Latest ArticlesHerein, we utilized nucleic acids induced peptide co-assembly strategy to develop novel nucleic acids induced peptide-based AIE (NIP-AIE) nanoparticles. Strong fluorescent of AIE could be observed when a little amount of nucleic acids was added into the peptide solution, and the intensity could be regulated by the concentration of nucleic acids. This AIE nanoparticle with good biocompatibility could achieve fast cell imaging. It is also proved that the fluorescence intensity of AIE decreased with time, which indicates that the reducible cross-linkers of Wpc peptide by GSH and nanoparticles gradually disintegrate in cell. Based on the different of AIE fluorescence signals which regulated by the formation and disintegration of nanoparticles, this AIE system is expected to be used for real-time monitoring of drug release from peptide-based nano carriers in vivo or in vitro, and may provide a new platform for the construction of other organic AIE nanoparticles.
The saccharification of cellulosic biomass to produce biofuels and chemicals is one of the most promising industries for green-power production and sustainable development. Cellulase is the core component in the saccharification process. Simple and efficient assay method to determine cellulase activity in saccharification is thus highly required. In this work, a boronate-affinity surface based renewable and ultrasensitive electrochemical sensor for cellulase activity determination has been fabricated. Through boronate-sugar interaction, celluloses are attached to the electrode surface, forming the cellulose nano-network at the sensing interface. Cellulase degradation can lead to the variation of electrochemical impedance. Thus, electrochemical impedance signal can reflect the cellulase activity. Importantly, via fully utilizing the boronate-affinity chemistry that enables reversible fabrication of cellulose nano-network, a renewable sensing surface has been firstly constructed for cellulase activity assay. Thanks to interfacial diffusion process of electrochemical sensor, the product inhibitory effect in the cellulase activity assays can be circumvented. The proposed electrochemical sensor is ultrasensitive for label-free cellulase activity detection with a very simple fabrication process, showing great potential for activity screen of new enzymes in saccharification conversion.
An electrochemical amino-azidation of 2-aminostyrene with sodium azide (NaN3) was developed, which can be carried out smoothly in water under metal-free condition, affording a series of 3-azido indolines with high yields.
Luminescent conjugated network polymer is one of the most promising chemo-sensors owing to their good chemical/optical stability and multiple functionalization. Herein, three conjugated network polymers were prepared by using aggregation-induced emission active 1, 1, 2, 2-tetrakis(4-formyl-(1, 1'-biphenyl))-ethane (TFBE) unit as monomer and hydrazine as linker. Through regulating the synthetical condition, the polymeric network can form either uniform two-dimensional azine-linked nanosheets (A-NS), conjugated microporous polymers (A-CMP) or covalent organic frameworks (A-COF). All of these polymers exhibited good stability and high fluorescence quantum efficiency with the quantum yield of 6.31% for A-NS, 5.26% for A-CMP, and 5.80% for A-COF, as well as fast and selective fluorescence quenching response to 2, 4, 6-trinitrophenol (TNP). And the best TNP sensing performance with the Stern-Volmer constants (Ksv) values up to 8×105 L/mol and a detection limit of 0.09 μmol/L was obtained for A-NS. The study explores various strategies to construct conjugated polymers with different nanoarchitectures based on the same building block for sensitive detection of explosives.
A facile preparation strategy was proposed for preparation of compact zeolite LTA membranes on polyethyleneimine (PEI) modified substrates without seeding. Through the functionalization of substrates by using PEI, compact LTA membranes can be formed on various kinds of substrates. A well-intergrown and phase-pure LTA membrane with a thickness of about 3.0 μm is successfully prepared on the α-Al2O3 disk after crystallization for 24 h at 60 ℃. Besides LTA membrane, well-intergrown zeolite FAU membranes can also be formed on PEI-modified α-Al2O3 substrates, suggesting the universality of this strategy. The zeolite LTA membranes synthesized on PEI-modified α-Al2O3 tubes were evaluated for the separation of alcohols/water mixture through pervaporation. The as-synthesized zeolite LTA membranes display high pervaporation performances. For the separation of 10 wt% iso-propanol/water solution at 90 ℃, a high separation factor of 44991 and a water flux of 1.73 kg m-2 h-1 are achieved.
The abnormal aggregation of amyloid-beta (Aβ) has been widely believed to play an important role in the pathogenesis of Alzheimer's disease (AD), which is also recognized as one of the main biomarkers for AD diagnosis. The peptide sequence Lys-Leu-Val-Phe-Phe (KLVFF) is considered as the main driver of the fibrillation of Aβ, which also can be utilized to target Aβ and inhibit its aggregation. In this study, KLVFF and Fmoc-KLVFF fluorescent nanoparticles were self-assembled through zinc coordination and π-π stacking. The recognition of Aβ aggregates including oligomers and fibrils by fluorescent nanoparticles can be realized through aromatic, hydrophobic, and hydrogen-bond interactions. The fluorescent nanoprobes can distinguish Aβ aggregation formats and detect Aβ at the limit of 1 pg/mL (S/N = 3). Hence, the detection of Aβ aggregates by fluorescent peptide nanoparticles has great potential for AD diagnosis and progression prediction.
Using the global particle-swarm optimization method and density functional theory, we predict a new stable two-dimensional layered material: MgSiP2 with a low-buckled honeycomb lattice. Our HSE06 calculation shows that MgSiP2 is an indirect-gap semiconductor with a band-gap of 1.20 eV, closed to that of bulk silicon. More remarkably, MgSiP2 exhibits worthwhile anisotropy along with electron and hole carrier mobility. A ultrahigh electron mobility is even up to 1.29×104 cm2 V-1 s-1, while the hole mobility is nearly zero along the a direction. The large difference of the mobility between electron and hole together with the suitable band-gap suggest that MgSiP2 may be a good candidate for solar cell or photochemical catalysis material. Furthermore, we explore MgSiP2 as an anode for sodium-ion batteries. Upon Na adsorption, the semiconducting MgSiP2 transforms to a metallic state, ensuring good electrical conductivity. A maximum theoretical capacity of 1406 mAh/g, a small volume change (within 9.5%), a small diffusion barrier (~0.16 eV) and low average open-circuit voltages (~0.15 V) were found for MgSiP2 as an anode for sodium-ion batteries. These results are helpful to deepen the understanding of MgSiP2 as a nanoelectronic device and a potential anode for Na-ion batteries.
Multishelled hollow structures have drawn increasing interest because of their peculiar compartmentation environments and physicochemical properties. In this work, deformable double-shelled hollow mesoporous organosilica nanocapsules (DDHMONs) were successfully synthesized by a multi-interfacial etching strategy. The obtained DDHMONs have a double-shelled structure with aninorganic-organic hybrid framework, a uniform outer layer (~320 nm) and inner layer (~180 nm), ordered mesochannels (~2.21 nm), and a large specific surface area (~1233 m2/g). In vitro toxicity tests show that the DDHMONs have excellent biocompatibility when coincubated with human breast cancer cells. In addition, the anticancer substance doxorubicin (DOX) can be highly loaded in DDHMONs (~335 μg/mg). The results from flow cytometry together with confocal laser scanning microscopy show that DOX can be efficiently delivered into MCF-7 cells by DDHMONs, thus improving chemotherapeutic efficiency and demonstrating that DDHMONs have potential nanomedicine applications as anticancer agents.
Most recently, cobalt sulfide (CoS) nanospheres (NSs) have been demonstrated as an ideal high-efficient photothermal agent for tumor elimination. However, the surface of CoS NSs is lack of functional chemical groups or active radicals to incorporate therapeutic agents, which tremendously hinders their versatile utilization in medical field. Here, surface activation of CoS NSs was realized through the growth of polydopamine (PDA) in situ via alkaline-triggered polymerization. Upon the formation of CoS@PDA NSs, thiol-polyethylene glycol (SH-PEG) and chemotherapeutic agent of doxorubicin (DOX) were loaded onto the particle surface by means of π-π electrostatic interaction and Michael addition reactions. As-synthesized CoS@PDA/PEG/DOX (CoPPD) NSs exhibited an admirable photothermal property and high loading capacity of DOX (44.6%). Furthermore, drug release can be accelerated under a more acidic pH condition mimicking tumor microenvironment (TME), ascribed to the protonation of amino group in DOX molecules. Finally, a strong chemotherapeutic-enhanced photothermal therapeutic effect was demonstrated toward solid tumor under near-infrared (NIR) light irradiation without causing significant systemic toxicity. In this regard, this paradigm may offer valuable guidance for the design of multifunctional CoS-based nanoagents for medical treatment.
Size-controlled flow synthesis of nanoporous particles are of considerable interest for future industrial applications, however, is facing challenges due to lack of in-situ method for size-characterization in fluidic environment. We present that ultraviolet-visible (UV–vis) absorption spectroscopy can be integrated into a flow-synthesis system which was produced by femtosecond laser micromachining. The shift of the absorption peak position of the ex-situ and in-situ UV–vis spectra correlates to variation of size of porous metal-organic frameworks crystals. ZIF-67 crystals with a size in the range from 200 nm to 1025 nm are fabricated with the assistance of tri-ethylamine under monitoring of in-situ UV–vis spectra. The ZIF-67 crystals are converted into nanoporous carbons particles with controlled sizes. These materials show size-dependent performance in Na-ion battery and size-independent performance in metal/H2O seawater battery.
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