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1.
The inhibition of amyloid‐β (Aβ) aggregation by photo‐oxygenation has become an effective way of treating Alzheimer's disease (AD). New near‐infrared (NIR) activated treatment agents, which not only possess high photo‐oxygenation efficiency, but also show low biotoxicity, are urgently needed. Herein, for the first time, it is demonstrated that NIR activated black phosphorus (BP) could serve as an effective nontoxic photo‐oxidant for amyloid?β peptide in vitro and in vivo. The nanoplatform BP@BTA (BTA: one of thioflavin‐T derivatives) possesses high affinity to the Aβ peptide due to specific amyloid selectivity of BTA. Importantly, under NIR light, BP@BTA can significantly generate a high quantum yield of singlet oxygen (1O2) to oxygenate Aβ, thereby resulting in inhibiting the aggregation and attenuating Aβ‐induced cytotoxicity. In addition, BP could finally degrade into nontoxic phosphate, which guarantees the biosafety. Using transgenic Caenorhabditis elegans CL2006 as AD model, the results demonstrate that the 1O2‐generation system could dramatically promote life‐span extension of CL2006 strain by decreasing the neurotoxicity of Aβ.  相似文献   

2.
The past three decades have witnessed notable advances in establishing photosensitizer–antibody photo‐immunoconjugates for photo‐immunotherapy and imaging of tumors. Photo‐immunotherapy minimizes damage to surrounding healthy tissue when using a cancer‐selective photo‐immunoconjugate, but requires a threshold intracellular photosensitizer concentration to be effective. Delivery of immunoconjugates to the target cells is often hindered by I) the low photosensitizer‐to‐antibody ratio of photo‐immunoconjugates and II) the limited amount of target molecule presented on the cell surface. Here, a nanoengineering approach is introduced to overcome these obstacles and improve the effectiveness of photo‐immunotherapy and imaging. Click chemistry coupling of benzoporphyrin derivative (BPD)–Cetuximab photo‐immunoconjugates onto FKR560 dye‐containing poly(lactic‐co‐glycolic acid) nanoparticles markedly enhances intracellular photo‐immunoconjugate accumulation and potentiates light‐activated photo‐immunotoxicity in ovarian cancer and glioblastoma. It is further demonstrated that co‐delivery and light activation of BPD and FKR560 allow longitudinal fluorescence tracking of photoimmunoconjugate and nanoparticle in cells. Using xenograft mouse models of epithelial ovarian cancer, intravenous injection of photo‐immunoconjugated nanoparticles doubles intratumoral accumulation of photo‐immunoconjugates, resulting in an enhanced photoimmunotherapy‐mediated tumor volume reduction, compared to “standard” immunoconjugates. This generalizable “carrier effect” phenomenon is attributed to the successful incorporation of photo‐immunoconjugates onto a nanoplatform, which modulates immunoconjugate delivery and improves treatment outcomes.  相似文献   

3.
Organic–inorganic halide perovskites (OIHPs) have demonstrated outstanding energy conversion efficiency in solar cells and light‐emitting devices. In spite of intensive developments in both materials and devices, electronic traps and defects that significantly affect their device properties remain under‐investigated. Particularly, it remains challenging to identify and to resolve traps individually at the nanoscopic scale. Here, photo‐active traps (PATs) are mapped over OIHP nanocrystal morphology of different crystallinity by means of correlative optical differential super‐resolution localization microscopy (Δ‐SRLM) and electron microscopy. Stochastic and monolithic photoluminescence intermittency due to individual PATs is observed on monocrystalline and polycrystalline OIHP nanocrystals. Δ‐SRLM reveals a heterogeneous PAT distribution across nanocrystals and determines the PAT density to be 1.3 × 1014 and 8 × 1013 cm?3 for polycrystalline and for monocrystalline nanocrystals, respectively. The higher PAT density in polycrystalline nanocrystals is likely related to an increased defect density. Moreover, monocrystalline nanocrystals that are prepared in an oxygen‐ and moisture‐free environment show a similar PAT density as that prepared at ambient conditions, excluding oxygen or moisture as chief causes of PATs. Hence, it is concluded that the PATs come from inherent structural defects in the material, which suggests that the PAT density can be reduced by improving crystalline quality of the material.  相似文献   

4.
Polymeric materials used in spacecraft require to be protected with an atomic oxygen (AO)‐resistant layer because AO can degrade these polymers when spacecraft serves in low earth orbit (LEO) environment. However, mechanical damage on AO‐resistant coatings can expose the underlying polymers to AO erosion, shortening their service life. In this study, the fabrication of durable AO‐resistant coatings that are capable of autonomously healing mechanical damage under LEO environment is presented. The self‐healing AO‐resistant coatings are comprised of 2‐ureido‐4[1H]‐pyrimidinone (UPy)‐functionalized polyhedral oligomeric silsesquioxane (POSS) (denoted as UPy‐POSS) that forms hydrogen‐bonded three‐dimensional supramolecular polymers. The UPy‐POSS supramolecular polymers can be conveniently deposited on polyimides by a hot pressing process. The UPy‐POSS polymeric coatings are mechanically robust, thermally stable, and transparent and have a strong adhesion toward polyimides to endure repeated bending/unbending treatments and thermal cycling. The UPy‐POSS polymeric coatings exhibit excellent AO attack resistance because of the formation of epidermal SiO2 layer after AO exposure. Due to the reversibility of the quadruple hydrogen bonds between UPy motifs, the UPy‐POSS polymeric coatings can rapidly heal mechanical damage such as cracks at 80 °C or under LEO environment to restore their original AO‐resistant function.  相似文献   

5.
A hexafluorophosphate ionic liquid is used as a functional monomer to prepare a metal–organic framework (Zn‐MOF). Zn‐MOF is used as a template for MoS2 nanosheets synthesis and further carbonized to yield light‐responsive ZnS/C/MoS2 nanocomposites. Zn‐MOF, carbonized‐Zn‐MOF, and ZnS/C/MoS2 nanocomposites are characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, X‐ray diffraction pattern, scanning electron microscopy (SEM), element mapping, Raman spectroscopy, X‐ray photoelectron spectroscopy, fluorescence, and nitrogen‐adsorption analysis. Carcinoembryonic antigen (CEA) is selected as a model to construct an immunosensing platform to evaluate the photo‐electrochemical (PEC) performances of ZnS/C/MoS2 nanocomposites. A sandwich‐type PEC immunosensor is fabricated by immobilizing CEA antibody (Ab1) onto the ZnS/C/MoS2/GCE surface, subsequently binding CEA and the alkaline phosphatase‐gold nanoparticle labeled CEA antibody (ALP‐Au‐Ab2). The catalytic conversion of vitamin C magnesium phosphate produces ascorbic acid (AA). Upon being illuminated, AA can react with photogenerated holes from ZnS/C/MoS2 nanocomposites to generate a photocurrent for quantitative assay. Under optimized experimental conditions, the PEC immunosensor exhibits excellent analytical characteristics with a linear range from 2.0 pg mL?1 to 10.0 ng mL?1 and a detection limit of 1.30 pg mL?1 (S/N = 3). The outstanding practicability of this PEC immunosensor is demonstrated by accurate assaying of CEA in clinical serum samples.  相似文献   

6.
The photo‐induced reconfigurable assembly of nanostructures via the simultaneous noncovalent and covalent polymerization of a functional ferrocene‐tyrosine (Fc‐Y) molecule is reported. The Fc‐Y monomers can directly self‐assemble into nanospheres with a smooth surface driven by noncovalent interactions. By covalent photo‐crosslinking of the Fc‐Y monomers, the nanospheres transform spontaneously into hollow vesicles composed of hierarchically ordered lamellar structures. It is worth noting that the formed nanostructures exhibit both reducing property for in situ mineralization of gold nanoparticles with tunable biocatalytic behavior, and the redox activity for superior energy storage capacity. The measured energy storage capacity is 31 mAh g−1 for the nanospheres, which is the highest value reported so far for peptide assemblages as supercapacitor. The results offer insights into the dynamic self‐assembly of highly ordered multifunctional materials with promising applications in catalysis, sensing, energy and biomedical fields.  相似文献   

7.
Transition metal chalcogenides are investigated for catalyst, intermediary agency, and particular optical properties because of their distinguished electron‐vacancy‐transfer (EVT) process toward different applications. In this work, one convenient approach for making pure‐phased FeSe nanocrystals (NCs) and doped CuFeSe nanosheets (NSs) through a wet chemistry method in mixed solvents is illustrated. The surface modification of each product is realized by using a peptide molecule glutathione (GSH), in which the thiol group (?SH) is ascribed to be the in situ reducer and bonding agency between the crystalline surface and surfactant in whole constructing processes. Due to the functional groups in biological GSH, highly aggregated NCs are rebuilt in the form of an FeSe hollow structure through amino and carboxyl cross‐linking functions through a spontaneous assembly procedure. Owing to the coupling procedure of Cu and Fe in the growth process, it generates enhanced EVT. Additionally, it shows the emission spectra of λEM‐PL = 436 nm (FeSe) and 452 nm (CuFeSe) while λEX‐PL = 356 nm, it also conveys two‐photon phenomenon while λEX‐PL = 720 nm. Moreover, it also shows strong off‐resonant luminescence due to two‐photon absorption, which should be valuable for biological applications.  相似文献   

8.
Porous single crystals are promising candidates for solar fuel production owing to their long range charge diffusion length, structural coherence, and sufficient reactive sites. Here, a simple template‐free method of growing a selectively branched, 2D anatase TiO2 porous single crystalline nanostructure (PSN) on fluorine‐doped tin oxide substrate is demonstrated. An innovative ion exchange–induced pore‐forming process is designed to successfully create high porosity in the single‐crystalline nanostructure with retention of excellent charge mobility and no detriment to crystal structure. PSN TiO2 film delivers a photocurrent of 1.02 mA cm?2 at a very low potential of 0.4 V versus reversible hydrogen electrode (RHE) for photo‐electrochemical water splitting, closing to the theoretical value of TiO2 (1.12 mA cm?2). Moreover, the current–potential curve featuring a small potential window from 0.1 to 0.4 V versus RHE under one‐sun illumination has a near‐ideal shape predicted by the Gartner Model, revealing that the charge separation and surface reaction on the PSN TiO2 photoanode are very efficient. The photo‐electrochemical water splitting performance of the films indicates that the ion exchange–assisted synthesis strategy is effective in creating large surface area and single‐crystalline porous photoelectrodes for efficient solar energy conversion.  相似文献   

9.
Collecting and storing solar energy to hydrogen fuel through a photo‐electrochemical (PEC) cell provides a clean and renewable pathway for future energy demands. Having earth‐abundance, low biotoxicity, robustness, and an ideal n‐type band position, hematite (α‐Fe2O3), the most common natural form of iron oxide, has occupied the research hotspot for decades. Here, a close look into recent progress of hematite photoanodes for PEC water splitting is provided. Effective approaches are introduced, such as cocatalysts loading and surface passivation layer deposition, to improve the hematite surface reaction in thermodynamics and kinetics. Second, typical methods for enhancing light absorption and accelerating charge transport in hematite bulk are reviewed, concentrating upon doping and nanostructuring. Third, the back contact between hematite and substrate, which affects interface states and electron transfer, is deliberated. In addition, perspectives on the key challenges and future prospects for the development of hematite photoelectrodes for PEC water splitting are given.  相似文献   

10.
Photo‐electrochemical water splitting represents a green and environmentally friendly method for producing solar hydrogen. Semiconductor nanomaterials with a highly accessible surface area, reduced charge migration distance, and tunable optical and electronic property are regarded as promising electrode materials to carry out this solar‐to‐hydrogen process. Since most of the photo‐electrochemical reactions take place on the electrode surface or near‐surface region, rational engineering of the surface structures, physical properties, and chemical nature of photoelectrode materials could fundamentally change their performance. Here, the recent advances in surface engineering methods, including the modification of the nanomaterial surface morphology, crystal facet, defect and doping concentrations, as well as the deposition of a functional overlayer of sensitizers, plasmonic metallic structures, and protective and catalytic materials are highlighted. Each surface engineering method and how it affects the structural features and photo‐electrochemical performance of nanomaterials are reviewed and compared. Finally, the current challenges and the opportunities in the field are discussed.  相似文献   

11.
The use of abundant solar energy for regeneration and desalination of water is a promising strategy to address the challenge of a global shortage of clean water. Progress has been made to develop photothermal materials to improve the solar steam generation performance. However, the mass production rate of water is still low. Herein, by a rational combination of photo‐electro‐thermal effect on an all‐graphene hybrid architecture, solar energy can not only be absorbed fully and transferred into heat, but also converted into electric power to further heat up the graphene skeleton frame for a much enhanced generation of water vapor. As a result, the unique graphene evaporator reaches a record high water production rate of 2.01–2.61 kg m?2 h?1 under solar illumination of 1 kW m?2 even without system optimization. Several square meters of the graphene evaporators will provide a daily water supply that is enough for tens of people. The combination of photo‐electro‐thermal effect on graphene materials offers a new strategy to build a fast and scalable solar steam generation system, which makes an important step towards a solution for the scarcity of clean water.  相似文献   

12.
Tumor hypoxia significantly diminishes the efficacy of reactive oxygen species (ROS)‐based therapy, mainly because the generation of ROS is highly oxygen dependent. Recently reported hypoxia‐irrelevant radical initiators (AIBIs) exhibit promising potential for cancer therapy under different oxygen tensions. However, overexpressed glutathione (GSH) in cancer cells would potently scavenge the free radicals produced from AIBI before their arrival to the specific site and dramatically limit the therapeutic efficacy. A synergistic antitumor platform (MoS2@AIBI‐PCM nanoflowers) is constructed by incorporating polyethylene‐glycol‐functionalized molybdenum disulfide (PEG‐MoS2) nanoflowers with azo initiator and phase‐change material (PCM). Under near‐infrared laser (NIR) irradiation, the photothermal feature of PEG‐MoS2 induces the decomposition of AIBI to produce free radicals. Furthermore, PEG‐MoS2 can facilitate GSH oxidation without releasing toxic metal ions, greatly promoting tumor apoptosis and avoiding the introduction of toxic metal ions. This is the first example of the use of intelligent MoS2‐based nanoflowers as a benign GSH scavenger for enhanced cancer treatment.  相似文献   

13.
Quasi‐1D cadmium chalcogenide quantum rods (QRs) are benchmark semiconductor materials that are combined with noble metals to constitute QR heterostructures for efficient photocatalysis. However, the high toxicity of cadmium and cost of noble metals are the main obstacles to their widespread use. Herein, a facile colloidal synthetic approach is reported that leads to the spontaneous formation of cadmium‐free alloyed ZnSxSe1?x QRs from polydisperse ZnSe nanowires by alkylthiol etching. The obtained non‐noble‐metal ZnSxSe1?x QRs can not only be directly adopted as efficient photocatalysts for water oxidation, showing a striking oxygen evolution capability of 3000 µmol g?1 h?1, but also be utilized to prepare QR‐sensitized TiO2 photoanodes which present enhanced photo‐electrochemical (PEC) activity. Density functional theory (DFT) simulations reveal that alloyed ZnSxSe1?x QRs have highly active Zn sites on the (100) surface and reduced energy barrier for oxygen evolution, which in turn, are beneficial to their outstanding photocatalytic and PEC activities.  相似文献   

14.
The incidence of triple‐negative breast cancer (TNBC) is difficult to predict, and TNBC has a high mortality rate among women worldwide. In this study, a theranostics approach is developed for TNBC with ratiometric photoacoustic monitored thiol‐initiated hydrogen sulfide (H2S) therapy. The ratiometric photoacoustic (PA) probe (CY) with a thiol‐initiated H2S donor (PSD) to form a nanosystem (CY‐PSD nanoparticles) is integrated. In this theranostics approach, H2S generated from PSD is sensed by CY based on ratiometric PA signals, which simultaneously pinpoints the tumor region. Additionally, H2S is cytotoxic toward TNBC cells (MDA‐MB 231), showing a tumor inhibition rate of 63%. To further verify its pharmacological mechanism, proteomics analysis is performed on tumors treated with CY‐PSD nanoparticles. Cells are killed by the significant mitochondrial dysfunction via supressed energy supply and apoptosis initiation. Besides, the observed inhibition of oxidative stress also generates the cytotoxicity. Significant Kyoto Encyclopedia of Genes Genomes pathways related to TNBC are found to be inhibited. This H2S theranostics approach updates the current anticancer therapies which brings promise for women suffering malignant breast cancer.  相似文献   

15.
The nonaqueous lithium oxygen battery is a promising candidate as a next‐generation energy storage system because of its potentially high energy density (up to 2–3 kW kg?1), exceeding that of any other existing energy storage system for storing sustainable and clean energy to reduce greenhouse gas emissions and the consumption of nonrenewable fossil fuels. To achieve high energy density, long cycling stability, and low cost, the air electrode structure and the electrocatalysts play important roles. Here, a metal‐free, free‐standing macroporous graphene@graphitic carbon nitride (g‐C3N4) composite air cathode is first reported, in which the g‐C3N4 nanosheets can act as efficient electrocatalysts, and the macroporous graphene nanosheets can provide space for Li2O2 to deposit and also promote the electron transfer. The electrochemical results on the graphene@g‐C3N4 composite air electrode show a 0.48 V lower charging plateau and a 0.13 V higher discharging plateau than those of pure graphene air electrode, with a discharge capacity of nearly 17300 mA h g?1 (composite). Excellent cycling performance, with terminal voltage higher than 2.4 V after 105 cycles at 1000 mA h g?1 (composite) capacity, can also be achieved. Therefore, this hybrid material is a promising candidate for use as a high energy, long‐cycle‐life, and low‐cost cathode material for lithium oxygen batteries.  相似文献   

16.
Flexible Zn‐air batteries have recently emerged as one of the key energy storage systems of wearable/portable electronic devices, drawing enormous attention due to the high theoretical energy density, flat working voltage, low cost, and excellent safety. However, the majority of the previously reported flexible Zn‐air batteries encounter problems such as sluggish oxygen reaction kinetics, inferior long‐term durability, and poor flexibility induced by the rigid nature of the air cathode, all of which severely hinder their practical applications. Herein, a defect‐enriched nitrogen doped–graphene quantum dots (N‐GQDs) engineered 3D NiCo2S4 nanoarray is developed by a facile chemical sulfuration and subsequent electrophoretic deposition process. The as‐fabricated N‐GQDs/NiCo2S4 nanoarray grown on carbon cloth as a flexible air cathode exhibits superior electrocatalytic activities toward both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), outstanding cycle stability (200 h at 20 mA cm?2), and excellent mechanical flexibility (without observable decay under various bending angles). These impressive enhancements in electrocatalytic performance are mainly attributed to bifunctional active sites within the N‐GQDs/NiCo2S4 catalyst and synergistic coupling effects between N‐GQDs and NiCo2S4. Density functional theory analysis further reveals that stronger OOH* dissociation adsorption at the interface between N‐GQDs and NiCo2S4 lowers the overpotential of both ORR and OER.  相似文献   

17.
Single‐component multicolor luminescence, particularly phosphorescence materials are highly attractive both in numerous applications and in‐depth understanding the light‐emission processes, but formidable challenges still exist for preparing such materials. Herein, a very facile approach is reported to synthesize carbon dots (CDs) (named MP‐CDs) that exhibit multicolor fluorescence (FL), and more remarkably, multicolor long‐lived room temperature phosphorescence (RTP) under ambient conditions. The FL and RTP colors of the CDs powder are observed to change from blue to green and cyan to yellow, respectively, with the excitation wavelength shifting from 254 to 420 nm. Further studies demonstrate that the multicolor emissions can be attributed to the existence of multiple emitting centers in the CDs and the relatively higher reaction temperature plays a critical role for achieving RTP. Given the unique optical properties, a preliminary application of MP‐CDs in advanced anti‐counterfeiting is presented. This study not only proposes a strategy to prepare photo‐stimulated multicolor RTP materials, but also reveals great potentials of CDs in exploiting novel optical materials with unique properties.  相似文献   

18.
Recently, binary ZnCo2O4 has drawn enormous attention for lithium‐ion batteries (LIBs) as attractive anode owing to its large theoretical capacity and good environmental benignity. However, the modest electrical conductivity and serious volumetric effect/particle agglomeration over cycling hinder its extensive applications. To address the concerns, herein, a rapid laser‐irradiation methodology is firstly devised toward efficient synthesis of oxygen‐vacancy abundant nano‐ZnCo2O4/porous reduced graphene oxide (rGO) hybrids as anodes for LIBs. The synergistic contributions from nano‐dimensional ZnCo2O4 with rich oxygen vacancies and flexible rGO guarantee abundant active sites, fast electron/ion transport, and robust structural stability, and inhibit the agglomeration of nanoscale ZnCo2O4, favoring for superb electrochemical lithium‐storage performance. More encouragingly, the optimal L‐ZCO@rGO‐30 anode exhibits a large reversible capacity of ≈1053 mAh g?1 at 0.05 A g?1, excellent cycling stability (≈746 mAh g?1 at 1.0 A g?1 after 250 cycles), and preeminent rate capability (≈686 mAh g?1 at 3.2 A g?1). Further kinetic analysis corroborates that the capacitive‐controlled process dominates the involved electrochemical reactions of hybrid anodes. More significantly, this rational design holds the promise of being extended for smart fabrication of other oxygen‐vacancy abundant metal oxide/porous rGO hybrids toward advanced LIBs and beyond.  相似文献   

19.
Nano‐photocatalysts are known for their ability to degrade pollutants or perform water splitting catalyzed by light. Being the key functional ingredients of current and future products, the potential of nano‐photocatalysts releasing into the environment and causing unintended harm to living organisms warrants investigation. Risk assessment of these materials serves as an important step to allow safe implementation and to avoid irrational fear. Using TiO2 and g‐C3N4 as representative nano‐photocatalysts, this study evaluates their hazard potential in zebrafish. Under simulated solar light, nano‐photocatalysts up to 100 mg L?1 show no acute toxicity to zebrafish embryos due to the protection of chorions. The short‐lived reactive oxygen species generated by nano‐photocatalysts only exert injury to the hatched larvae at and above 50 mg L?1. The input of solar energy, determined by the depth of water, irradiation time, and light intensity, greatly influences the toxicity outcome. Increasing concentrations of natural organic matters contribute positively to the hazard potential at 0–10 mg L?1 while gradually diminishing the hazardous effect above 10 mg L?1. This study demonstrates the importance of nano‐bio interactions and environmental exposure conditions in determining the safety profile of nano‐photocatalysts.  相似文献   

20.
Structural strain due to lattice mismatch is used to promote the formation of a self‐assembled network of antidots in highly epitaxial La2/3Sr1/3MnO3 thin films grown on (001) oriented SrTiO3 substrates by radiofrequency magnetron sputtering. Size, depth, and separation between antidots can be controlled by changing deposition parameters and the miscut angle of the substrate. This morphology exhibits a remarkable magnetic anisotropy and offers unique opportunities for versatile nanostencils for the preparation of nano‐object networks that can be of major relevance for the fabrication of oxide‐based magnetic and magnetoelectronic devices.  相似文献   

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