Latest ArticlesGlutathione depletion provides a promising strategy for the design of non-platinum anticancer drugs. Here we report a series of electrophilic (salen)osmium(Ⅵ) nitrides that react with glutathione to generate (salen)osmium(Ⅲ) ammine compounds. In vitro studies indicate that these osmium(Ⅵ) nitrides show comparable cytotoxicity to cisplatin against various carcinoma. Mechanistic studies with the representative compound [OsⅥ(N)(LH)(OH2)](PF6) (1, LH = N,N′-bis(salicylidene)-o-cyclohexyldiamine dianion) suggest that 1 induces glutathione depletion, reactive oxygen species generation, endoplasmic reticulum stress, and in turn triggers death receptor-mediated apoptosis and autophagy in lung cancer cells. In vivo evaluations show that 1 can inhibit tumor xenograft growth effectively with no body weight drop.
Chemical upcycling of end-of-life poly(lactide) plastics to lactide, lactate ester and new poly(lactide) has been achieved by using magnesium bis[bis(trimethylsilyl)amide] [Mg(HMDS)2] as promoter. Mg(HMDS)2 showed high efficiency in L-lactide polymerization and poly(lactide) depolymerization. Mg(HMDS)2/Ph2CHOH catalytic system displayed high ring-opening selectivity and the characteristic of immortal polymerization. Taking advantage of transesterification, depolymerizations of end-of-life poly(lactide) plastics to lactate ester (polymer to value-added chemicals) and lactide (polymer to monomer) were achieved with high yields. Besides, a new "depolymerization-repolymerization" strategy was proposed to directly transform poly(lactide) into new poly(lactide). This work provides a theoretical basis for the design of polymerization and depolymerization catalysts and promotes the development of degradable polymers.
Nonfullerene acceptors (NFAs), which usually possess symmetric skeletons, have drawn great attention in recent years due to their pronounced advantages over the fullerene counterparts. Moreover, breaking the symmetry of NFAs could fine tune the molecular dipole, solubility, energy level, intermolecular interaction, molecular packing, crystallinity, etc., and give rise to improved photovoltaic performance. Currently, there are three main strategies for the design of asymmetric NFAs. This review highlights the recent advances of high-performance asymmetric NFAs and briefly outlooks the materials exploration for the future.
Simultaneous acquisition of fluorescence property and refractive index using a single surface plasmon coupled emission (SPCE) measurement has been achieved, thus achieving synchronicity in real time. The SPCE sensor was employed for monitoring the adsorption of volatile organic compounds (VOCs) by dye-encapsulated metal-organic frameworks (Dye@MOFs). Refractive index can reveal surface molecular adsorption and the fluorescence with information on refractive index can provide a comprehensive analysis of the adsorption events of VOCs on the interface. Meantime, the signal intensity can be amplified by combining the responses caused by changes in refractive index and the fluorescence property in parallel. This all-in-one method opens up a route to monitoring multiple processes simultaneously occurring on the interface.
Titanium dioxide (TiO2) has been widely investigated as a candidate for anode materials of sodium-ion batteries (SIBs) due to its low cost and high abundance. However, the intrinsic sluggish ion/electron transfer rate hinders its practical applications for high energy density storage devices. In contrast, antimony (Sb) shows high specific theoretical capacity (660 mAh/g) as well as excellent electron conductivity, but the large volume variation upon cycling usually leads to severe capacity fading. Herein, with the objective of achieving high-performance sodium storage anode materials, TiO2@C-Sb nanotablets with a small amount of Sb content (6.4 wt%) are developed through calcination Ti-metal–organic framework (MIL-125) derived TiO2@C/SbCl3 mixture under reductive atmosphere. Benefitting from the synergetic effect of well-dispersed Sb nanoparticles as well as robust porous TiO2@C substrate, the TiO2@C-Sb shows enhanced electron/ion transfer rate and predominantly pseudocapacitive sodium storage behavior, delivering a reversible capacity of 219 mAh/g at 0.5 A/g even after 1000 cycles. More significantly, this method may be commonly used to incorporate other alloy-based high-theoretical materials into MIL-125-derived TiO2@C, which is promising for developing high-energy-density TiO2-based energy storage devices.
Lignin and its derivatives hold great potential in developing high performance porous carbon materials for supercapacitors due to the versatile features of high carbon content, abundant multifunctional groups, low cost, and environmental benefits. Unfortunately, their derived porous carbon generally has the features of unfavorable microporous-dominated morphologies and low specific surface area (SSA) attributed from the highly-branched structure of lignin, which are hardly suitable for the supercapacitors with ionic liquid (IL) electrolyte, leading to poor energy density and rate capability. Herein, porous carbon materials with desirable mesoporous contributions from sodium lignosulphonate are designed via a facile template method. Such rich mesoporisity carbon materials not only possess with three-dimensional interconnected network, large SSA, as well as favorable pore size distribution for accelerated ion and electron mass transfer, but also feature low heteroatom content for high electrochemical stability. Consequently, the optimal electrode exhibits a high capacitance of 166 F/g at 0.5 A/g, superior rate performance (59 Wh/kg at 59 kW/kg), as well as impressive cycle life with good capacitance retention of 93.1% in EMIBF4 electrolytes. The present work opens a new avenue to design porous carbon materials with high mesopore properties from lignin for effective compatibility with IL electrolyte in high-performance supercapacitors.
Iron-chromium redox flow batteries (ICRFBs) possess advantages of high safety, long cycle time, and low-cost. Increasing Cr3+/Cr2+ reaction activity is suggested as one of the most promising strategies to improve the performance and prolong the lifetime of ICRFBs. To improve the slow reaction kinetics of the negative electrode, a type of defected carbon cloth with Bismuth (Bi) catalyst introduction is prepared by defect engineering method and electrochemical deposition, which provided defect sites and active sites to catalyze the redox couple's reaction of ICRFBs. Furthermore, this modified carbon cloth adsorbs Cr(Ⅲ) hydrate more easily, which has a more stable structure and can significantly improve the performance of ICRFBs. Both experimental analysis and theoretical calculation indicated that the modified electrode has excellent electrocatalytic ability, which can enhance the reaction rate of Cr3+/Cr2+, improve capacity retention and stabilize cycling performance. The capacity degradation rate of an ICRFB single cell with the modified electrodes is just 0.23% per cycle at a current density of 140 mA/cm2. Additionally, the energy efficiency (EE) remains around 83%, which is 8.45% higher than that of the pristine electrode assembled battery under 60 cycles. This work supplies a simple method to obtain a high-performance electrode material for ICRFBs and makes it a practical solution to promote ICFRBs large-scale commercialization process.
The effective removal and selective detection of explosive and toxic pollutant trinitrophenol (TNP) is an attractive but challenging field. Herein, a double-cavity nor-seco-cucurbit[10]uril (ns-Q[10])-based supramolecular assembly 8-HQ@ns-Q[10] was fabricated and its structure was characterized by X-ray single crystal diffraction. In this assembly, the stoichiometric ratio of ns-Q[10] and 8-hydroxyquinoline (8-HQ) is 1:2, which is also attributed to the special double-cavity structure of ns-Q[10]. The luminescence sensing experiments showed that 8-HQ@ns-Q[10] can be used as a good fluorescence-enhanced sensing material (enhanced 27-fold) for the rapid detection of explosives and the aqueous contaminant TNP, with a limit of detection (LOD) of 2.07 × 10−5 mol/L, without interference from other phenolic compounds. Furthermore, TNP can be efficiently removed in the presence of assembly 8-HQ@ns-Q[10], and the removal efficiency is more than 89%. Therefore, the supramolecular assembly 8-HQ@ns-Q[10], as a fluorescence-enhanced luminescence sensor and adsorption material, has rich research value and potential application prospect when applied to the detection and removal of TNP in aqueous environment.
DNAzyme machines play critical roles in the fields of cell imaging, disease diagnosis, and cancer therapy. However, the applications of DNAzyme machines are limited by the nucleases-induced degradation, non-specific binding of proteins, and insufficient provision of cofactors. Herein, protected DNAzyme machines with different cofactor designs (referred to as ProDs) were nanoengineered by the construction of multifunctional metal-phenolic nanoshells to deactivate the interferential proteins, including nucleases and non-specific binding proteins. Moreover, the nanoshells not only facilitate the cellular internalization of ProDs but provide specific metal ions acting as cofactors of the designed DNAzymes. Cellular imaging results demonstrated that ProDs could effectively and simultaneously monitor multiple tumor-related microRNAs in living cells. This facile and rapid strategy that encapsulates DNAzyme machines into the protective metal-phenolic nanoshells is anticipated to extend to a wide range of functional nucleic acids-based biomedical applications.
Mitochondria are essential for eukaryotic life as powerhouses for energy metabolism. Excessive mitochondrial hyperthermia and reactive oxygen species (ROS) production have been associated with aging, cancer, neurodegenerative diseases, and other disorders. Uncoupling protein 2 (UCP2) is the effector responsible for regulating cellular thermogenesis and ROS production via dissipating protons in an electrochemical gradient. A UCP2 inhibitor named genipin (GNP) is being researched for its effect on mitochondrial temperature, but little is known about its mechanisms. This study developed several molecular probes to explore the interactions between GNP and UCP2. The result indicated that the hemiacetal structure in GNP could selectively react with the ɛ-amine of lysine on the UCP2 proton leakage channel through ring-opening condensation at the mitochondrial, cellular, and animal levels. A notable feature of the reaction is its temperature sensitivity and ability to conjugate with UCP2 at high fever as lysine-specific covalent inhibitors that prevent mitochondrial thermogenesis. The result not only clarifies the existence of an antipyretic properties of GNP via its irreversible coupling to UCP2, but also reveals a bioorthogonal reaction of hemiacetal iridoid aglycone for selectively binding with the ɛ-amine of lysine on proteins.