Latest ArticlesWe developed one-pot aqueous copolymerization of two dopamine prodrugs to prepare dual drugs-conjugated polydopamine nanoparticles (PDOXCBs), which integrated near infrared (NIR)-mediated photothermal effect with cocktail chemotherapy into one copolymer nanoparticle. Upon a mild NIR irradiation (808 nm, 1 W/cm2, 10 min), PDOXCBs gradually heated aqueous solution over 12.8–13.9 ℃, which accordingly enhanced in vitro dual doxorubicin (DOX) and chlorambucil (CB) drug-release with assistance of the other stimuli of pH 5.0 and 10 mmol/L D,L-dithiothreitol (DTT). The combination photothermal-cocktail chemotherapy (PTT-CCT) treatment based on PDOXCB27 plus NIR irradiation gave a highly lowered half maximal inhibitory concentration (IC50) of 2.23 μg/mL and a combination index of 0.36, displaying a superior synergistic effect between PTT and CCT in vitro.
A rhodium-catalyzed directing group promoted selective C–H olefination reaction of indolizines at the 8-position is reported. Di-olefination at 2,8-positions also achieved with silver hexafluoroantimonate as an additive under similar reaction conditions. Weakly coordinating groups, such as ketone, aldehyde, amide and ester, were used as directing groups. The ester group can be removed under acid conditions and therefore is used as a traceless directing group.
A practical synthesis of α-bromo/iodo/chloroketones from olefins under visible-light irradiation conditions has been developed. In the presence of PhI(OAc)2 as promoter and under ambient conditions, the reactions of styrenes and triiodomethane undergo the transformation smoothly to deliver the corresponding α-iodoketones without additional photocatalyst in good yields under sunlight irradiation. Meanwhile, the reactions of styrenes with tribromomethane and trichloromethane generate the desired α-bromoketones and α-chloroketones in high yields by using Ru(bpy)3Cl2 as a photocatalyst under blue LED (450–455 nm) irradiation.
AA005 (1), a potent anticancer mimicking molecule of natural Annonaceous acetogenin, features a central C2-symmetric triglycol moiety and three stereogenic centers. To support ongoing animal studies, a scalable 10-step synthesis of AA005 (1) has been studied, optimized and accomplished in this work, starting from commercially available economic materials ethylene glycol and (R)-epichlorohydrin. A regio- and stereo-controlled BF3·Et2O-promoted epoxide opening of (R)-epichlorohydrin with ethylene glycol was investigated, optimized and successfully applied to the scalable preparation of the crucial fragment 6a with C2-symmetry. Further successive epoxide openings elaborated both two side chains and the whole skeleton with proper nucleophiles and electrophiles. Comparison and optimization of the reaction sequences finally led to completion of a new multi-gram synthesis of AA005 (1) with satisfactory enantiomeric and diastereomeric purity.
Low-cost silicon microparticles (SiMP), as a substitute for nanostructured silicon, easily suffer from cracks and fractured during the electrochemical cycle. A novel n-type conductive polymer binder with excellent electronic and ionic conductivities as well as good adhesion, has been successfully designed and applied for high-performance SiMP anodes in lithium-ion batteries to address this problem. Its unique features are attributed to the strong electron-withdrawing oxadiazole ring structure with sulfonate polar groups. The combination of rigid and flexible components in the polymer ensures its good mechanical strength and ductility, which is beneficial to suppress the expansion and contraction of SiMP s during the charge/discharge process. By fine-tuning the monomer ratio, the conjugation and sulfonation degrees of the polymer can be precisely controlled to regulate its ionic and electronic conductivities, which has been systematically analyzed with the help of an electrochemical test method, filling in the gap on the conductivity measurement of the polymer in the doping state. The experimental results indicate that the cell with the developed n-type polymer binder and SiMP (~0.5 μm) anodes achieves much better cycling performance than traditional non-conductive binders. It has been considered that the initial capacity of the SiMP anode is controlled by the synergetic effect of ionic and electronic conductivity of the binder, and the capacity retention mainly depends on its electronic conductivity when the ionic conductivity is sufficient. It is worth noting that the fundamental research of this work is also applicable to other battery systems using conductive polymers in order to achieve high energy density, broadening their practical applications.
A Si-substituted rhodamine based water-soluble fluorescent probe bearing a tetrathia-azacrown was designed for fluorescence imaging of Cu+ with substantial affinity and selectivity. In physiological condition, the developed probe with outstanding water-solubility exhibits ultrahigh sensitivity to Cu+, ensuring the reliable fluorescence imaging in vivo.
g-C3N4 have been widely used in the fields of photocatalytic hydrogen production, photocatalytic degradation of dyes and oxidative degradation of toxic gases due to their excellent performance. It has attracted extensive attention in recent years due to its highly efficient photocatalytic capacity of hydrogen generation, water oxidation, carbon dioxide reduction and degradation of organic pollutants. Because of the abundant carbon and nitrogen composition of the earth, large-scale production and industrial applications of this material are possible. The modification of this material makes its performance more excellent so that this new material can obtain a steady stream of vitality. These outstanding works have become important materials and milestones on the road to mankind's photocatalytic hydrogen production. This review will begin with the basic idea of designing, synthesizing and improving g-C3N4 based photocatalytic materials, and introduce the latest development of g-C3N4 photocatalysts in hydrogen production from four aspects of controlling the carbon/nitrogen ratio, morphology, element doping and heterojunction structure of g-C3N4 materials.
Selection of aptamers with high affinity and good specificity requires multiple rounds of alternating steps of separation and PCR amplification. Herein, we proposed a novel high-efficiency aptamers picking strategy: One-round pressure controllable selection (OPCS). OPCS integrates four types of screening superiority, high-efficiency separation, one-round selection and PCR amplification, synchronous negative selection and targets competition. The controllable screening pressure can be achieved through two approaches, balanced competition by the regulation of protein concentration, and dominant competition by introducing a predatory protein with high concentration. In OPCS process, two proteins were co-incubated with one ssDNA library, and each protein bound its favorable sequences specifically and formed protein-ssDNA complex respectively. Meanwhile, one protein could supply/suffer the picking pressure of affinity and specificity to/from another, which eliminated weakly bound or unbound sequences for each other. Two complexes could be separated and collected conveniently, and aptamers for two proteins obtained synchronously with high affinity and good specificity. This strategy not only provides a more effective way for aptamers selection, but shows great potential in other ligands or drugs selection.
The metabolic disorder of glucose in human body will cause diseases such as diabetes and hyperglycemia. Hence the determination of glucose content is very important in clinic diagnosing. In recent years, researchers have proposed various non-invasive wearable sensors for rapid and real-time glucose monitoring from human body fluids. Unlike those reviews which discussed performances, detection environments or substrates of the wearable glucose sensor, this review focuses on the sensing nanomaterials since they are the key elements of most wearable glucose sensors. The sensing nanomaterials such as carbon, metals, and conductive polymers are summarized in detail. And also the structural characteristics of different sensing nanomaterials and the corresponding wearable glucose sensors are highlighted. Finally, we prospect the future development requirements of sensing nanomaterials for wearable glucose sensors. This review would give some insights to the further development of wearable glucose sensors and the modern medical treatment.
An intramolecular dehydrogenative homo- and hetero-coupling of phenols has been successfully developed for quick preparation of enantiopure axial diphenols under mild Cu(Ⅱ)-mediated conditions, using ((4S, 5S)-2,2-dimethyl-1,3-dioxolane-4,5-diyl)dimethanol as the chiral auxiliary. The commercially available (R)-α-methylbenzylamine was identified as the best amine ligand for Cu(Ⅱ) in the reactions. A variety of homo/hetero bis-dihydroxylbenzoate substrates were examined, affording the corresponding axially chiral diphenols with satisfactory to excellent diastereomeric ratios, and a representative scalable preparation was also attempted. A formal synthesis of natural product (+)-deoxyschizandrin has been achieved in this work using one axially chiral diphenol as the synthetic intermediate.