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Nano Research
Journal Prestige (SJR): 3.064  Citation Impact (citeScore): 8 Number of Followers: 4  Hybrid journal (It can contain Open Access articles)ISSN (Print) 1998-0000 - ISSN (Online) 1998-0124 Published by Springer-Verlag  [2469 journals]
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- Novel metastable Bi:Co and Bi:Fe alloys nanodots@carbon as anodes for high
rate K-ion batteries-
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Abstract: Bi is a promising anode material for potassium-ion batteries (PIBs) due to its high theoretical capacity. However, severe pulverization upon cycling limits its practical applications. In this work, we propose a new approach of using metastable alloys with Bi elements. Metastable Bi:Co and Bi:Fe alloys nanodots@carbon anode materials (Bi:Co and Bi:Fe@C) are synthesized for the first time via simple annealing of their metal-organic frameworks (MOF) precursors. These prepared materials are demonstrated as ideal hosts for high-rate K-ion storage. Bi0.85Co0.15@C and Bi0.83Fe0.17@C electrodes respectively deliver superior 178 and 253 mAh·g−1 at 20 A·g−1, as well as stable cycling performance at 2 A·g−1. Ex situ scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and transmission electron microscopy (TEM) studies on Bi:Co@C indicate that the elemental Co separates out during the initial potassiation and stands during the following discharge/charge cycles. In situ formed Co precipitates can act as (1) “conductive binders” as well as (2) “separators” to prevent the severe aggregation of adjacent active elemental Bi nanoparticles and (3) accelerate the potassiation/de-potassiation kinetics in elemental Bi precipitates after initial discharge/charge cycles. This work could inspire the development of metal-type anodes.
PubDate: 2022-05-20
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- Focus on using nanopore technology for societal health, environmental, and
energy challenges-
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Abstract: With an increasing global population that is rapidly ageing, our society faces challenges that impact health, environment, and energy demand. With this ageing comes an accumulation of cellular changes that lead to the development of diseases and susceptibility to infections. This impacts not only the health system, but also the global economy. As the population increases, so does the demand for energy and the emission of pollutants, leading to a progressive degradation of our environment. This in turn impacts health through reduced access to arable land, clean water, and breathable air. New monitoring approaches to assist in environmental control and minimize the impact on health are urgently needed, leading to the development of new sensor technologies that are highly sensitive, rapid, and low-cost. Nanopore sensing is a new technology that helps to meet this purpose, with the potential to provide rapid point-of-care medical diagnosis, real-time on-site pollutant monitoring systems to manage environmental health, as well as integrated sensors to increase the efficiency and storage capacity of renewable energy sources. In this review we discuss how the powerful approach of nanopore based single-molecule, or particle, electrical promises to overcome existing and emerging societal challenges, providing new opportunities and tools for personalized medicine, localized environmental monitoring, and improved energy production and storage systems.
PubDate: 2022-05-20
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- Nanomechanical assay for ultrasensitive and rapid detection of SARS-CoV-2
based on peptide nucleic acid-
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Abstract: The massive global spread of the COVID-19 pandemic makes the development of more effective and easily popularized assays critical. Here, we developed an ultrasensitive nanomechanical method based on microcantilever array and peptide nucleic acid (PNA) for the detection of severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) RNA. The method has an extremely low detection limit of 0.1 fM (105 copies/mL) for N-gene specific sequence (20 bp). Interestingly, it was further found that the detection limit of N gene (pharyngeal swab sample) was even lower, reaching 50 copies/mL. The large size of the N gene dramatically enhances the sensitivity of the nanomechanical sensor by up to three orders of magnitude. The detection limit of this amplification-free assay method is an order of magnitude lower than RT-PCR (500 copies/mL) that requires amplification. The non-specific signal in the assay is eliminated by the in-situ comparison of the array, reducing the false-positive misdiagnosis rate. The method is amplification-free and label-free, allowing for accurate diagnosis within 1 h. The strong specificity and ultra-sensitivity allow single base mutations in viruses to be distinguished even at very low concentrations. Also, the method remains sensitive to fM magnitude lung cancer marker (miRNA-155). Therefore, this ultrasensitive, amplification-free and inexpensive assay is expected to be used for the early diagnosis of COVID-19 patients and to be extended as a broad detection tool.
PubDate: 2022-05-19
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- Metformin capped Cu2(OH)3Cl nanosheets for chemodynamic wound disinfection
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Abstract: Recently, the development of chemodynamic therapy (CDT) offers a potential approach for fighting bacteria and treating infectious diseases, in which those CDT nanoagents can catalyze the generation of hydroxyl radicals (•OH) to destroy bacteria. In this work, to improve the efficiency of CDT, we have designed a new kind of metformin (Met)-capped two-dimensional Cu2(OH)3Cl nanosheets (CuOHCl-Met NSs) with good monodispersity, highly positive charge, and good biocompatibility for improving antibacterial effect and accelerating wound healing. With the capped Met, CuOHCl-Met NSs can effectively kill bacteria under a low concentration (6 µg·mL−1) and a short treatment time (in 15 min), showing great advantages over the counterpart without Met. In vivo results demonstrated that CuOHCl-Met NSs accelerated the tissue regeneration of staphylococcus aureus-infected dermal wounds. This study provides a new pathway for improving efficiency of CDT nanoagent through using old drug.
PubDate: 2022-05-19
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- Memristive structure of Nb/HfOx/Pd with controllable switching mechanisms
to perform featured actions in neuromorphic networks-
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Abstract: All memristor neuromorphic networks have great potential and advantage in both technology and computational protocols for artificial intelligence. It is crucial to find suitable elementary units for both performing featured neuromorphic functions and fabrication in large scale. Here a simple memristive structure, Nb/HfOx/Pd, is proposed for this goal. Its two resistive switching mechanisms, Mott transition of NbO2 and oxygen vacancy (Vo) migration, can be controlled by modulating external bias directions. Negative bias activates reversible phase transition and restrains Vo filament formation to allow the memristor to mimic the firing action potential. Positive bias activates Vo filament formation and restrains the other to allow the memristor to mimic synaptic plasticity and learning protocols. The system can respond adaptively to naturally generated action potentials and modified synaptic signals from the same memristive structure. In addition, some special features related to signal encoding and recognition are discovered when the system is settled according to chaos circuit theory. Our study provides a novel approach for designing elementary units for neuromorphic computations.
PubDate: 2022-05-19
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- Polydopamine-assisted in-situ formation of dense MOF layer on polyolefin
separator for synergistic enhancement of lithium-sulfur battery-
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Abstract: The separator is of great significance to alleviate the shuttle effect and dendrite growth of lithium-sulfur batteries. However, most of the current commercial separators cannot meet these requirements well. In this work, a dense metal-organic-framework (MOF) modification layer is in-situ prepared by the assistant of polydopamine on the polypropylene separators. Due to the unique structure and synergistic effect of polydopamine (PDA) and zeolitic imidazolate framework-8 (ZIF-8), the functional separator can not only trap the polysulfides effectively but also promote the transport of lithium ions. As a result, the battery assembled with the functional separator exhibits excellent cycle stability. The capacity remains 711 mAh·g−1 after 500 cycles at 2 C, and the capacity decay rate is as low as 0.013% per cycle. The symmetrical battery is cycled for 1,000 h at 2 mA·cm2 (2 mAh·cm−2) with the plating/stripping overpotential of 20 mV. At the same time, the modification separator shows a higher lithium ion transference number (0.88), better thermal stability and electrolyte wettability than the unmodified separator.
PubDate: 2022-05-19
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- Improving stability of MXenes
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Abstract: Due to their superior hydrophilicity and conductivity, ultra-high volumetric capacitance, and rich surface-chemistry properties, MXenes exhibit unique and excellent performance in catalysis, energy storage, electromagnetic shielding, and life sciences. Since they are derived from ceramics (MAX phase) through etching, one of the challenges in MXenes preparation is the inevitable exposure of metal atoms on their surface and embedding of anions and cations. Because the as-obtained MXenes are always in a thermodynamically metastable state, they tend to react with trace oxygen or oxygen-containing groups to form metal oxides or degrade, leading to sharply declined activity and impaired performance. Therefore, improving the stability of MXenes-based materials is of practical significance in relevant applications. Unfortunately, there lacks a comprehensive review in the literature on relevant topics. To help promote the wide applications of MXenes, we review from the following aspects: (i) insights into the factors affecting the stability of MXenes-based materials, including oxidation of MXenes flakes, stability of MXenes colloidal solutions, and swelling and degradation of MXenes thin-film, (ii) strategies for enhancing the stability of MXenes-based materials by optimizing MAX phase synthesis and modifying the MXenes preparation, and (iii) techniques for further increasing the stability of freshly prepared MXenes-based materials via controlling the storage conditions, and forming shielding on the surface and/or edge of MXenes flakes. Finally, some outlooks are proposed on the future developments and challenges of highly active and stable MXenes. We aim to provide guidance for the design, preparation, and applications of MXenes-based materials with excellent stability and activity.
PubDate: 2022-05-19
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- A topology framework for macromolecular complexes and condensates
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Abstract: Macromolecular assemblies such as protein complexes and protein/RNA condensates are involved in most fundamental cellular processes. The arrangement of subunits within these nano-assemblies is critical for their biological function and is determined by the topology of physical contacts within and between the subunits forming the complex. Describing the spatial arrangement of these interactions is of central importance to understand their functional and stability consequences. In this concept article, we propose a circuit topology-based formalism to define the topology of a complex consisting of linear polymeric chains with inter- and intrachain interactions. We apply our method to a system of model polymer chains as well as protein assemblies. We show that circuit topology can categorize different forms of chain assemblies. Our multi-chain circuit topology should aid analysis and predictions of mechanistic and evolutionary principles in the design of macromolecular assemblies.
PubDate: 2022-05-19
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- Constructing stable Li-solid electrolyte interphase to achieve
dendrites-free solid-state battery: A nano-interlayer/Li pre-reduction
strategy-
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Abstract: Solid-state batteries based on Li and nonflammable solid-state electrolytes (SSEs) have aroused the attention of numerous researchers because of their absolute safety and potentially high energy density. Most SSEs after coming into contact with Li are reduced, which leads to high interfacial charge-transfer impedance and dendrites formation. In this study, an “interlayer-Li pre-reduction strategy” was proposed to solve the above problem of reduction. An intermediate layer was introduced between solid electrolyte and Li, and it reacted with Li to produce a stable and ion-conductive interphase. Cubic garnet-type Nb-doped Li7La3Zr2O12 (Nb-LLZO) was selected as an example solid electrolyte since it is characterized by high ionic conductivity, feasible preparation under ambient conditions, as well as low cost. The high impedance arising from the reduction at the Nb-LLZO∣Li interface has limited its application. In this paper, a nano-scale Li phosphorus oxynitride (LiPON) layer was deposited on the Nb-LLZO pellets through radio frequency (RF) magnetron sputtering, which pre-reacted with Li in-situ to produce a lithiophilic, electronically insulating, and ionic conductive interphase. The produced interphase significantly inhibited the reduction of Nb5+ against Li and the formation and propagation of Li dendrites. It is noteworthy that Li∣LiPON∣Nb-LLZO∣LiPON∣Li cells stably cycled for over 2,000 h without any short circuit. This study emphasizes and demonstrates the significance of the pre-conversion of modification layer between unstable SSE and Li metal to improve interfacial stability.
PubDate: 2022-05-19
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- High-performance solar-blind photodetector arrays constructed from
Sn-doped Ga2O3 microwires via patterned electrodes-
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Abstract: Ga2O3 has been regarded as a promising material for solar-blind detection due to its ultrawide bandgap and low growth cost. Although semiconductor microwires (MWs) possess unique optical and electronic characteristics, the performances of photodetectors developed from Ga2O3 MWs are still less than satisfactory. Herein, we demonstrate high-performance solar-blind photodetectors based on Sn-doped Ga2O3 MWs, possessing a light/dark current ratio of 107 and a responsivity of 2,409 A/W at 40 V. Moreover, a 1 × 10 solar-blind photodetector linear array is developed based on the Sn-doped Ga2O3 MWs via a patterned-electrodes method. And clear solar-blind images are obtained by using the photodetector array as the imaging unit of a solar-blind imaging system. The results provide a convenient way to construct high-performance solar-blind photodetector arrays based on Ga2O3 MWs, and thus may push forward their future applications.
PubDate: 2022-05-19
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- Pd single-atom catalysts derived from strong metal-support interaction for
selective hydrogenation of acetylene-
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Abstract: Selective hydrogenation of acetylene in excess ethylene is an important reaction in both fundamental study and practical application. Pd-based catalysts with high intrinsic activity are commonly employed, but usually suffer from low selectivity. Pd single-atom catalysts (SACs) usually exhibit outstanding ethylene selectivity due to the weak π-bonding ethylene adsorption. However, the preparation of high-loading and stable Pd SACs is still confronted with a great challenge. In this work, we report a simple strategy to fabricate Pd SACs by means of reducing conventional supported Pd catalysts at suitable temperatures to selectively encapsulate the co-existed Pd nanoparticles (NPs)/clusters. This is based on our new finding that single atoms only manifest strong metal-support interaction (SMSI) at higher reduction temperature than that of NPs/clusters. The derived Pd SACs (Pd1/CeO2 and Pd1/α-Fe2O3) were applied to acetylene selective hydrogenation, exhibiting much improved ethylene selectivity and high stability. This work offers a promising way to develop stable Pd SACs easily.
PubDate: 2022-05-19
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- Fabrication of LiOH-metal organic framework derived hierarchical porous
host carbon matrix composites for seasonal thermochemical energy storage-
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Abstract: By virtue of its long lifespan and outstanding storage intensity with near-zero heat loss, salt hydrate thermochemical energy storage (TES) materials provide a feasible option for the effective use of renewable energy and overcoming its unsynchronized supply and demand. Here, an activated porous carbon originating from the zeolite imidazolate framework (ZHCM) is fabricated and served as the carbon matrix for the LiOH TES material. The as-synthesized Li/ZHCM2-40 not only has excellent storage intensity (maximum 2414.2 kJ·kg−1) with low charging temperature, but also shows great hydration properties stemming from the ultrahigh surface area and hierarchical porous structure of ZHCM2. Besides, this composite material exhibits superior thermal conductivity, while its storage intensity is only attenuated by 10.2% after 15 times of consecutive charge—discharge process, revealing its outstanding cycle stability. And the numerical simulation results also demonstrate its superior heat transfer performance. The developed LiOH TES composite may afford a new avenue for efficient low-grade thermochemical energy storage and liberate the possibility of further exploration of metal organic frameworks derived porous carbon matrix in the future.
PubDate: 2022-05-19
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- Function toggle of tumor microenvironment responsive nanoagent for highly
efficient free radical stress enhanced chemodynamic therapy-
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Abstract: In contrast to reactive oxygen species (ROS), the generation of oxygen-irrelevant free radicals is oxygen- and H2O2-independent in cell, which can offer novel opportunities to maximum the chemodynamic therapy (CDT) efficacy. Herein, an H2O2-independent “functional reversion” strategy based on tumor microenvironment (TME)-toggled C-free radical generation for CDT is developed by confining astaxanthin (ATX) on the NiFe-layered double hydroxide (LDH) nanosheets (denoted as ATX/LDH). The unique ATX/LDH can demonstrate outstanding TME-responsive C-free radical generation performance by proton coupled electron transfer (PCET), owing to the specific ATX activation by unsaturated Fe sites on the LDH nanosheets formed under TME. Significantly, the Brönsted base sites of LDH hydroxide layers can promote the generation of neutral ATX C-free radicals by capturing the protons generated in the ATX activation process. Conversely, ATX/LDH maintain antioxidant performance to prevent normal tissue cancerization due to the synergy of LDH nanosheets and antioxidative ATX. In addition, C-free radical can compromise the antioxidant defense in cells to the maximum extent, compared with ROS. The free radicals burst under TME can significantly elevate free radical stress and induce cancer cell apoptosis. This strategy can realize TME-toggled C free radical generation and perform free radical stress enhanced CDT.
PubDate: 2022-05-19
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- Propolis inspired sunscreens for efficient UV-protection and skin barrier
maintenance-
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Abstract: The direct use of naturally occurring, small molecular ingredients in bioinspired sunscreens has raised several concerns due to the instability, photocytotoxicity, and potential blood toxicity of those ingredients. In this work, we have employed natural ultraviolet (UV)-blocking molecule caffeic acid phenethyl ester (CAPE) from propolis to prepare poly(CAPE) nanoparticles (NPs) as the main bioactive ingredient to fabricate propolis-inspired hydrogel sunscreens. Compared with small molecular CAPE, poly(CAPE) NPs exhibited better dispersion and stability in water, as well as lower physiological toxicity and skin permeability. And the resulting composite hydrogels demonstrated promising properties including water-resistant whereas can be easily erased by warm water as well as safety when interacting with skin. More importantly, the hydrogel sunscreens showed excellent UV protection properties both in vitro and in vivo, and the positive effects in maintaining skin barrier functions. This work provides new strategies towards the facile construction of nature-inspired robust sunscreens in the future.
PubDate: 2022-05-19
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- Erratum to: In situ construction of thiol-silver interface for selectively
electrocatalytic CO2 reduction-
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Abstract: One funding number in the Acknowledgements section was unfortunately mistakenly used. This error did not affect any of the conclusions from the published paper.
PubDate: 2022-05-18
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- Capillary grip-induced stick-slip motion
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Abstract: We present capillary grip-induced stick-slip motion, a nanoscale tribological effect, where the role of a nanoscale confined water meniscus formed between a buckled sharp tip and a glass or mica surface is addressed by shear dynamic force measurement. We obtained the effective elasticity, viscosity, conservative (elastic) and non-conservative (viscous) forces, energy dissipation, and lateral force using small oscillation, amplitude-modulation, and shear-mode quartz tuning fork-atomic force microscopy (QTF-AFM). We distinguished the conservative and non-conservative forces by investigating the dependence of normal load and relative humidity, slip length, and stick-slip frequency. We found that the confined nanoscale water enhances the lateral forces via capillary grip-induced stick-slip on a rough surface, resulting in an increase of static lateral force (3-fold for both substrates) and kinetic lateral force (6-fold for glass, 3-fold for mica). This work provides quantitative and systematic understanding of nanoscale tribology properties in humid ambient conditions and is thus useful for control of friction as well as characterization of tribology in nanomaterials and nanodevices.
PubDate: 2022-05-18
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- Heterojunction between bimetallic metal-organic framework and TiO2:
Band-structure engineering for effective photoelectrochemical water
splitting-
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Abstract: Bimetallic Fe/Ni-based metal-organic frameworks (MOFs) with different Fe/Ni ratios were coated on TiO2 nanorods (NRs), and the performances of the heterojunction photoanodes in photoelectrochemical water splitting were investigated. The bandgaps and band positions of the MOFs could be modulated by changing the ratio of the Fe and Ni components. An ideal band alignment was achieved between the TiO2 NRs and bimetallic MOFs with an optimum ratio of [Fe]/[Ni] = 0.25/0.75, which allowed efficient light absorption and charge separation. The coating of NH2−MIL(Fe)−88 layer on the TiO2 NRs decreased the photocurrent density by 33%. In comparison, TiO2/NH2−MIL(Ni)−88 showed a modest improvement in photocurrent density (0.85 mA·cm−2 at 1.23 V vs. a reversible hydrogen electrode (RHE)). When bimetallic NH2−MIL(Fe0.25Ni0.75)−88 was coated on the TiO2 NRs, the photocurrent density reached 1.56 mA·cm−2, which was an efficiency enhancement of 3.2 times. The mechanism underlying high photoelectrochemical performance was investigated.
PubDate: 2022-05-17
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- Efficient oxygen electrocatalysts with highly-exposed Co-N4 active sites
on N-doped graphene-like hierarchically porous carbon nanosheets enhancing
the performance of rechargeable Zn-air batteries-
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Abstract: Designing bifunctional oxygen electrocatalysts with high activity, lasting stability, and low-cost for rechargeable zinc-air batteries (RZABs) is a tough challenge. Herein, an advanced electrocatalyst is prepared by anchoring atomically dispersed Co atoms on N-doped graphene-like hierarchically porous carbon nanosheets (SA-Co-N4-GCs) and thereby forming Co-N4-C architecture. Its unique structure with excellent conductivity, large surface area, and three dimensional (3D) interconnected hierarchically porous architecture exposes not only more Co-N4 active sites to accelerate the kinetics of both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), but also provides an efficient charge/mass transport environment to reduce diffusion barrier. Consequently, SA-Co-N4-GCs exhibits excellent ORR/OER bifunctional activities and durability, surpassing noble-metal catalysts. Liquid RZABs using SA-Co-N4-GCs cathodes display a high open-circuit voltage of 1.51 V, a remarkable power density of 149.3 mW·cm−2, as well as excellent stability and rechargeability with faint increase in polarization even at a large depth of charge—discharge cycle with 16 h per cycle over an entire 600 h long-term test. Moreover, flexible quasi-solid-state RZABs with SA-Co-N4-GCs cathodes also deliver a considerable power density of 124.5 mW·cm−2, which is even higher than that of liquid batteries using noble-metal catalysts. This work has thrown new insight into development of high-performance and low-cost electrocatalysts for energy conversion and storage.
PubDate: 2022-05-17
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- Bacteria-assisted delivery and oxygen production of nano-enzyme for potent
radioimmunotherapy of cancer-
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Abstract: Tumor-targeting attenuated Salmonella could induce certain antitumor therapeutic effect through its proliferation characteristic and the consequent activated immune response, while host defense cells represented by neutrophils would trap and eliminate these invading bacteria via producing excess hydrogen peroxide (H2O2)-including reactive oxygen species in the bacteria-infected tumor, thereby impairing the efficacy of the bacteria treatment of tumor. Herein, we attempt to combine bacteria treatment and oxygen-dependent radioimmunotherapy of tumor through injection of neutrophil-targeted nano-catalase into the bacteria-treated mice for perfect tumor treatment outcome. Denatured albumin is used to coat catalase and deliver it to the neutrophils infiltrated in bacteria-infected tumor tissue. Taking advantage of the generating H2O2 by neutrophils, easily-diffused oxygen is produced and spread the whole tumor under the catalysis of nano-enzyme, leading to enhanced radiotherapy of hypoxic tumor cells. Moreover, the optimized tumor microenvironment, synergistically caused by potent immune-stimulation of bacteria, generating oxygen and tumor radiotherapy, would boost the antitumor immunity. This novel combination therapy strategy holds great promise to provide new ideas for future clinical cancer treatment.
PubDate: 2022-05-17
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- Erratum to: Exosome-mimicking nanovesicles derived from
efficacy-potentiated stem cell membrane and secretome for regeneration of
injured tissue-
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PubDate: 2022-05-16
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