Zeolitic imidazole frameworks (ZIFs) are an emerging class of functional porous materials with promising biomedical applications such as molecular sensing and intracellular drug delivery. We report ...herein the first example of using nanoscale ZIFs (i.e., ZIF-90), self-assembled from Zn2+ and imidazole-2-carboxyaldehyde, to target subcellular mitochondria and image dynamics of mitochondrial ATP in live cells. Encapsulation of fluorescent Rhodamine B (RhB) into ZIF-90 suppresses the emission of RhB, while the competitive coordination between ATP and the metal node of ZIF-90 dissembles ZIFs, resulting in the release of RhB for ATP sensing. With this method, we are able to image mitochondrial ATP in live cells and study the ATP level fluctuation in cellular glycolysis and apoptosis processes. The strategy reported here could be further extended to tune nanoscale ZIFs inside live cells for targeted delivery of therapeutics to subcellular organelles for advanced biomedical applications.
In situ regeneration of the enamel‐like structure of hydroxyapatite (HAp) crystals under oral conditions is significant for dental caries treatment. However, it is still a challenge for dentists to ...duplicate the elegant and well‐aligned apatite structure bonding to the surface of demineralized enamel. A biocompatible amelogenin‐inspired matrix, a phase‐transited lysozyme (PTL) film mimicking an N‐terminal amelogenin with central domain (N‐Ame) combined with synthetic peptide (C‐AMG) based on the functional domains of C‐terminal telopeptide (C‐Ame) is shown here, which is formed by amyloid‐like lysozyme aggregation at the enamel interface through a rapid one‐step aqueous coating process. In the PTL/C‐AMG matrix, C‐AMG facilitated the oriented arrangement of amorphous calcium phosphate (ACP) nanoparticles and their transformation to ordered enamel‐like HAp crystals, while PTL served as a strong interfacial anchor to immobilize the C‐AMG peptide and PTL/C‐AMG matrix on versatile substrate surfaces. PTL/C‐AMG film‐coated enamel induced both of the in vivo and in vitro synthesis of HAp crystals, facilitated epitaxial growth of HAp crystals and recovered the highly oriented structure and mechanical properties to levels nearly identical to those of natural enamel. This work underlines the importance of amyloid‐like protein aggregates in the biomineralization of enamel, providing a promising strategy for treating dental caries.
An amyloid‐like proteinaceous nanofilm entrapping peptide can mimic the amelogenin matrix in nature, mediating the oriented array of amorphous calcium phosphate nanoparticles and their transformation to ordered enamel‐like hydroxyapatite (HAp) crystals. This technology can reproduce the growth of ordered HAp crystals, with mechanical strength nearly identical to that of natural enamel, thus providing a promising strategy for treating dental caries.
The rise of antibiotic resistance demands the acceleration of molecular diversification strategies to inspire new chemical entities for antibiotic medicines. We report here on the large-scale ...engineering of ribosomally synthesized and post-translationally modified antimicrobial peptides carrying the ring-forming amino acid lanthionine. New-to-nature variants featuring distinct properties were obtained by combinatorial shuffling of peptide modules derived from 12 natural antimicrobial lanthipeptides and processing by a promiscuous post-translational modification machinery. For experimental characterization, we developed the nanoFleming, a miniaturized and parallelized high-throughput inhibition assay. On the basis of a hit set of >100 molecules, we identified variants with improved activity against pathogenic bacteria and shifted activity profiles, and extrapolated design guidelines that will simplify the identification of peptide-based anti-infectives in the future.
Exposure of dentinal tubules (DTs) leads to the transmission of external stimuli within the DTs, causing dental hypersensitivity (DH). To treat DH, various desensitizers have been developed for ...occluding DTs. However, most desensitizers commercially available or in development are only able to seal the orifices, rather than the deep regions of the DTs, thus lacking long‐term stability. Herein, it is shown that the fast amyloid‐like aggregation of lysozyme (lyso) conjugated with poly(ethylene glycol) (PEG) (lyso‐PEG) can afford a robust ultrathin nanofilm on the deep walls of DTs through a rapid one‐step aqueous coating process (in 2 min). The resultant nanofilm provides a highly effective antifouling platform for resisting the attachment of oral bacteria such as Streptococcus mutans and induces remineralization in the DTs to seal both the orifices and depths of the DTs by forming hydroxyapatite (HAp) minerals in situ. Both in vitro and in vivo animal experiments prove that the nanofilm‐coated DTs are occluded with a depth of over 60 ± 5 µm, which is at least 6 times deeper than that reported in the literature. This approach thus demonstrates the concept that an amyloid‐like proteinaceous nanofilm can offer an inexpensive, rapid, and efficient therapy for treating DH with long‐term effect.
A general surface modification strategy based on fast amyloid‐like aggregation of lysozyme conjugated with poly(ethylene glycol) (lyso‐PEG) is developed. The lyso‐PEG oligomers rapidly attach on dentin tubules in 2 min, resist biofilm formation, and induce in‐depth remineralization of the dentine tubules. This approach offers an inexpensive, rapid, and efficient therapy for treating dental hypersensitivity with long‐term stability.
Herein, the hydrophobic carboxyl-functionalized ionic liquid (IL-COOH) was encapsulated into the prepared Fe3O4@Zr-MOFs, and the novel water-stable IL-COOH/Fe3O4@Zr-MOF nanocomposites were first ...synthesized. The polydopamine-functionalized Fe3O4 was introduced to construct the core–shell structure via layer-by-layer modification, and the controlled growth of Zr-MOFs was achieved, which realized the adjustment of charged properties of nanocomposites and simplified the adsorption or extraction process. The IL-COOH/Fe3O4@Zr-MOFs were fully studied by IR, HNMR, XRD, N2 adsorption–desorption isotherms, TEM, EDS mapping, VSM, and so on. Then, they were employed for the selective adsorption and detection of fluoroquinolone antibiotics (FQs). The adsorption isotherms and kinetics demonstrated that the adsorption process followed a pseudo-second-order kinetic model and the Langmuir isotherm model. Among them, IL-COOH/Fe3O4@UiO-67-bpydc showed the best adsorption performance, and the maximum adsorption capacity of ofloxacin was 438.5 mg g–1. Coupled magnetic solid-phase extraction with HPLC-DAD, a convenient, sensitive, and efficient method for extraction and detection of FQs in environmental water, was developed based on IL-COOH/Fe3O4@UiO-67-bpydc. The recoveries of environmental water were ranging from 90.0 to 110.0%, and the detection limits were lower than 0.02 μg L–1. The novel functionalized composites served as solid-phase adsorbents and liquid-phase extractants. This study also provided a promising strategy for designing and preparing multi-functionalized nanocomposites for the removal or detection of pollutants in environmental samples.
Direct selective and sensitive sensing of pyrophosphate ion (PPi) in synovial fluid of arthritis patients is of great importance because of its crucial roles in the diagnosis and therapy of arthritic ...diseases. In this study, we demonstrate a sensitive and selective method for PPi sensing in synovial fluid of arthritis patients with gold nanoparticles (Au-NPs) as the signal readout based on the competitive coordination chemistry of Cu2+ between cysteine and PPi. Initially, Au-NPs stabilized with cysteine are red in color and exhibit absorption at 519 nm in the UV–vis spectrum. The addition of an aqueous solution of Cu2+ to the Au-NPs dispersion containing cysteine causes the aggregation of Au-NPs, resulting in the wine red-to-blue color change and the appearance of a new absorption at 650 nm in the UV–vis spectrum of the Au-NPs dispersion. The subsequent addition of PPi to the Au-NPs aggregation well solubilizes the aggregated Au-NPs with the changes in both the color and the UV–vis spectrum of the Au-NPs dispersion. These changes are ascribed to the higher coordination reactivity between Cu2+ and PPi than that between Cu2+ and cysteine. On the basis of this, the concentration of PPi can be visualized with the naked eyes through the blue-to-wine red color change of the Au-NPs dispersion and quantitatively determined by UV–vis spectroscopy. Under the optimized conditions, the ratio of the absorbance at 650 nm (A 650) to that at 519 nm (A 519) shows a linear relationship with PPi concentration within a concentration range from 130 nM to 1.3 mM. The method demonstrated here is highly sensitive, free from the interference from other species in the synovial fluid, and is thus particularly useful for fast and simple clinic diagnosis of arthritic diseases.
Postoperative intractable hiccups slow patient recovery and generate multiple adverse effects, highlighting the importance of investigating the pathogenesis and terminating the hiccups in a timely ...manner. At present, medical and physical therapies account for the main treatments. We encountered a case in which postoperative intractable hiccups after biliary T-tube drainage removal ceased with the application of an ultrasound-guided block of the unilateral phrenic nerve and stellate ganglion. No complications developed, and the therapeutic effect was remarkable. To our knowledge, this approach has not been reported to date. Simultaneously blocking the phrenic nerve and stellate ganglion may be a treatment option for intractable hiccups.
In this study, a high effective phosphorus‐containing flame retardant (DOP‐DDM) was synthesized using phenylphosphonic dichloride, p‐hydroxybenzaldehyde, 9,10‐dihydro‐9‐oxa‐10‐phosphaphenan‐ ...threne‐10‐oxide (DOPO) and 4,4′‐diaminodiphenyl methane (DDM) as raw materials. The chemical structure of DOP‐DDM was confirmed by Fourier transform infrared spectroscopy (FT‐IR), 1H nuclear magnetic resonance (1H NMR) and 31P nuclear magnetic resonance (31P NMR). The epoxy resin (EP) material with 4.7 wt% DOP‐DDM (EP‐4.7) can reach V‐0 degree in UL 94 test and has LOI value as high as 33.5%. If neat EP (EP‐0) material is used as a control, even if the loading of DOP‐DDM in the flame‐retarded EP material reached 7.6 wt%, the transmittance can reach 96.8% of EP‐0. From cone combustion (CC) test, the peak of heat release rate (pHRR), total heat release (THR) and total smoke release (TSR) values of EP‐4.7 material were decreased in comparison to those of EP‐0. Compared with EP‐0 material, differential scanning calorimetry (DSC) and dynamic thermo mechanical (DMA) results showed that the glass transition temperature of EP‐4.7 material slightly increased, and the storage modulus (E′) and loss modulus (E′′) increased 65.7% and 47.3%, respectively. The morphology and graphitization degree of residual char after CC test were measured by SEM and Raman spectroscopy, respectively. Concurrently, the gas components of EP‐4.7 material were well analyzed by thermogravimetric analysis FTIR. All these results demonstrated that the DOP‐DDM played a role in gas‐phase and condensed‐phase.
► Cu and Pb were the most leachable heavy metals in WPCBs according to TCLP and SPLP. ► Penta-BDE congeners were dominated in all extracts. ► High dissolved organic matter condition promoted the BFRs ...leaching rate. ► Leaching from WPCBs was a significant emission source of BFRs in landfill.
Leaching assessment on five heavy metals (copper, zinc, lead, nickel and cadmium) and two brominated flame retardants (BFRs), polybrominated diphenyl ethers (PBDEs) and tetrabromobisphenol A (TBBPA), from waste printed circuit boards (WPCBs) were conducted using various leaching methods. The mean leaching concentrations of copper were the highest in both toxicity characteristic leaching procedures (TCLP) and synthetic precipitation leaching procedures (SPLP) tests at 8.6mg/L and 1.1mg/L, while only lead (6.2mg/L) exceeded the TCLP criteria and Chinese EPA regulatory limit (both 5.0mg/L). However, PBDEs and TBBPA were not detected in TCLP and SPLP tests. Then the BFRs leaching trends and potential leachabilities were further investigated in actual landfill leachates using a modified method. Leaching characteristics that fast-leaching initially followed by slow-desorption over time were generally observed. In landfill leachate tests, the highest leaching concentrations of PBDEs and TBBPA were determined at 30.39 and 12.27μg/L. Meanwhile, the highest leaching rates were estimated to reach 0.08% and 1.00%, respectively, which were significantly influenced by the dissolved organic carbon contents of extracts, the hydrophobicities of target BFRs and the specific surface areas of WPCBs materials. These results proved that leaching from WPCBs was a significant emission source of BFRs in landfill and electronic waste recycling dumpsite.
Poly(butyl acrylate) was prepared by the free radical polymerization of butyl acrylate as an initiator in the presence of 2,2′-Azoisobu-tyronitrile (AIBN) and the average molecular weight, ...polydispersity and thermal stability were evaluated. PLA and PBA were melt blended using a Haake Rheometer, and the light transmission, thermal properties, dynamic rheological properties, mechanical properties, phase morphology of blends and toughening mechanism were investigated. Dynamic rheology, SEM and DSC results show that the PLA is partial miscible with PBA. The PBA component improved the crystallization ability of PLA and the crystallinity of PLA increased with content of PBA (<15
wt.%). With the increase of PBA, the tensile strength and modulus of the blend decreased slightly while the elongation at break and toughness were dramatically increased. With the addition of PBA, the failure mode changes from brittle fracture of neat PLA to ductile fracture of the blend. Rheological results revealed the complex viscosity and melt elasticity of the blends decreased with increasing content of PBA and phase segregation occurred at loading above 11
wt.% PBA. UV–vis light transmittance showed that PLA/PBA blends with a high transparency, and the transmittance decreased with the amount of PBA.
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