Electrically driven molecular light emitters are considered to be one of the promising candidates as single-photon sources. However, it is yet to be demonstrated that electrically driven ...single-photon emission can indeed be generated from an isolated single molecule notwithstanding fluorescence quenching and technical challenges. Here, we report such electrically driven single-photon emission from a well-defined single molecule located inside a precisely controlled nanocavity in a scanning tunneling microscope. The effective quenching suppression and nanocavity plasmonic enhancement allow us to achieve intense and stable single-molecule electroluminescence. Second-order photon correlation measurements reveal an evident photon antibunching dip with the single-photon purity down to g
(0) = 0.09, unambiguously confirming the single-photon emission nature of the single-molecule electroluminescence. Furthermore, we demonstrate an ultrahigh-density array of identical single-photon emitters.Molecular emitters offer a promising solution for single-photon generation. Here, by exploiting electronic decoupling by an ultrathin dielectric spacer and emission enhancement by a resonant plasmonic nanocavity, the authors demonstrate electrically driven single-photon emission from a single molecule.
Exosomes contain cell-specific collections of bioactive materials including proteins, lipids, and RNAs that are transported to recipient cells to exert their impacts. MicroRNAs (miRNAs) can function ...as tumor suppressor or oncogenic genes and miR-21 is one of the most frequently up-regulated miRNAs in solid tumors including colon cancer. The aim of this study was to investigate the role of miR-21, secreted from exosomes, in proliferation and invasion of colon cancer, along with the mechanistic details. We used a variety of biochemical techniques including ultracentrifugation-based exosome purification, electron transmission microscopy, western blot and RT-qPCR to detect the expression levels of miR-21 in exosomes purified from culture media of human colonic adenocarcinoma cell lines. We then performed functional and mechanistic studies using three colon cancer cell lines HT29, T84 and LS174 as well as the normal colon epithelial cells CRL1831. miR-21 target PDCD4 was investigated for its role in mediating miR-21 effects. Expression of miR-21 was significantly up-regulated in exosomes of colon cancer cells, compared to the normal human colon epithelial cells. Treatment of colon cancer cells with isolated exosomes or miR-21 led to an increased expression of genes involved in cell proliferation, invasion and extracellular matrix formation. miR-21 targets PDCD4, TPM1 and PTEN were down-regulated by exosomes and silencing of PDCD4 mimicked miR-21 functional effects, even the induced resistance against 5-FU. Our study suggests that targeted inhibition of exosomes, particularly those carrying miR-21, may represent a novel approach for treatment of colorectal cancer.
The coherent interaction between quantum emitters and photonic modes in cavities underlies many of the current strategies aiming at generating and controlling photonic quantum states. A plasmonic ...nanocavity provides a powerful solution for reducing the effective mode volumes down to nanometre scale, but spatial control at the atomic scale of the coupling with a single molecular emitter is challenging. Here we demonstrate sub-nanometre spatial control over the coherent coupling between a single molecule and a plasmonic nanocavity in close proximity by monitoring the evolution of Fano lineshapes and photonic Lamb shifts in tunnelling electron-induced luminescence spectra. The evolution of the Fano dips allows the determination of the effective interaction distance of ∼1 nm, coupling strengths reaching ∼15 meV and a giant self-interaction induced photonic Lamb shift of up to ∼3 meV. These results open new pathways to control quantum interference and field-matter interaction at the nanoscale.
Conjugated polymers with high thermoelectric performance enable the fabrication of low‐cost, large‐area, low‐toxicity, and highly flexible thermoelectric devices. However, compared to their p‐type ...counterparts, n‐type polymer thermoelectric materials show much lower performance, which is largely due to inefficient doping and a much lower conductivity. Herein, it is reported that the development of a donor–acceptor (D–A) polymer with enhanced n‐doping efficiency through donor engineering of the polymer backbone. Both a high n‐type electrical conductivity of 1.30 S cm−1 and an excellent power factor (PF) of 4.65 µW mK−2 are obtained, which are the highest reported values among D–A polymers. The results of multiple characterization techniques indicate that electron‐withdrawing modification of the donor units enhances the electron affinity of the polymer and changes the polymer packing orientation, leading to substantially improved miscibility and n‐doping efficiency. Unlike previous studies in which improving the polymer‐dopant miscibility typically resulted in lower mobilities, the strategy maintains the mobility of the polymer. All these factors lead to prominent enhancement of three orders magnitude in both the electrical conductivity and the PF compared to those of the non‐engineered polymer. The results demonstrate that proper donor engineering can enhance the n‐doping efficiency, electrical conductivity, and thermoelectric performance of D–A copolymers.
1000‐fold enhancements in n‐type electrical conductivity and power factor of a donor–acceptor copolymer are obtained by donor engineering. Donor engineering enhances electron affinity and n‐doping efficiency, prevents phase separation, lowers hopping barrier and keeps mobility unaffected. A record electrical conductivity of 1.30 S cm−1 and a power factor of 4.65 μW mK−2 are achieved in this work.
Cadmium (Cd) has been confirmed as an environmental contaminant, which potential threats health impacts to humans and animals. Selenium (Se) as a beneficial element that alleviates the negative ...effects of Cd toxicity. Se mainly exists in two forms in food nutrients including organic Se usually as (Se-enriched yeast (SeY)) and inorganic Se (sodium selenite (SSe)). Nanoparticle of Se (Nano-Se), a new form Se, which is synthesized by the bioreduction of Se species, which attracted significant attention recently. However, compared the superiority alleviation effects of Nano-Se, SeY or SSe on Cd-induced toxicity and related mechanisms are still poorly understood. The purpose of this study was to compare the superiority antagonism effects of Nano-Se, SeY and SSe on Cd-induced inflammation response via NF-kB/IκB pathway in the heart. The present study demonstrated that exposed to Cd obviously increased the accumulation of Cd, disruption of ion homeostasis and depressed the ratios of K+/Na+ and Mg2+/Ca2+ via ion chromatography mass spectrometry (ICP-MS) detecting the heart specimens. In the results of histological and ultrastructure observation, typical inflammatory infiltrate characteristics and mitochondria and nuclear structure alterations in the hearts of Cd group were confirmed. Cd treatment enhanced the inducible nitric oxide synthase (iNOS) activities and NOS isoforms expression via NF-kB/IκB pathway to promote inflammation response. However, the combined treatment of Cd-exposed animals with Nano-Se was more effective than SeY and SSe in reversing Cd-induced histopathological changes and iNOS activities increased, reducing Cd accumulation and antagonizing Cd-triggered inflammation response via NF-kB/IκB pathway in chicken hearts. Overall, Se applications, especially Nano-Se, can be most efficiently used for relieving cardiotoxicity by exposed to Cd compared to other Se compound.
The present study performs a novel insight on the protective comparative of different Se sources (Nano-Se, SeY, SSe) to Cd-induced cardiotoxicity via NF-kB/IκB pathway. Display omitted
•Nano-Se obviously mitigated Cd-induced cardiac injury.•Nano-Se relieved disruption of element balance and Cd accumulation.•Nano-Se attenuated Cd-induced inflammation response via NF-kB/IκB signaling pathway.•Nano-Se was superior to SeY and SSe in alleviating Cd caused cardiotoxicity.
Vibronic coupling is a central issue in molecular spectroscopy. Here we investigate vibronic coupling within a single pentacene molecule in real space by imaging the spatial distribution of ...single-molecule electroluminescence via highly localized excitation of tunneling electrons in a controlled plasmonic junction. The observed two-spot orientation for certain vibronic-state imaging is found to be evidently different from the purely electronic 0-0 transition, rotated by 90°, which reflects the change in the transition dipole orientation from along the molecular short axis to the long axis. Such a change reveals the occurrence of strong vibronic coupling associated with a large Herzberg-Teller contribution, going beyond the conventional Franck-Condon picture. The emergence of large vibration-induced transition charges oscillating along the long axis is found to originate from the strong dynamic perturbation of the anti-symmetric vibration on those carbon atoms with large transition density populations during electronic transitions.
•1,3-PD production was summarized in the view of bioprocess and bioengineering.•Microbial consortium has potential application for 1,3-PD production.•Salting-out and sugaring-out extraction have ...advantages for industrial production.•Microbial electrosynthesis is a novel technology for 1,3-PD production.•It represent challenges for efficient conversion of biomass hydrolysate to 1,3-PD.
1,3-Propanediol, a monomer for synthesis of polytrimethylene terephthalate, polyethers, polyurethanes, and heterocyclic compounds, has attracted worldwide attention. It can be produced from renewable resources using microorganisms, which focus mainly on the ecologically friendly process, industrial safety and sustainable development. This review summarized and commented in the view of bioprocess and bioengineering, especially on bioconversion of glycerol into 1,3-PD since 2010. Various strategies for microbial production of 1,3-PD from glycerol including strains screening and improvement, two-step and multi-stage fermentation, sole and co-substrate fermentation, co-culture, and microbial consortium were reviewed and compared. Besides experiments, theoretical analyses, such as fermentation kinetics, stability and robustness analysis, metabolic and system engineering analysis were also highlighted. The present strategies of the downstream processing of 1,3-PD were compared according to their advantages and drawbacks. Meanwhile, the novel technology of microbial electrosynthesis for biochemicals was well introduced and discussed. Finally, The future prospects and challenges of 1,3-propanediol from biotechnology were discussed for its industrial production.
As the world marches into the era of the Internet of Things (IoT), the practice of human health care is on the cusp of a revolution, driven by an unprecedented level of personalization enabled by a ...variety of wearable bioelectronics. A sustainable and wearable energy solution is highly desired , but challenges still remain in its development. Here, we report a high-performance wearable electricity generation approach by manipulating the relative permittivity of a triboelectric nanogenerator (TENG). A compatible active carbon (AC)-doped polyvinylidene fluoride (AC@PVDF) composite film was invented with high relative permittivity and a specific surface area for wearable biomechanical energy harvesting. Compared with the pure PVDF, the 0.8% AC@PVDF film-based TENG obtained an enhancement in voltage, current, and power by 2.5, 3.5, and 9.8 times, respectively. This work reports a stable, cost-effective, and scalable approach to improve the performance of the triboelectric nanogenerator for wearable biomechanical energy harvesting, thus rendering a sustainable and pervasive energy solution for on-body electronics.
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