Latest ArticlesExosome and inclusive cargoes have manifested significant function in different biological events. In particular, glycopeptides in exosome are closely associated with occurrence and development of various diseases. Developing advanced tools is highly desired to enrich glycopeptides from exosomes, and enrich exosomes from complex biological samples as well. In this work, integration of L-cysteine and titania onto the surface of magnetic nanoparticles is designed to realize the coefficient affinity towards exosomes and inclusive glycopeptides. Benefiting from the synergistic affinity, we separate exosomes from human urine concentrate directly, which was proved by the detection of three typical antigen markers of exosomes. Furthermore, hardly any exosomes remained on materials after ultrasonication, which confirmed the good capture performance of Fe3O4@TiO2@L-Cys and high release effect of direct lysis. Moreover, 146 glycopeptides corresponding to 77 glycoproteins were successfully identified from captured exosomes. These satisfactory results will inspire more efforts to be devoted to this field and will be extremely helpful to in-depth information excavation of biological markers, especially disease-related ones, through exosomes and inclusive glycopeptides.
It is essential to develop efficient electrocatalysts to generate hydrogen from water electrolysis for hydrogen economy. In this work, platinum (Pt) and nickel (Ni) co-doped porous carbon nanofibers (Pt/Ni-PCNFs) with low Pt content were prepared via an electrospinning, carbonization and galvanic replacement reaction. Because of the high electrical conductivity, abundant electrochemical active sites and synergistic effect between Pt and Ni nanoparticles, the optimized Pt/Ni-PCNFs catalyst shows an excellent HER activity with overpotentials of 20 mV in 0.5 mol/L H2SO4 and 46 mV in 1 mol/L KOH at a current density of 10 mA/cm2. Furthermore, over 35-h long-term stability has been achieved without significant attenuation. This work provides a simple route to prepare highly efficient electrocatalysts for water splitting and has great prospects in the field of renewable energy.
Screening of foodborne pathogens is important to prevent contaminated foods from their supply chains. In this study, a portable detection device was developed for rapid, sensitive and simple detection of viable Salmonella using a finger-actuated microfluidic chip and an improved recombinase aided amplification (RAA) assay. Improved propidium monoazide (PMAxx) was combined with RAA to enable this device to distinguish viable bacteria from dead ones. The modification of PMAxx into dead bacteria, the magnetic extraction of nucleic acids from viable bacteria and the RAA detection of extracted nucleic acids were performed using the microfluidic chip on its supporting device by finger press-release operations. The fluorescent signal resulting from RAA amplification of the nucleic acids was collected using a USB camera and analyzed using a self-developed smartphone App to quantitatively determine the bacterial concentration. This device could detect Salmonella typhimurium in spiked chicken meats from 1.3 × 102 CFU/mL to 1.3 × 107 CFU/mL in 2 h with a lower detection limit of 130 CFU/mL, and has shown its potential for on-site detection of foodborne pathogens.
Graphene-polymer composites have attracted great attention as sensing materials due to their tailorable electrical conductivity, physicochemical properties, and sensitivity to geometric and functional changes. Herein, we report the first example of cylindrical monolithic polyimine vitrimer/graphene composites with excellent mechanical, compressive, rehealable and recyclable, and piezoresistive properties via simple infiltration of polymer monomers into the pores of graphene aerogel followed by thermal curing. The composites exhibit excellent durable compressibility (negligible reduction in the compression properties even after 3000 consecutive compression cycles), rapid recovery to the original size upon stress released, high compressive strength (up to 1.2 MPa), and high conductivity (up to 79 S/m). Excellent piezoresistive properties were observed, displaying consistent and reliable change of the electrical resistance with the compression ratio. Furthermore, rehealing with ~100% recovery of the compressive strength and electric conductivity was achieved under mild rehealing conditions, which is highly desired but has rarely been reported for electronic materials. The facile strategy for fabrication of rehealable monolithic polymer/GAs can open new possibilities for the sustainable development of composites with high electrical conductivity for various applications such as sensing, health monitoring, and movement detection.
The development of high-performance non-precious metal-based robust bifunctional electrocatalyst for both hydrogen evolution reaction (HER) and oxygen evolution reactions (OER) in alkaline media is essential for the electrochemical overall water splitting technologies. Herein, we demonstrate that the HER/OER performance of CoSe2 can be significantly enhanced by tuning the 3d-orbital electron filling degree through Mo doping. Both density functional theory (DFT) calculations and experimental results imply that the doping of Mo with higher proportion of the unoccupied d-orbital (Pun) could not only serve as the active center for water adsorption to enhance the water molecule activation, but also modulate the electronic structures of Co metal center leading to the optimized adsorption strength of *H. As expected, the obtained Mo-CoSe2 exhibits a remarkable bifunctional performance with overpotential of only 85 mV for HER and 245 mV for OER to achieve the current density of 10 mA/cm2 in alkaline media. This work will provide a valuable insight to design highly efficient bifunctional electrocatalyst towards HER and OER.
The cell surface membrane proteome is a class of proteins encoded by ~25% of all protein-coding genes in living organisms and plays a key role in mediating communication between the cells and their surrounding environment. However, most cell surface membrane proteins (CSMPs) are naturally expressed at very low levels compared with intracellular proteins. The difficulties in their purification with high specificity further hinder the understanding of their structure and function. In this study, we developed a new photolabeling probe to achieve efficient tagging and facile enrichment of the CSMPs. The probe is composed of a lipid tail for cell surface localization, a polyethylene glycol (PEG) spacer for increased water solubility, two 4-(N-maleimido)benzophenone (MBP) groups for UV-active tagging of the CSMPs, and a biotin tag for subsequent isolation. Application of this photolabeling probe resulted in the successful enrichment and identification of 3098 annotated CSMPs in HT22 cells with close to 70% selectivity. The proposed photolabeling probe and enrichment strategy were demonstrated to be a powerful method for deep cell surface proteome profiling, representing one of the largest groups of current drug targets.
Black phosphorus (BP) as an uprising two-dimensional material exhibits attractive potential in the field of electrocatalysis due to the inherent advantages of high carrier mobility and abundant lone pair electrons. However, the exposed active electrons compel BP to be deactivated by oxidative degradation. Herein, the electronic signature of acceptor-donor heterointerfacial interactions between BP and Co3O4 is realized via wet ball milling. The preferential migration of active electrons from BP to Co3O4 is achieved at the heterointerface since the Fermi level of BP is higher than that of Co3O4. Such relative energetic consideration promotes reasonable oxygen electrocatalytic active sites. Moreover, it significantly suppresses the oxidative degradation of BP. Consequently, the resulting Co3O4/BP heterojunction possesses superior oxygen bifunctional electrocatalytic activity than its parent catalysts. Most importantly, this work promotes an efficient route towards BP-based multifunctional catalysts.
The freshness of seafood can be judged by detecting the concentration of triethylamine (TEA). In this work, 2D CuO porous nanosheets (CuO PNs) were prepared by a graphene oxide template method and their particle sizes were regulated by changing the calcination temperature. Their structure, morphology and gas sensing performances were investigated by various characterization methods. The response (Rg/Ra) of the gas sensor based on CuO PNs calcined at 700 ℃ was as high as 440-100 ppm TEA at the operating temperature of 40 ℃. The detection limit was as low as 0.25 ppm. In addition, the gas sensor has good selectivity and stability. The excellent TEA sensitivity is mainly resulted from the appropriate particle size and loose porous framework. This work not only paves the way to explore the novel low temperature TEA gas sensors, but also provides deep insight on improving the structure and properties of gas sensitive materials by controlling the calcination temperature.
Photocatalytic recovery, a novel precious metal recycling technology, dedicates to solving the environmental and energy consumption problems caused by traditional technologies. The activation of molecular oxygen (O2) is one of the most critical steps in the whole process. Herein, we regulated the different adsorption intensity of oxygen on the surface by designing phosphate (PO43−) modified titanium oxide (TiO2). The results show that the adsorption of oxygen on the photocatalyst surface is gradually enhanced, which effectively improves the dissolution rate of precious metals. PO43− modification increased the photocatalytic dissolution rate of gold (Au) by 2.8 times. The photocatalytic activity of other precious metals dissolution (such as palladium (Pd), platinum (Pt), rhodium (Rh), ruthenium (Ru) and iridium (Ir)) was also significantly improved. It is applied to the recovery of precious metals from spent catalysts and electronic devices to significantly promote the recovery efficiency. This indicates the direction for designing more efficient photocatalysts for precious metal recovery.
In order to realize the sulfur and water resistance and facilitate the CO oxidation reactions, the effects of strain on the adsorption of CO, O2, SO2 and H2O molecules on Ni single-atom-catalyst supported by single-carbon-vacancy graphene (Ni-SG) have been studied based on first principles calculations. It shows that the compressive strain increases the adsorption energies of all above mentioned molecules on Ni-SG, where SO2 is adsorbed more strongly on Ni-SG than CO. However, in the presence of tensile strain, the adsorption energies decreases significantly when the molecules (O2 and SO2) obtain electrons from Ni-SG, while the adsorption energies just slightly decrease when the molecules (CO and H2O) lose electrons to Ni-SG, which finally achieves the preferential adsorption of CO and O2 molecules on Ni-SG by tensile strain. In addition, with tensile strain increasing to 10%, the rate-limited energy barrier along Eley-Rideal (ER) path monotonically increases from 0.77 eV to 0.98 eV, while the rate-limited energy barrier along Langmuir-Hinshelwood (LH) path monotonically decreases from 0.54 eV to 0.44 eV, indicating that the tensile strain can facilitate the LH mechanism while imped the ER mechanism on Ni-SG. The Hirshfeld charge and orbital levels of O2 and CO molecules are modulated by the tensile strain, which plays an important role for the decreasing of energy barriers for CO oxidation. Overall, the tensile strain can enhance the sulfur and water resistance of Ni-SG, as well as boost the CO oxidation reactions.