A photothermal bacterium (PTB) is reported for tumor‐targeted photothermal therapy (PTT) by using facultative anaerobic bacterium Shewanella oneidensis MR‐1 (S. oneidensis MR‐1) to biomineralize ...palladium nanoparticles (Pd NPs) on its surface without affecting bacterial activity. It is found that PTB possesses superior photothermal property in near infrared (NIR) regions, as well as preferential tumor‐targeting capacity. Zeolitic imidazole frameworks‐90 (ZIF‐90) encapsulating photosensitizer methylene blue (MB) are hybridized on the surface of living PTB to further enhance PTT efficacy. MB‐encapsulated ZIF‐90 (ZIF‐90/MB) can selectively release MB at mitochondria and cause mitochondrial dysfunction by producing singlet oxygen (1O2) under light illumination. Mitochondrial dysfunction further contributes to adenosine triphosphate (ATP) synthesis inhibition and heat shock proteins (HSPs) down‐regulated expression. The PTB‐based therapeutic platform of PTB@ZIF‐90/MB demonstrated here will find great potential to overcome the challenges of tumor targeting and tumor heat tolerance in PTT.
A bacteria‐based photothermal therapeutic platform comprising PTB@ZIF‐90/MB is developed, which reveals great potential to augment photothermal therapy efficacy by tackling the challenges of tumor targeting and heat resistance.
We show that a suitable combination of geometric frustration, ferromagnetism, and spin-orbit interactions can give rise to nearly flatbands with a large band gap and nonzero Chern number. Partial ...filling of the flatband can give rise to fractional quantum Hall states at high temperatures (maybe even room temperature). While the identification of material candidates with suitable parameters remains open, our work indicates intriguing directions for exploration and synthesis.
Cholesteric liquid crystals (CLCs) exhibit selective reflection that can be tuned owing to the dynamic control of inherent self‐organized helical superstructures. Although phototunable reflection is ...reported, these systems hitherto suffer from a limitation in that the tuning range is restricted to one narrow period and the optically addressed images have to sacrifice one color in the visible spectrum to serve as the background, resulting from the insufficient variation in helical twisting power of existing photoresponsive chiral switches that are all bistable. Here, delicate patterns of three primary red, green, and blue (RGB) colors with a black background are presented, which is realized based on piecewise reflection tuning of the CLC induced by a newly designed photoresponsive tristable chiral switch. Three stable configurations of the chiral switch endow the CLC with two continuous and adjacent tuning periods of the reflection, covering not only entire visible spectrum, but also one more wide period within near‐infrared region. Therefore, the concept of piecewise tuning in CLC system demonstrates a new strategy for phototunable RGB and black reflective display.
A photoresponsive tristable chiral switch is constructed by incorporating two different azobenzenes into one chiral structure. Three stable configurations of the chiral switch endow the cholesteric liquid crystals with two tuning periods of the reflection, including the period in the visible spectrum and one more period within the near‐infrared region, which provides piecewise phototuning of self‐organized helical superstructures.
The concept of green chemistry is promoted by more fields. Therefore, it is necessary for the preparation of organic film under the gentle polymerization condition. In this article, the traditional ...strong acid polymerization electrolyte is replaced by a citric acid‐disodium hydrogen phosphate buffer system (pH 5.6). On the one hand, it reduces the negative effects of strong acid, and on the other hand, it avoids the damage of the metal substrate during the polymerization process. In addition, with o‐phenylenediamine (oPD) as the monomer, poly(oPD) (PoPD) films were successfully prepared by cyclic voltammetry under this system. The effects of concentration, temperature, and immersion time were investigated in 3.5% NaCl solution. It is found that temperature has a negative effect on the corrosion resistance of the coating. But when the temperature rises to 333 K, the resistance of the PoPD film is still five times higher than that of bare steel. The immersion test showed that when the film was immersed for 21.5 h, the impedance of the PoPD film was an order of magnitude larger than that of the bare steel that was impregnated at the same time. This research can provide new ideas for organic film in daily industrial production.
Witnessed by the rapid increase of power conversion efficiency to 25.5%, organic–inorganic hybrid perovskite solar cells (PSCs) are becoming promising candidates of next‐generation photovoltaics. ...However, PSCs can be unstable under the influence of light and bias. Especially, grain boundaries (GBs) are vulnerable to attack by light and bias in perovskite films, leading to degradation of photovoltaic properties of PSCs. Herein, photocurrent atomic force microscopy and Kelvin probe force microscopy are employed to systematically investigate the bias‐dependent charge transport behaviors and stability of (FAPbI3)0.85(MAPbBr3)0.15 perovskite under working condition. Bias‐dependent morphology and photocurrent images show irreversible decomposition of the perovskite at a bias of 0.1 V or below, which is accelerated by light illumination, leading to formation of an interfacial layer that restricts carrier transport. Meanwhile, GBs appear to enhance carrier transport at larger bias, but serve as breakthrough sites for perovskite decomposition at smaller bias. Introducing excess methylammonium iodide promotes decomposition, while potassium iodide passivation greatly relieves the decomposition. These results support the ion migration mechanism of decomposition through interfaces and GBs. This work provides a deeper understanding of bias‐induced degradation of PSCs as well as bias‐dependent double‐edged roles of GBs, and forms valuable guidance for appropriate operation of PSCs.
Bias‐dependent stability of (FAPbI3)0.85(MAPbBr3)0.15 perovskite and double‐edged roles of grain boundaries in carrier transport and degradation of solar cells under working condition are systematically investigated. Photocurrent atomic force microscopy results show that grain boundaries enhance carrier transport at larger bias, but serve as breakthrough sites at smaller bias of 0.1 V or below when irreversible decomposition of perovskite occurs.
Abstract
Metal-organic layers with ordered structure and molecular tunability are of great potential as heterogeneous catalysts due to their readily accessible active sites. Herein, we demonstrate a ...facile template strategy to prepare metal-organic layers with a uniform thickness of three metal coordination layers (ca. 1.5 nm) with graphene oxide as both template and electron mediator. The resulting hybrid catalyst exhibits an excellent performance for CO
2
photoreduction with a total CO yield of 3133 mmol g
–1
MOL
(CO selectivity of 95%), ca. 34 times higher than that of bulky Co-based metal-organic framework. Systematic studies reveal that well-exposed active sites in metal-organic layers, and facile electron transfer between heterogeneous and homogeneous components mediated by graphene oxide, greatly contribute to its high activity. This work highlights a facile way for constructing ultrathin metal-organic layers and demonstrates charge transfer pathway between conductive template and catalyst for boosting photocatalysis.
The reduction of carbon dioxide (CO2) has been considered as an approach to mitigate global warming and to provide renewable carbon‐based fuels. Rational design of efficient, selective, and ...inexpensive catalysts with low overpotentials is urgently desired. In this study, four cobalt(II) tripodal complexes are tested as catalysts for CO2 reduction to CO in a MeCN/H2O (4:1 v/v) solution. The replacement of pyridyl groups in the ligands with less basic quinolinyl groups greatly reduces the required overpotential for CO2‐to‐CO conversion down to 200–380 mV. Benefitting from the low overpotentials, a photocatalyst system for CO2‐to‐CO conversion is successfully constructed, with an maximum turnover number (TON) of 10 650±750, a turnover frequency (TOF) of 1150±80 h−1, and almost 100 % selectivity to CO. These outstanding catalytic performances are further elucidated by DFT calculations.
Electric/light orchestration: Four cobalt complexes with tripodal ligands are utilized as high‐performance molecular electro‐ and photocatalysts for the reduction of CO2 to CO in a water‐containing system. By the introduction of less basic aromatic nitrogen donors in the tripodal ligands, the overpotentials can be reduced down to record low values of 200–380 mV, leading to high efficiency and selectivity for photocatalytic reduction of CO2 to CO.
Nerve conduits are used to reconnect broken nerve bundles and provide protection to facilitate nerve regeneration. However, the low degradation rate and regeneration rate, as well as the requirement ...for secondary surgery are some of the most criticized drawbacks of existing nerve conduits. With high processing flexibility from the photo‐curability, poly (glycerol sebacate) acrylate (PGSA) is a promising material with tunable mechanical properties and biocompatibility for the development of medical devices. Here, polyvinylpyrrolidone (PVP), silver nanoparticles (AgNPs), and graphene are embedded in biodegradable PGSA matrix. The polymer composites are then assessed for their electrical conductivity, biodegradability, three‐dimensional‐printability (3D‐printability), and promotion of cell proliferation. Through the four‐probe technique, it is shown that the PGSA composites are identified as highly conductive in swollen state. Furthermore, biodegradability is evaluated through enzymatic degradation and facilitated hydrolysis. Cell proliferation and guidance are significantly promoted by three‐dimensional‐printed microstructures and electrical stimulation on PGSA composites, especially on PGSA‐PVP. Hence, microstructured nerve conduits are 3D‐printed with PGSA‐PVP. Guided cell growth and promoted proliferation are subsequently demonstrated by Schwann cell culture combined with electrical stimulation. Consequently, 3D‐printed nerve conduits fabricated with PGSA composites hold great potential in nerve tissue regeneration through electrical stimulation.
Biodegradable, conductive poly (glycerol sebacte) acrylate (PGSA) composites are developed for nerve regeneration using electrical stimulation. The electrical conductivity, biocompatibility, and biodegradability of composites embedded with polyvinylpyrrolidone (PVP), silver nanoparticles (AgNPs), and graphene are investigated. PGSA composites microgrooved scaffolds are fabricated through digital light processing additive manufacturing (DLP‐AM) system. The proposed scaffold is proven to promote neural cell proliferation.
ORP5 and ORP8, members of the oxysterol-binding protein (OSBP)-related proteins (ORP) family, are endoplasmic reticulum membrane proteins implicated in lipid trafficking. ORP5 and ORP8 are reported ...to localize to endoplasmic reticulum-plasma membrane junctions via binding to phosphatidylinositol-4-phosphate (PtdIns(4)P), and act as a PtdIns(4)P/phosphatidylserine counter exchanger between the endoplasmic reticulum and plasma membrane. Here we provide evidence that the pleckstrin homology domain of ORP5/8 via PtdIns(4,5)P
, and not PtdIns(4)P binding mediates the recruitment of ORP5/8 to endoplasmic reticulum-plasma membrane contact sites. The OSBP-related domain of ORP8 can extract and transport multiple phosphoinositides in vitro, and knocking down both ORP5 and ORP8 in cells increases the plasma membrane level of PtdIns(4,5)P
with little effect on PtdIns(4)P. Overall, our data show, for the first time, that phosphoinositides other than PtdIns(4)P can also serve as co-exchangers for the transport of cargo lipids by ORPs.ORP5/8 are endoplasmic reticulum (ER) membrane proteins implicated in lipid trafficking that localize to ER-plasma membrane (PM) contacts and maintain membrane homeostasis. Here the authors show that PtdIns(4,5)P
plays a critical role in the targeting and function of ORP5/8 at the PM.
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