Monthly ,Founded in 1964 Resume Publication in 1980 Editor-in-Chief:YU Jihong ISSN 0251-0790 CN 22-1131/O6
Exosome proteomic analysis has important value in screening biomarkers for major diseases, discovering drug targets, and studying functional mechanisms. Exosome and protein are widely recognized as research objects that are highly susceptible to temperature changes. However, previous reports have often attributed the differences in exosome proteomic analysis results based on different enrichment strategies directly to the differences in enrichment selectivity and efficiency of different enrichment methods. There has not been sufficient research and discussion on the impact of temperature changes during the enrichment process of exosome on the results of exosome proteomic analysis. To investigate the effect of sample processing temperature on the results of exosome proteomics analysis, this study treated exosome samples at six temperature conditions of 4, 25, 37, 45, 60, and 90 ℃ for 1 h. Subsequently, the morphology characteristics, particle size distribution and concentration, changes in characteristic protein characterization content, and proteomic data of the samples were systematically analyzed. The results showed that there were no significant differences in morphology and particle size among exosomes treated at different temperatures, But as the temperature increases, the concentration of exosome particles significantly decreases. When the temperature exceeds 45 ℃, the characterization content of the exosome marker protein TSG101 significantly decreases, while conversely, the characterization content of the exosome characteristic membrane protein CD9 significantly increases. The results of quantitative proteomics analysis further indicate that the proteomic data of exosome samples treated at 4, 25 and 37 ℃ have good comparability, while samples treated at 45 ℃ and above show significant differences in 48 proteins. In summary, when conducting exosomal proteomic analysis, the potential impact of temperature changes on measurement results should be fully considered to ensure the reliability, reproducibility, and comparability of the data.
A fluorescent probe of poly(thymidine)-copper nanoclusters/aptamer-gold nanoparticles(poly(T)-CuNCs/aptamer-AuNPs) was constructed for highly sensitive sensing detection of microcystin-LR(MC-LR) using DNA template method. Three DNA nucleotides were designed, including MC-LR aptamer, and two poly(thymidine) ssDNA(poly(T) S1 and poly(T) S2). Using poly(T) S1 and poly(T) S2 as templates, poly(T) S1-CuNCs and poly(T) S2-CuNCs with pink fluorescence were synthesized by reducting Cu2+ with ascorbic acid(AA). Aptamer labeled with thiol groups at two both ends were linked with AuNPs through Au—S bonds to form AuNPs-aptamer- AuNPs bioconjugates. AuNPs-aptamer-AuNPs hybridized with poly(T)-CuNCs to form dsDNA-CuNCs. Fluorescence resonance energy transfer(FRET) occurred between CuNCs and AuNPs in the dsDNA-CuNCs structure, leading to fluorescence quenching of dsDNA-CuNCs. In the presence of target MC-LR, MC-LR specifically bonded with aptamer in dsDNA-CuNCs, resulting in the dissociation of dsDNA structure. The poly(T)-CuNCs were released into the solution, restoring the system's fluorescence. An "off-on" type of fluorescent probe was constructed for the detection of MC-LR. The linear range for MC-LR detection is 1 ng/L—500 µg/L, with a detection limit of 0.3 ng/L (S/N=3). The proposed fluorescent aptamer probe possesses the advantages of simple preparation, high selectivity, and can be applied for quantitative detection and analysis of MC-LR in real water samples.
A glycosylated electrochemical sensor for rapid identification and detection of breast cancer PD-L1 positive exosomes was developed. First, glycosyl-imprinted polymers(GIP) were prepared by electropolymerization using glyco-Galβ1-4GlcNAcβ1-3Galβ1-4GlcNAcβ1-3Gal overexpressed by breast cancer positive exosome glycoprotein PD-L1 as template molecules and 3-aminophenylboronic acid as functional monomers. After elution and removal of template molecules, an imprinted membrane that can specifically recognize PD-L1 positive exosomes was obtained. Potassium ferricyanide was used as a probe to measure the DPV current value of the GIP electrode. Exosomes were cleaved with RIPA to deduct free protein interference, and the change in current value(ΔI) was recorded. ΔI decreased with the increase of the concentration of readsorbed PD-L1-positive exosomes, and was linearly positively related to the logarithmic value of the concentration. The detection range was 2.36×102—1.18×107 particles/mL, and the detection limit was 93 particles/mL. The method has been used to detect breast cancer PD-L1-positive exosomes in clinical samples, and its spiked recoveries were 93.82%—105.32%. The sensor could be used to screen breast cancer in clinical samples by the difference in glycosylation degree.
The quantification of ethylene can be achieved through the change of fluorescence signal, but there are few reports about the real-time monitoring of ethylene levels in plant tissues. Developing environmentally friendly and biocompatible chemical-based fluorescent probes is one of the ways to achieve plant tissue imaging. This article uses casein as a carrier to create a water-soluble fluorescent probe(C-E-P) by encapsulating a fluorescent probe(P3) that combines the first-generation Grubbs catalyst with 6-methoxy-2-naphthylene in a hydrophobic pocket. The synthesis of probe P3 was confirmed through various structural characterization methods. Performance tests demonstrated that P3 exhibited a strong linear relationship with ethylene, rapid reaction time, and high selectivity. The C-E-P, created by encapsulating P3 with casein, facilitated fluorescence imaging of ethylene release from apple, bitter water rose, and aloe tissues. This approach allowed for observing changes in ethylene release between different plant tissues over time. Additionally, it was employed to monitor ethylene variations in the tissues of white ripe tomatoes during ripening, revealing that the peak ethylene release from the seeds occurs before that from the pericarp. The C-E-P developed in this study can effectively capture ethylene release information in plant tissues, providing an effective tool for fruit ripening and plant health monitoring in agricultural production.
Fiber-based organic electrochemical transistors have broad application prospects in the fields of wearable electronic devices and biosensors due to the advantages of being flexible and wearable, low working voltage, high sensitivity, and good biocompatibility. In this study, cotton fiber was used as the raw material for electrodes, and graphene(Gr) and poly(3,4-ethylenedioxythiophene)-sodium polystyrene sulfonate(PEDOT∶PSS) were used to modify the fiber surface to form a layer of PEDOT∶PSS/Gr film on the fiber surface. The resistance of the poly(3,4-ethylenedioxythiophene)-sodium polystyrene sulfonate/graphene/fiber(PEDOT∶PSS/Gr/fiber) was as low as 60 Ω/cm. An organic electrochemical transistor device with stable output performance and high sensitivity was constructed by PEDOT∶PSS/Gr/fiber, and showed good linear response to glucose detection in the range of 1 pmol/L—10 μmol/L, with a detection limitation of 1 pmol/L. In addition, it is demonstrated that the sensor can resist interference from uric acid, ascorbic acid, and common metal ions(K+, Na+, Mg2+), which are common interferences in body fluids. The recovery rate was 87.2%—110% when used to detect saliva samples. This study can provide some technical support for non-invasive detection of blood glucose in diabetes.
An aromatic acridine derivative with photoremovable protecting group(PPG) properties was designed and synthesized. The host-guest recognition process between this guest molecule and cucurbit[n]uril(CB[n], n=7, 8, 10) was investigated, along with the effects of host-guest interaction on the photolysis of the guest in aqueous-phase using nuclear magnetic resonance(NMR), ultraviolet visible(UV-Vis) and fluorescence spectroscopies. The results showed that CB[7] formed a 1׃1 host-guest inclusion complex, while CB[8] formed both 1׃1 and 1׃2 complexes with the guest. Similarly, CB[10] exhibited a 1׃2 binding mode. Furthermore, CB[7] was found to inhibit the photolysis, whereas CB[8] significantly enhanced the photolysis rate of the guest. This study highlights how subtle variations in CB[n] cavity size influence the photolysis reaction, offering insights into the design of CB[n]-based nanoreactor- mediated supramolecular systems for aqueous-phase photolysis of PPG molecules.
In order to obtain novel antibacterial compounds, using the principle of pharmacophore assembly, twenty-four novel thioxime amide derivatives containing thiopeptide were designed and synthesized by combining active fragments of amino thiazole, oxime and thiopeptides, and confirmed by means of nuclear magnetic resonance hydrogen spectroscopy(1H NMR), nuclear magnetic resonance carbon spectroscopy(13C NMR) and elemental analysis. The antibacterial activities test results showed that these derivatives have significant activity against Gram positive bacteria. the minimum inhibitory concentration(MIC) values of compound 5u against S. aureus and methicillin-resistant S. aureus(MRSA) were 0.25 μg/mL and 2 μg/mL respectively, the MIC values of 5v against S. aureus and MRSA were 0.5 μg/mL and 2 μg/mL, respectively. Its anti-S. aureus activity was superior to that of the control drug oxacillin(MIC=0.5 μg/mL) or relatively, and its anti-MRSA activity was significantly better than that of the control drug(MIC>128 μg/mL), which will be further developed as novel candidates for antibacterial drugs.
Based on the density functional theory(DFT), the Minnesota functional M06-2X method was employed to study the ring-opening reaction mechanism of (2S,3S)-2-phenyl-1-[(S)-1-phenylethyl]azetidin-3-amine reacting with phenylisothiocyanate or phenylisocyanate. The amine reacting with phenylisothiocyanate generates an interme- diate, which then undergoes proton transfer. Subsequently, the sulfur atom conducts a nucleophilic attack on the C2 position of the four-membered ring to give dihydrothiazole after isomerization from a five-membered ring. The amine reacting with phenylisocyanate forms urea. Protic acid or copper trifluoromethanesulfonate is required when the four-membered ring of the urea undergoes a ring-opening reaction.
On the basis of commonly used triphenylamine donor units and dibenzo [a, c] phenazine acceptor units, two red light thermally activated delayed fluorescence(TADF) materials TPA-DSP and SPTPA-DSP were designed and synthesized by the steric hindrance effect of spirofluorene group. The spirofluorene group, known for its large steric hindrance, increases the rigidity of the molecule, avoids tight packing between emissive cores and effectively reduces non-radiative transition energy loss, which is crucial for improving device performance. When doping in 4,4′-bis(N-carbazolyl)-1,1′-biphenyl(CBP) as organic light emitting layer, TPA-DSP and SPTPA-DSP exhibited excellent performance in organic light-emitting diodes(OLEDs). Both materials emitted red light, with TPA-DSP achieving a maximum external quantum efficiency(EQE) of 17.8% at 580 nm with a 7% doping concentration(mass fraction). SPTPA-DSP, featuring multiple spirofluorene groups, demonstrated superior device performance, achieving a maximum EQE of 19.3% at 580 nm with a 7% doping concentration(mass fraction). The maximum luminance of TPA-DSP and SPTPA-DSP reached 11800 and 12650 cd/m2, the maximum current efficiency(CE) both reached 40.0 cd/A, and the maximum power efficiency(PE) reached 44.3 and 47.2 lm/W, respectively. Notably, SPTPA-DSP, featuring multiple spirofluorene groups, demonstrated superior device performance due to its greater steric hindrance. Our findings underscore the potential of the spirofluorene group to enhance the performance of TADF materials through steric hindrance effects, which not only contributes to understanding the effect of steric hindrance in TADF but also paves the way for further advancements and applications.
In the electrochemical carbon dioxide reduction reaction(ECO₂RR), catalytic materials face the challenge of complex practical application conditions, especially in terms of poisoning resistance. In this study, commercial multi-walled carbon nanotubes(MWCNT) were used to prepare defects rich in graphitic carbon materials through nitrogen doping and removal methods. The morphology, crystal structure, elemental composition, and defect degree of the catalysts were analyzed and characterized by transmission electron microscopy(TEM), aberration- corrected scanning transmission electron microscopy(AC STEM), X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS), and Raman spectrometer. Based on the flow cell testing system, the results showed that the activity of defective carbon nanotubes is much higher than that of untreated carbon nanotubes, and the catalytic performance improves with the increase of defect degree. Among them, MWCNT-N-800 with the highest defect degree can achieve excellent electrochemical activity for carbon dioxide reduction to carbon monoxide over a broad potential range, with a maximum carbon monoxide Faraday efficiency of more than 99% and a current density of more than 200 mA/cm2. Furthermore, under the simulated flue gas conditions containing poisoning substances, the Faradaic efficiency of carbon monoxide for MWCNT-N-800 still remained above 96%, showing good poisoning resistance. This study provides ideas for the development of efficient and poison-resistant non-metallic ECO₂RR catalysts.
The reaction interface microenvironment is an important factor that affects photocatalytic reaction performance. In this study, a highly efficient triphase interface reaction system was constructed by regulating the surface wettability for photocatalytic oxidation of organic compounds. Titanium dioxide(TiO2) nanoparticle is used as a model photocatalyst, polydimethylsiloxane(PDMS) is grafted onto the surface to enhance the hydrophobicity. The results show that the presence of hydrophobic a PDMS layer enables the formation of a gas-liquid-solid triphase coexisting microenvironment at the reaction interface, which increases the interfacial oxygen(O2) concentration. Meanwhile, the hydrophobic surface layer enhances the adsorption capability of organic molecule. Such synergistic effect promotes the generation of superoxide radicals(•2-) and hydroxyl radicals(•OH) and enhances the photocatalytic oxidation reaction. This work provides a novel approach to design and construction of efficient catalytic reaction systems.
As one of the energy-intensive processes, the production of ethylene glycol with high selectivity from ethylene oxide under low hydration ratios is a challenge in the industry. In this study, a series of porous poly(ionic liquid)s with high specific surface area and macroporous structure were synthesized through free radical copoly- merization of rigid ionic liquids and organic base monomers. The structure, microscopic morphology, and thermal stability of the poly(ionic liquid)s were characterized by magic angle spinning nuclear magnetic resonance(MAS NMR) spectroscopy, Fourier transform infrared(FTIR) spectroscopy, scanning electron microscopy(SEM), N2 physical adsorption-desorption, and thermogravimetric analysis(TGA). These poly(ionic liquid)s have a specific surface area ranging from 100.9 m²/g to 374.7 m²/g, a pore volume ranging from 0.41 cm³/g to 0.86 cm³/g, with active sites uniformly distributed within the porous structure. Porous poly(ionic liquid)s possessing both the active centers of ionic liquids and organic bases could synergistically catalyze the CO2-promoted hydration of ethylene oxide. Under a low hydration ratio of 1.5∶1, high yield(96.5%) and selectivity(96.5%) of ethylene glycol are achieved, which are comparable to the corresponding homogeneous catalysts. The CO2-promoted catalysis alters the pathway of hydration reaction, significantly reducing the hydration ratio and improving the selectivity of ethylene glycol. In addition, the catalyst has good substrate applicability and recyclability, and it also shows good catalytic performance under the flue gas atmosphere.
MoS2 has been expected as a potential material in photocatalytic water splitting, and the efficiency of hydrogen production can be improved by loading the plasmonic Ag nanoparticles. In this work, the influence of Ag nanoparticles and its temperature rise from the thermoplasmonics effect on the interfacial properties of MoS2-H2O was investigated. Based on the fabrication of the model of MoS2 loaded with Ag clusters, the interfacial properties such as the interfacial water density, the Helmholtz layer width, the surface electrostatic potential and the water diffusion coefficient were calculated by molecular dynamics at 298—368 K, and the interfacial electron transfer, the adsorption energy, and the desorption time of water molecule were also analyzed by combined with the calculation of density functional theory. The results show that the Helmholtz layer width increases and the surface electrostatic potential decreases when loading Ag nanoparticles on the MoS2 surface. The adsorption energy of water molecules enhances due to the interaction between Ag nanoparticles and water molecules on MoS2 surface, leading to a relative increase in the delamination range of water molecules. With the increase of temperature, the adsorbed water molecules on the surface of Ag/MoS2 decreases, and the delamination range of water molecules as well as their diffusion coefficient increases. Considering the change in the surface electrostatic potential, the desorption time of water molecules with loading Ag nanoparticles and the temperature rise, the desirable temperature for the interface reaction could be about 328 K.
Simultaneously considering both high fidelity and low computational cost presents a significant challenge in modeling the pyrolysis and oxidation of fuels. In this work, a comprehensive kinetic model for the pyrolysis of n-alkanes covering n-heptane, n-decane, and n-dodecane had been developed based on the minimized reaction network(MRN) method. The total mechanism consists of 32 species and 58 reactions, which are validated against pyrolysis experimental data and mechanisms of multi-sizes in numerical simulations. In the pressure range of 0.02—5.00 MPa and the temperature range of 573—1732 K, the ability of this mechanism to predict the pyrolysis conversion and gas production of n-alkanes with temperature, pressure, and time variations is comparable to that of the detailed mechanism. Especially at high pressures, the sub-mechanisms for n-decane and n-dodecane exhibit higher predictive precision regarding both fuel conversion rates and the profiles of alkenes and acetylene, which makes them suitable for engineering numerical simulations of fuel pyrolysis and heat transfer. The pyrolysis mechanism can also be coupled with oxidation reactions to construct combustion mechanisms.
In this paper, 5,10,15,20-tetraphenylporphyrin(TPP) complexes of transition metals(MTPP, M=Co, Cu, Mn, Ni, Fe) were prepared and the metalloporphyrin/multi-walled carbon nanotubes composites(MTPP/ MWCNTs) for electrocatalytic hydrogen evolution reaction(HER) were fabricated by non-covalent interactions. The results showed that the composite CoTPP/MWCNTs exhibited the best electrocatalytic HER performance when the loading amount(mass fraction) of metalloporphyrin was 10%. The ultraviolet-visible diffuse reflectance spectroscopy(UV-Vis DRS) and X-ray photoelectron spectroscopy(XPS) results showed that there are strong π-π interactions between the metalloporphyrin and the multi-walled carbon nanotubes. The catalytic activities of MTPP/MWCNTs follows the order of Co>Cu>Mn>Ni>Fe. Among them, the CoTPP/MWCNTs shows an overpotential of 631 mV at the current density of 10 mA/cm2, the smallest Tafel slope(161.3 mV/dec) and charge transfer resistance(10.3 Ω), suggesting the utilization of the non-covalent combination of metalloporphyrin with multi-walled carbon nanotubes is an effective way to construct composite electrocatalysts.
Reversible-deactivation radical polymerization(RDRP) regulated by single-molecule alkoxyamine features a simple process, produces polymers with light color and minimal odor, and is free of metal ion impurities. However, the design and synthesis of alkoxyamines capable of regulating the polymerization of methacrylate monomers remains a challenging task. In this paper, an innovative type of alkoxyamine{3-[(2-cyanopropan-2-yl)oxy](isopropyl)amino}- 2,2-dimethyl-3-phenylpropanenitrile(CPDMN) was synthesized via Schiff base reduction, potassium persulfate complex oxidation and radical coupling, and then the controlled polymerization behavior of methyl methacrylate(MMA) mediated by CPDMN was investigated. The experimental results demonstrate that the monomer conversion rate increases linearly with polymerization time, while the polymer molecular weight grows with prolonged reaction duration. Gel permeation chromatography traces exhibit symmetrical peaks without significant tailing, indicating characteristic features of controlled/living radical polymerization. Subsequent re-initiation experiments using poly(methyl methacrylate) macroinitiator(PMMA-ONR) with MMA, styrene(St), and ethyl methacrylate(EMA) further confirm the effective retention of alkoxyamine end-groups in the resulting polymers. Finally, the regulation performance of CPDMN on MMA in the presence of oxygen was investigated, achieving a monomer conversion rate of 91.2% and a PMMA molecular weight distribution of less than 1.5, which demonstrates that CPDMN can control the polymerization of MMA with oxygen tolerance. The as-synthesized CPDMN extends the range of monomers applicable to nitroxide-mediated polymerization(NMP), demonstrating promising potential for the synthesis of functional polymeric materials.
The effects of different phosphorus-nitrogen compounds on the polymerization of 1,3-butadiene and isoprene catalyzed by iron(III) acetylacetonate/aluminium alkyl[Fe(acac)3/AlR3] were investigated. The results show that the use of isocyanoimino-triphenylphosphorane(IITP) as an electron donor can synthesize syndiotactic 1,2-polybutadiene(PBd) and 3,4-polyisoprene(PIp) with high activity in hexane, and the highest catalytic activity achieve 1.52×106 gPBd/molFe and 1.47×106 gPIp/molFe. The obtained polybutadiene displays a low melting point (Tm, 64.0—115 ℃), and the molar fraction of 1,2-unit can reach up to 80.2%. The molar fraction of 3,4-unit of polyisoprene is between 48.8%—52.4%, and the temperature of glass transition(Tg) is kept from -18.5 ℃ to -15.8 ℃. The unimodal distribution high-temperature gel permeation chromatography(HTGPC) curve indicates that the catalytic system has a single active center. Moreover, the quasi living polymerization characteristics of the catalytic system are verified through kinetics and seeding polymerization experiments of isoprene.
The self-assembly behaviors of cyclic A4B6C6 triblock copolymers in block A selective solvents were studied using Monte Carlo simulation method, and compared with the self-assembly behaviors of linear A4B6C6 and A4C6B6 triblock copolymers. The simulation results show that by adjusting the hydrophobicity of block C and the hydrophobicity difference between blocks B and C, the cyclic A4B6C6 triblock copolymer can self-assemble into various polymer micelles with different morphologies, such as segmented worms, segmented layers, and segmented vesicles with single or multiple aqueous cavities. It is worth noting that due to the unique topological structure of cyclic block copolymers, even if the hydrophobicity difference between blocks B and C exists, the hydrophobic cores of these micelles tend to form a segmented structure with alternating blocks B and C. Compared to the cyclic system, the self-assembly behaviors of linear A4B6C6 and A4C6B6 triblock copolymers under the same parameter conditions are relatively simple, and most of them form spherical micelles. The arrangement of blocks B and C in the hydrophobic core of spherical micelles strongly depends on the chain structure of the linear block copolymers. The above simulation results are beneficial for understanding the mechanism of the influence of chain structure on the morphology of block copolymer micelles, and provide necessary theoretical basis for the preparation of polymer micelles with specific hydrophobic core structures.