative discrimination of the major ROS/RNS within A549 cells, disclosed the sources of their precursors, and observed that the NO (RNS precursor) level significantly increased, whereas O 2 ˙ - (ROS precursor) remained relatively stable during the nanoplastics exposure. This establishes that iNOS or mitochondrion-targeted treatment may be a preventive or therapeutic strategy for nanoplastic-induced lung injury.

Vascular endothelial cells (ECs) are natively exposed to dynamic cyclic stretch and respond to it by the production of vasoactive molecules. Among them, reactive oxygen species (ROS) are closely implicated to the endothelial function and vascular homeostasis. However, the dynamic monitoring of ROS release during endothelial mechanotransduction remains a steep challenge. Herein, we developed a stretchable electrochemical sensor by decoration of uniform and ultrasmall platinum nanoparticles (Pt NPs) on gold nanotube (Au NT) networks (denoted as Au@Pt NTs). The orchestrated structure exhibited prominent electrocatalytic property toward the oxidation of hydrogen peroxide (H 2 O 2 ) (as the most stable ROS) while maintaining excellent mechanical compliance of Au NT networks. Moreover, the favorable biocompatibility of Au NTs and Pt NPs promoted the adhesion and proliferation of ECs cultured thereon. These allowed in situ inducing ECs mechanotransduction and synchronously real-time monitoring of H 2 O 2 release. Further investigation revealed that the production of H 2 O 2 was positively correlated with the applied mechanical strains and could be boosted by other coexisting pathogenic factors. This indicates the great prospect of our proposed sensor in exploring ROS-related signaling for the deep understanding of cell mechanotransduction and vascular disorder.

Mitochondria are believed to be the major source of intracellular reactive oxygen species (ROS). However, in situ, real-time and quantitative monitoring of ROS release from mitochondria that are present in their cytosolic environment remains a great challenge. In this work, a platinized SiC@C nanowire electrode is placed into a single cell for in situ detection of ROS signals from intracellular mitochondria, and antineoplastic agent (paclitaxel) induced ROS production is successfully recorded. Further investigations indicate that complex IV (cytochrome c oxidase, COX) is the principal site for ROS generation, and significantly more ROS are generated from mitochondria in cancer cells than that from normal cells. This work provides an effective approach to directly monitor intracellular mitochondria by nanowire electrodes, and consequently obtains important physiological evidence on antineoplastic agent-induced ROS generation, which will be of great benefit for better understanding of chemotherapy at subcellular levels., (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The existence of a homeostatic mechanism regulating reactive oxygen/nitrogen species (ROS/RNS) amounts inside phagolysosomes has been invoked to account for the efficiency of this process but could not be unambiguously documented. Now, intracellular electrochemical analysis with platinized nanowire electrodes (Pt-NWEs) allowed monitoring ROS/RNS effluxes with sub-millisecond resolution from individual phagolysosomes impacting onto the electrode inserted inside a living macrophage. This shows for the first time that the consumption of ROS/RNS by their oxidation at the nanoelectrode surface stimulates the production of significant ROS/RNS amounts inside phagolysosomes. These results establish the existence of the long-postulated ROS/RNS homeostasis and allows its kinetics and efficiency to be quantified. ROS/RNS concentrations may then be maintained at sufficiently high levels for sustaining proper pathogen digestion rates without endangering the macrophage internal structures., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Nanoelectrodes allow precise and quantitative measurements of important biological processes at the single living-cell level in real time. Cylindrical nanowire electrodes (NWEs) required for intracellular measurements create a great challenge for achieving excellent electrochemical and mechanical performances. Herein, we present a facile and robust solution to this problem based on a unique SiC-core-shell design to produce cylindrical NWEs with superior mechanical toughness provided by the SiC nano-core and an excellent electrochemical performance provided by the ultrathin carbon shell that can be used as such or platinized. The use of such NWEs for biological applications is illustrated by the first quantitative measurements of ROS/RNS in individual phagolysosomes of living macrophages. As the shell material can be varied to meet any specific detection purpose, this work opens up new opportunities to monitor quantitatively biological functions occurring inside cells and their organelles., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The glutathione (GSH) system is one of the most powerful intracellular antioxidant systems for the elimination of reactive oxygen species (ROS) and maintaining cellular redox homeostasis. However, the rapid kinetics information (at the millisecond to the second level) during the dynamic antioxidation process of the GSH system remains unclear. As such, we specifically developed a novel dual‐wire nanosensor (DWNS) that can selectively and synchronously measure the levels of GSH and ROS with high temporal resolution, and applied it to monitor the transient ROS generation as well as the rapid antioxidation process of the GSH system in individual cancer cells. These measurements revealed that the glutathione peroxidase (GPx) in the GSH system is rapidly initiated against ROS burst in a sub‐second time scale, but the elimination process is short‐lived, ending after a few seconds, while some ROS are still present in the cells. This study is expected to open new perspectives for understanding the GSH antioxidant system and studying some redox imbalance‐related physiological. [ABSTRACT FROM AUTHOR]

Main observation and conclusion: Parkinson's disease (PD) is one of the most common neurogenerative diseases (NDDs), characterized as less neurotransmitter release and loss of dopaminergic (DAergic) neurons with microglial inflammatory response as a key player. Natural product harpagide with anti‐inflammatory function is a potential therapeutic drug of PD, but its role towards microglial activation and inflammation‐mediated neuronal injury remained unsure. In this work, taking advantage of nanoelectrode amperometry with high temporal‐spatial resolution, we used nanowire electrodes (NWEs) to monitor intracellular reactive oxygen species (ROS) level and carbon fiber nanoelectrodes (CFNEs) to detect synaptic dopamine exocytosis, to explore the effect of harpagide in modulating microglial inflammatory reaction and protecting DAergic neurons in neuron‐microglia co‐culture system. The results indicate that harpagide inhibits microglia from activation induced by LPS/IFN‐γ and generation of ROS, therefore reduces inflammation‐mediated neural injury and maintains dopamine exocytosis function. These conclusions establish that harpagide possesses promising avenues for preventive or therapeutic interventions against PD and other NDDs. [ABSTRACT FROM AUTHOR]

The existence of a homeostatic mechanism regulating reactive oxygen/nitrogen species (ROS/RNS) amounts inside phagolysosomes has been invoked to account for the efficiency of this process but could not be unambiguously documented. Now, intracellular electrochemical analysis with platinized nanowire electrodes (Pt‐NWEs) allowed monitoring ROS/RNS effluxes with sub‐millisecond resolution from individual phagolysosomes impacting onto the electrode inserted inside a living macrophage. This shows for the first time that the consumption of ROS/RNS by their oxidation at the nanoelectrode surface stimulates the production of significant ROS/RNS amounts inside phagolysosomes. These results establish the existence of the long‐postulated ROS/RNS homeostasis and allows its kinetics and efficiency to be quantified. ROS/RNS concentrations may then be maintained at sufficiently high levels for sustaining proper pathogen digestion rates without endangering the macrophage internal structures. [ABSTRACT FROM AUTHOR]

Nanoelectrodes allow precise and quantitative measurements of important biological processes at the single living-cell level in real time. Cylindrical nanowire electrodes (NWEs) required for intracellular measurements create a great challenge for achieving excellent electrochemical and mechanical performances. Herein, we present a facile and robust solution to this problem based on a unique SiC-core-shell design to produce cylindrical NWEs with superior mechanical toughness provided by the SiC nano-core and an excellent electrochemical performance provided by the ultrathin carbon shell that can be used as such or platinized. The use of such NWEs for biological applications is illustrated by the first quantitative measurements of ROS/RNS in individual phagolysosomes of living macrophages. As the shell material can be varied to meet any specific detection purpose, this work opens up new opportunities to monitor quantitatively biological functions occurring inside cells and their organelles. [ABSTRACT FROM AUTHOR]

Main observation and conclusion: Parkinson's disease (PD) is one of the most common neurogenerative diseases (NDDs), characterized as less neurotransmitter release and loss of dopaminergic (DAergic) neurons with microglial inflammatory response as a key player. Natural product harpagide with anti‐inflammatory function is a potential therapeutic drug of PD, but its role towards microglial activation and inflammation‐mediated neuronal injury remained unsure. In this work, taking advantage of nanoelectrode amperometry with high temporal‐spatial resolution, we used nanowire electrodes (NWEs) to monitor intracellular reactive oxygen species (ROS) level and carbon fiber nanoelectrodes (CFNEs) to detect synaptic dopamine exocytosis, to explore the effect of harpagide in modulating microglial inflammatory reaction and protecting DAergic neurons in neuron‐microglia co‐culture system. The results indicate that harpagide inhibits microglia from activation induced by LPS/IFN‐γ and generation of ROS, therefore reduces inflammation‐mediated neural injury and maintains dopamine exocytosis function. These conclusions establish that harpagide possesses promising avenues for preventive or therapeutic interventions against PD and other NDDs. [ABSTRACT FROM AUTHOR]

Reactive oxygen species (ROS) and nicotinamide adenine dinucleotide (NADH) are important intracellular redox-active molecules involved in various pathological processes including inflammation, neurodegenerative diseases, and cancer. However, the fast dynamic changes and mutual regulatory kinetic relationship between intracellular ROS and NADH in these biological processes are still hard to simultaneously investigate. A dual-channel nanowire electrode (DC-NWE) integrating two conductive nanowires, one functionalized with platinum nanoparticles and the other with conductive polymer, was nanofabricated for the selective and simultaneous real-time monitoring of intracellular ROS and NADH release by mitochondria in single living MCF-7 tumoral cells stimulated by resveratrol. The production of ROS was observed to occur tenths of a second before the release of NADH, a significant new piece of information suggesting a mechanism of action of resveratrol. Beyond the importance of the specific data gathered in this study, this work established the feasibility of simultaneously monitoring multiple species and analyzing their kinetics relationships over sub-second time scales thanks to dual-channel nanowire electrodes. It is believed that this concept and its associated nanoelectrochemical tools might benefit to a deeper understanding of mutual regulatory relationship between intracellular crucial molecular markers during physiological and pathological processes as well as for evaluating medical treatments. [Display omitted] • We propose a novel strategy for developing a dual-channel nanowire electrode (DC-NWE). • DC-NWE has been used for selective and simultaneous monitoring of ROS and NADH in single cells stimulated by resveratrol. • The production of ROS was observed to occur tenths of a second before NADH release. • This work presented the feasibility of simultaneously monitoring multiple species and analyzing their kinetics difference. [ABSTRACT FROM AUTHOR]