Latest ArticlesExosomes (EXOs) have showed great potential in regenerative medicine. The separation of EXOs from complex biological media is essential for the down-stream applications. Herein, we report a deoxyribonucleic acid (DNA)-based micro-complex (DMC) containing polyaptamers, which realized the specific separation of EXOs from cell culture media and the significant promotion of wound healing. The synthesis of DMCs was based on a biomineralization process via rolling circle amplification (RCA) under the catalysis of phi29 DNA polymerase. To endow DMCs with the ability to capture EXOs, the DNA template of RCA was integrated with complementary sequence of aptamer that specifically recognized the CD63 proteins on EXOs. The obtained DMCs contained polyaptamers that can specifically capture the EXOs in cell culture media. The EXOs-capturing DMCs were collected by centrifugation, achieving the separation of EXOs. Mesenchymal stem cell (MSC)-derived EXOs (MSC-EXOs) were separated by this DMC-based strategy, and the separated MSC-EXOs significantly enhanced the migration ability of cells. In particular, the significant therapeutic efficacy of the DMCs with MSC-EXOs was verified in full-thickness wound excision mouse models, in which the wounds completely healed in 10 days. We envision that this DMC-based separation strategy can be a promising route to promote the development of EXOs in biomedicine.
The microphases and miscibility in binary curcumin (Cur) solid dispersions (SDs) with amorphous polyvinylpyrrolidone K30 (PVP K30) and semi-crystalline poloxamer (P407) and poly(ethylene glycol) 6000 (PEG6000) as carriers were investigated by fluorescence contrasting utilizing confocal laser scanning microscopy. A super sensitive fluorophore P4 with typical aggregation-caused quenching properties was employed to stain the continuous polymer phases and contrasted with the autofluorescence of the model drug Cur. In addition, differential scanning calorimetry (DSC) and powder X-ray diffraction (PXRD) were utilized to assist in explanation of the fluorescence results. In all three SD systems, there is always a homogenous polymer phase stained by P4 and it is difficult to adulterate Cur crystals by P4. Cur-enriched rather than polymer-enriched domains could be detected. In the Cur-PVP K30 system, Cur exists in an amorphous form at a Cur loading level of 50% and below, while Cur crystallines phase out and continuously grow with the increase of Cur loading from 60% to 90%. The phase behaviors in the Cur-P407 and Cur-PEG 6000 systems are similar but with minor differences. In both systems, Cur phases out as clusters of drug-enriched domains at a loading level of 20% and below, which however cannot be correlated with crystallization, as evidenced by both DSC and PXRD. There is a transition from an amorphous to a crystalline state from 20% to 30% Cur loading, above which Cur crystallines can be detected. It is interesting that a co-mix phase of both Cur- and PEG 6000-enriched domains can be identified at Cur loading levels of 10% and less. Taking together, it is concluded that contrasting Cur autofluorescence with the signals of P4 proves to be a functional strategy to reveal multiple phases in the binary SD systems investigated.
To solve the volume expansion and poor electrical conductivity of germanium-based anode materials, Ge/rGO/CNTs nanocomposites with three-dimensional network structure are fabricated through the dispersion of polyethylene-polypropylene glycol (F127) and reduction of hydrogen. An interesting phenomenon is discovered that F127 can break GeO2 polycrystalline microparticles into 100 nm nanoparticles by only physical interaction, which promotes the uniform dispersion of GeO2 in a carbon network structure composed of graphene (rGO) and carbon nanotubes (CNTs). As evaluated as anode material of Lithium-ion batteries, Ge/rGO/CNTs nanocomposites exhibit excellent lithium storage performance. The initial specific capacity is high to 1549.7 mAh/g at 0.2 A/g, and the reversible capacity still retains 972.4 mAh/g after 100 cycles. The improved lithium storage performance is attributed to that Ge nanoparticles can effectively slow down the volume expansion during charge and discharge processes, and three-dimensional carbon networks can improve electrical conductivity and accelerate lithium-ion transfer of anode materials.
Strategic active site organization is imperative for the advancement of effective and long-lasting catalysts of oxygen reduction reactions. However, the controllable multi-active site design is a highly intricate topic for catalyst synthesis. Employing pre-trapping and post-activation strategy, Fe-N bonding structure and S, Se functionalized heteroatom are integrated into a conductive porous carbon. In this process, the nitrogen-abundant polymer 1,3,5-triformylbenzene-tris(4-aminophenyl)benzene (Tf-TAPA) adsorbs Fe3+ under the intrinsically metal anchoring ability of N atoms and simultaneously in-situ assembles long-chain thiophene-S. Subsequently, the Fe3+ is transformed into Fe-Nx moieties with the conversion of the organic chain to incompletely graphitized carbon. Furthermore, the alteration of the electronic configuration achieved through the introduction of dual-atom S and Se leads to a pronounced enhancement in catalytic efficiency. Benefitting from the Fe-Nx bonding structure, dense structural defects, and conductive carbon networks, the resultant Fe-S,Se/NCNs possesses a positive half-wave potential of 0.86 V and a 90% current retention rate, outstripping the Pt/C benchmark. Moreover, the liquid and flexible ZAB driven by Fe-S,Se/NCNs achieves large power densities of 259.7 and 164.7 mW/cm2, respectively. This study provides a new comprehension in developing an efficient and stable M-N-C oxygen electrocatalyst.
Fe-N-C materials have received increasing attention, due to its distinctive catalytic activity. However, the Fe-N coordination number dependence of catalytic ability and mechanism for H2O2 activation remain elusive. Herein, a series of Fe-N-C heterogeneous Fenton-like catalysts with different Fe-N coordination number were prepared for tetracycline degradation. The results demonstrated that samples with Fe-N4 structure exhibited high activity. The excellent performance was mainly ascribed to the high adsorption capacity and the formation of superoxide radicals (•O2−) catalyzed by Fe linked to pyridinic nitrogen. The intermediates and degradation pathways of tetracycline degradation by Fe-N-C/H2O2 system were analyzed by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). Furthermore, we applied our Fe-N-C catalysts to treat simulated pharmaceutical wastewater with high tetracycline degradation capacity despite high concentrations of organic matter such as oxalic acid and various ionic interferences. Our work reveals the dependence of the activation H2O2 on the Fe-N coordination environment and the degradation mechanism of these catalysts. It provides insights into the prospects for tuning the catalyst in practical applications.
Niduenes A−F (1−6), six novel sesterterpenoids with unprecedented 5/5/5/5/6 pentacyclic ring skeleton were isolated from endophytic fungus Aspergillus nidulans. Compounds 1 and 2 represent the first examples of aromatic pentacyclic sesterterpenoids. Their structures and configurations were elucidated by spectroscopic data and single-crystal X-ray diffraction analyses. Compound 4 demonstrated potent resensitization of SW620/AD300 cells to paclitaxel (PTX). Rhodamine 123 accumulation assay and docking analysis further support that 4 inhibitory the efflux function of P-glycoprotein (P-gp).
Vanadium pentoxide (V2O5) with a layered structure is of great interest in the field of electrochromic (EC) due to its abundance of color variations. However, there are still a series of problems such as slow ion diffusion, poor electronic conductivity and cyclic stability in the reaction process. Herein, we successfully prepared a stable and fast multi-color electrochromic material V2O5-PEDOT by a simple "one-pot" method. The layer space of V2O5 could be tuned by 3,4-ethylenedioxythiophene (named V2O5-PEDOT) during the dissolution and recrystallization of vanadium oxide. The expanded layer spacing facilitates rapid ion insertion and extraction. PEDOT serves as an internal conductive pillar to improve the overall conductivity of the material. The obtained intercrossing structure of the nanobelts shortens the ion diffusion distance and ensures electrolyte penetration. The V2O5-PEDOT exhibits the fast response time (1.1 s for coloration and 3.5 s for bleaching at 422 nm), high optical contrast (ΔT = 45% at 422 nm and ΔT = 35.2% at 1000 nm), great coloration efficiency (CE = 97.1 cm2/C), and high cyclic stability (86% preserved after 3000 cycles). The electrochromic devices (ECD) were successfully assembled by using V2O5-PEDOT films as ion storage layers and electrochromic layers, demonstrating remarkable performance.
High-efficiency hydrogen production through photoelectrochemical (PEC) water splitting has emerged as a promising solution to address current global energy challenges. Ⅲ-nitride semiconductor photoelectrodes with nanostructures have demonstrated great potential in the near future due to their high light absorption, tunable direct band gap, and strong physicochemical stability. However, several issues, including surface trapping centers, surface Fermi level pinning, and surface band bending, need to be addressed. In this work, enhanced photovoltaic properties have been achieved using gallium nitride (GaN) nanowires (NWs) photoelectrodes by adopting an alkaline solution surface treatment method to reduce the surface states. It was found that surface oxides on NWs can be removed by an alkaline solution treatment without changing the surface morphology through X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and other characterization methods. These findings provide new insights to the development of high-efficiency photoelectrodes for new energy source applications.
Highly selective and remotely communicable nitrogen dioxide (NO2) sensing may contribute to future Internet of Things in environmental monitoring. However, room-temperature NO2 sensing materials such as carbon materials is still less than satisfactory due to their insensitive interaction with target gas. Here, polyethylene imine functionalized three-dimensional (3D) carbon framework (PEI/C framework) has been developed for enhanced selective NO2 sensing, via combined template synthesis and subsequent doping. Typically, the 3D PEI/C framework is observed porous shape with irregular coating. Beneficially, the response of C framework to NO2 increases while those of interfering gases decrease after being functionalized with PEI. Remarkably, the sensor prototypes show a 100 ppb-concentration detection limit at room temperature. Theoretically, such excellent NO2 sensing is attributed to the large specific surface ratio of porous 3D PEI/C framework, in which PEI serves as an active layer for target NO2, while a passivated one for interfering gases. Practically, such PEI/C framework sensor prototype is simulated for NO2 sensing device and communicated with a smartphone, showing great potential in future intelligent environmental monitoring.
Hydrogen-bonded organic frameworks (HOFs) are a promising candidate for optical sensing, but the lack of effective design strategies poses significant challenges to the construction of HOFs for organic acid sensing. In this work, the first HOF for organic acid sensing is reported by constructing a multiple-pyridine carbazole-based dense HOF, namely HOF-FJU-206, from a tripyridine-carbazole molecular 3,6-bis(pyridin-4-yl)-9-(4-(pyridin-4-yl)phenyl)-9H-carbazole (CPPY) with carbazole center for luminescence, pyridyl sites for its responsive of hydrogen proton, and narrow channels in the dense framework for the diffusion of hydrogen protons. HOF-FJU-206 exhibits differential responsively fluorescence sensing and recovery properties to formic, acetic, and propionic acids with different molecular sizes and pKa value (acid dissociation constant). The dissociation degree of various acids can be determined by analyzing the slope of changes in both peak wavelength and intensity of in-situ fluorescence, which easily enables the dual-corrective recognition of different acids. The varying degree of protonation at pyridine sites is proved to be the reason for differential sensing of various acids, as demonstrated by 1H NMR spectra, X-ray photoelectron spectroscopy (XPS) characterization, and modeling studies.
No. 86 Xueyuan South Road, Haidian District, Beijing
010-62199257
qkjq@cast.org.cn
Copyright © 2025 China Association for Science and Technology. All rights reserved. For all open access content, the relevant licensing terms apply.
Sponsored by the Office of the Leading Group for Cybersecurity and Informatization of CAST, and supported by Science and Technology Review Publishing House
