Latest ArticlesCysteine (Cys) plays a pivotal role in many physiological and pathological processes, including detoxification and protein synthesis. The abnormal levels of Cys are linked to many diseases. In this study, a novel red-emitting off-on fluorescent probe Cys-TCF was masterly constructed for discriminative detection of Cys. After a series of experimental assessment, Cys-TCF displayed higher selectivity and sensitivity for Cys over other biothilols with a low detection limit (0.04 μmol/L). More notably, the probe was also successfully applied to image Cys in live cells and live zebrafishes with low cytotoxicity.
Circulating tumor DNA (ctDNA), carrying tumor-specific sequence mutations, is a promising biomarker for classification, diagnosis and prognosis of cancers. However, there is still a great challenge in discriminating single-base difference between ctDNA and its coexisting analogue (normal circulating DNA, ncDNA) at a serum sample. A locked nucleic acid (LNA) probe combined with α-HL nanopore sensor was designed, which achieved a high signal-to-background ratio (SBR) of ~8.34×103, as well as a significant discrimination capability (~12.3 times) of single-base difference. The accurate discrimination strategy is label-free, convenient, selective and sensitive, which has great potential in the early diagnosis of diseases and biomedical research fields.
With the rapid growth in electronic device performance, there has been an increasing demand for thermally conductive polymer composites to handle the thermal management issue, thus contributing to the great importance to develop the graphene framework, which is evaluated as the most promising reinforcements for enhancing the thermal conductivity of polymer. Vacuum filtration is a common method to fabricate graphene framework, whereas, it is available to prepare a framework with centimeter-scale thickness by filtrating the graphene-water dispersion, due to the fact of sample cracking caused by the mismatch of surface tension between graphene and water. In this work, a surfactantassisted strategy was proposed by adjusting the surface tension of the water close to that of graphene first, then performing a conventional filtration process, to fabricate graphene framework. As a result, a thick graphene framework (thickness: 3 cm) was successfully prepared, and after embedding into epoxy, the framework endows the composite (13.6 wt%) with a high in-plane thermal conductivities of 12.4 W/mK, which is equivalent to ≈64 times higher than that of neat epoxy. Our method is simple and compatible with the conventional filtration process, suggesting great potential for the mass-production of graphene framework to meet the practical application requirements.
Two A-B-C type conjugated amphiphilic triblock fullerene derivatives C60-2HMTPB and C60-2EHTPB were obtained in multi steps synthesis with three different blocks, and the amphiphilic diblock molecular C60-4TPB was also preferred as a reference. When as modifying layer on zinc oxide (ZnO), the three fullerene derivatives can all reduce the work function of ZnO via modulation of the interfacial dipoles and lead a better electrical coupling. As introducing treatment of toluene, the obvious self-assembly of fullerene derivatives were observed, which were supported by X-ray diffraction and contact angle of water measurement. Base on PTB7-Th:PC71BM system, the inverted organic solar cells devices with structure of ITO/ZnO/fullerene derivatives/PTB7-Th:PC71BM/MoO3/Al got power conversion efficiencies of 8.62%, 8.83% and 9.00% for C60-4TPB, C60-2HMTPB and C60-2EHTPB, respectively, compared 8.13% of devices with bare ZnO. The result of conjugated amphiphilic triblock fullerene derivatives provides a straightforward approaching by simultaneously modulating the morphology and interfacial work function of ZnO, which can also lead high performance in optoelectronic devices.
Undesired adsorption of proteins brings big troubles to marine structures. The settled proteins change the physical and chemical properties of the surfaces, which allow marine fouling organisms to settle down on the structures. Therefore, to understand the adsorption mechanism of proteins is very helpful to find an environment-friendly solution against biofouling. Many approaches have been developed to study protein adsorption, but most of them are insufficient to give the chemical interaction information between proteins and surfaces. Fourier transform infrared spectroscopy with attenuated total reflection (FTIR-ATR) is an efficient, fast and non-destructive method for in situ surface measurement, which greatly minimizes the interference of water to infrared spectra, because of the very small depth of penetration of the evanescent wave. In this paper, an in situ FTIR-ATR technology was used to investigate the adsorption process of trypsin on a bare ZnSe surface and on a TiO2 coated ZnSe surface, and the effect of calcium cation strength and ultraviolet light irradiation on the secondary structure of trypsin were also evaluated. FTIR spectra of trypsin showed that Amide Ⅰ band red shift and Amide Ⅱ band blue shift in aqueous environment on both surfaces compared with the dry trypsin powder, and the addition of calcium cations further changed the Amide bands position, which indicated that the change of the secondary structure could be interfered by the environment. The hydrogen bond formation between water and trypsin, the interaction between surface and trypsin, the interaction between hydrated calcium cations and trypsin, are major factors to change the secondary structure of trypsin, and UV light irradiation also showed its influence for the secondary structure.
It is urgent to find a technology accurately to better diagnose and treat to brain tumor. Eu-doped Gd2O3 nanorods (Eu-Gd2O3 NRs) with paramagnetic and fluorescent properties were conjugated with doxorubicin (Dox) and chlorotoxin (CTX) via PEGylation, hydrazone bond and sulfur bond (named as CTXNRs-Dox), and these NRs could release more Dox in lower pH environment. The results of cell experiments indicated that CTX-NRs-Dox had obvious targeting and toxic effects on U251 cells, as well as good fluorescence imaging behavior. The orthotopic glioma-transplanted mice models were constructed via the intracranial injection of glioma cells (U87MG). The result of experiments after the tail-vein injection of the prepared NRs suggested that CTX-NRs-Dox could target to brain tumors via the long-time blood circulation, leading to their obvious contrast enhancement of MR imaging of the intracranial tumor and their significant inhibitory effect on the growth and metastasis of brain tumors. A mechanism of synergistic effect of CTX-NRs-Dox on targeting and inhabiting the brain tumor was proposed. Our research suggested that CTX-NRs-Dox had potential application prospect in the detection and treatment of glioma.
Hard carbon is promising anode for potassium-ion batteries (PIBs), however, the poor rate capability hinders its development as potential anode. To address this question, we design a sulfur-doped porous hard carbon (S-HC) for PIBs through the combination of structural design and composition adjustment. The as-designed S-HC exhibits a long cycling life with ~191 mAh/g after 300 cycles at 1 A/g, and an excellent rate capability with ~100 mAh/g at 5 A/g, which was attributed to its structural characteristics and compositions. The S-HC demonstrates to be promising anode in the future.
A novel channel-wall engineering strategy of the porous materials cationic covalent organic frameworks (COFs) is established based on rapid microwave-assisted anion exchange reaction and utilized to prepare a set of new COFs. Due to the interaction between the carbon dioxide (CO2) and the acetate anion, the resulting SJTU-COF-AcO shows greatly enhanced carbon dioxide capacity up to 1.7 times of the pristine COF. The effect of the counter anions to CO2 capacity in the cationic COFs is investigated for the first time, which demonstrates that our channel-wall engineering strategy is a promising way to tailor the property of COFs for high CO2 capacity.
Fourteen avermectin B2a aglycon derivatives were designed and synthesized after removing the oleandrose disaccharide of avermectin B2a. Their structures were characterized by 1H NMR, 13C NMR, HMRS. Preliminary bioassays indicated that these compounds exhibited good insecticidal activity against diamondback moth at 200 mg/L, with mortality no less than 90%. Compounds 10b, 12a, 12c, 17 demonstrated good acaricidal activity against the adult mites, larvae, and good inhibition rate of hatching to mite eggs of Tetranychus cinnabarinus. Compounds 5, 10b, 10c exhibited excellent fungicidal activity against fourteen fungal pathogens in vitro. 3D-QSAR analysis showed that the fungicidal activity of avermectin B2a aglycon derivatives would be increased when a negatively charged and bulky group was introduced at 13-position, which will be instructive for the further modification of avermectin B2a aglycon.
As a kind of stimuli-responsive materials, the disulfide-containing material has received a tremendous amount of interest. A novel functional disulfide-containing waterborne polyurethane (DS-WPU) nanoemulsion was prepared via a one-step in situ phase inverse emulsification technique and its reducing-responsive property was investigated using dithiothreitol as the reductant. Results showed that the DS-WPU nanoemulsion had a uniform particle size in nanoscale and a good film-forming characteristic, and the DS-WPU latex film exhibited great responsiveness along with a self-assembled behavior in the reducing environment to form WPU emulsion again, including a long-to-short process of the polymer chains.
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