A facile
method was developed to fabricate fibrous membranes of niobium-doped
titania-supported platinum catalysts (Pt@Nb-TiO2) by a
two-step approach. The process started with generating niobium-doped
titania (Nb-TiO2) fibrous membranes by electrospinning,
followed by the deposition of Pt nanoparticles (NPs) using an atomic
layer deposition (ALD) technique. The area-specific oxygen reduction
reaction (ORR) activity of Pt@TiO2 catalyst membrane was
increased by ∼20 folds if 10 at.% of Nb was incorporated into
the ceramic fibers. The area-specific activity also increased with
the number of ALD cycles, because of the increase of the Pt loading
in the catalysts. After post-treatment of the catalyst membrane at
high temperature in H2-containing atmosphere, the ORR activity
became 0.28 mA/cm2
Pt at 0.9 V (vs RHE), because
of the improvement in conductivity of Nb-TiO2 fibers and
better crystalinity of Pt NPs. The results of accelerated-stability
test showed that the Pt@Nb-TiO2 catalyst membrane was highly
stable and lost only 10% of its initial activity after 30 000
potential cycles (0.6 to 1.0 V vs RHE) under a strong acidic condition.
Amphiphilic centipede-like brush copolymers with biodegradable poly(ε-caprolactone) and poly(ethyl ethylene phosphate) side segments were prepared by a one-pot syntheses strategy. The syntheses combined ring-opening polymerization of 2-ethoxy-2-oxo-1,3,2-dioxaphospholane through a "grafting from" strategy and "click" reaction with R-propargyl-ω-acetyl-poly(ε-caprolactone) through a "grafting to" strategy, using multifunctional poly(tert-butyl methacrylate)-co-poly(2-hydroxy-3-azidopropyl methacrylate) that bears hydroxyl and azide groups from junction points. The reactions are controllable, and the structure of obtained centipede-like brush copolymer is well characterized. These brush copolymers are amphiphilic and self-assemble into spherical micellar structure in aqueous solution with critical aggregation concentration around 10 -3 mg mL -1 and average diameters of 50-90 nm. Such micelles formed from centipede-like brush copolymers can be used as drug carriers for biomedical applications.
We
herein report the synthesis,
characterization, and anticancer activity of a series of iridium(III)
and ruthenium(II) half-sandwich complexes of the type [(Cpx/arene)M(P^O)Cl]PF6 (M = Ir, Cpx = pentamethylcyclopentadienyl
(Cp*) or its phenyl (Cpxph = C5Me4C6H5) or biphenyl (Cpxbiph = C5Me4C6H4C6H5) derivatives; M = Ru, arene = p-cymene (p-cym); P^O = phosphine phosphonic amide ligand (PPOA)).
The X-ray crystal structures of all complexes, in which the ligand
can form six-membered rings with the metal center, have been determined.
All of the complexes show remarkable anticancer activities toward
HeLa and A549 cancer cells, activities which are higher than that
of the clinical anticancer drug cisplatin. The incorporation of phenyl
substituents on the Cp* ring for iridium(III) complexes results in
little variation in their anticancer activities. These results can
be attributed to the combinatorial action of the metal and PPOA ligand.
Hydrolysis and DNA cleavage are not the major mechanisms of action.
These complexes show potent catalytic activity in the transfer hydrogenation
of NADH to NAD+. Additionally, complexes [(η5-C5Me5)Ir(P^O)Cl]PF6 (1) and [(η6-p-cym)Ru(P^O)Cl]PF6 (4) arrest cell cycles at S and G2/M phase and S phase, respectively. Complexes 1 and 4 both can induce apoptosis of HeLa cancer cells. Reactive
oxygen species (ROS) and mitochondrial membrane potential tests were
also performed to explore the mechanism of action. When the concentration
of the complexes is increased, the amount of reactive oxygen species
(ROS) increases dramatically and the mitochondrial membrane potential
decreases significantly in HeLa cancer cells. Overall, cell stress
including cell cycle perturbation, apoptosis induction, increase in
ROS level, and loss of mitochondrial membrane potential contributes
to the anticancer potency of these complexes. Interestingly, the use
of confocal microscopy provides insights into the microscopic mechanism
in which the typical and most active complex 1 can damage
lysosomes. This type of complex represents a potent platform for development
of metal anticancer drugs.
One restriction to the development and application of transcatheter arterial chemoembolization (TACE) therapy is the lack of an inherently radiopaque embolic whose location and distribution can be precisely visualized in real time and be used for non-invasive examination after surgery.Methods: A one-step electrospray method was developed to fabricate calcium alginate microspheres loaded with tantalum nanoparticles (Ta@CaAlg). The parameters of electrospraying were assessed. The in vivo X-ray imaging capability and embolic effect of Ta@CaAlg microspheres were evaluated in the renal arteries of normal rabbits by digital radiography and computed tomography. Doxorubicin hydrochloride (Dox) was chosen as a model drug, and the drug loading capacity and release behavior of these microspheres was valuated in vitro.Results: Spherical Ta@CaAlg microspheres with monodisperse sizes ranging from 150 to 1200 μm were fabricated by electrospraying. The results of an in vivo study showed that Ta@CaAlg microspheres possessed the qualities of both embolic agents and contrast media. They could not only feed back the real-time location and distribution of the embolic microspheres but also maintained clear X-ray imaging of embolized sites for up to 4 weeks as assessed by digital radiography and computed tomography. Digital subtraction angiography showed that they had an excellent embolic effect. Ta@CaAlg microspheres could be loaded with Dox to form “3-in-1” embolic microspheres. The maximum Dox loading was 97.3 mg Dox per mL beads and loaded microspheres exhibited pH-dependent release profiles.Conclusion: The X-ray opacity and drug-loading capability of Ta@CaAlg microspheres offers great promise in direct, real-time, in vivo investigation for TACE and long-term non-invasive re-examination.
Propofol is an intravenous sedative hypnotic agent of which the growth-inhibitory effect has been reported on various cancers. However, the roles of propofol in endometrial cancer (EC) remain unclear. This study aimed to explore the effects of propofol on EC in vitro and in vivo. Different concentrations of propofol were used to treat Ishikawa cells. Colony number, cell viability, cell cycle, apoptosis, migration, and invasion were analyzed by colony formation, MTT, flow cytometry, and Transwell assays. In addition, the pcDNA3.1-Sox4 and Sox4 siRNA plasmids were transfected into Ishikawa cells to explore the relationship between propofol and Sox4 in EC cell proliferation. Tumor weight in vivo was measured by xenograft tumor model assay. Protein levels of cell cycle-related factors, apoptosis-related factors, matrix metalloproteinases 9 (MMP9), matrix metalloproteinases 2 (MMP2) and Wnt/β-catenin pathway were examined by western blot. Results showed that propofol significantly decreased colony numbers, inhibited cell viability, migration, and invasion but promoted apoptosis in a dose-dependent manner in Ishikawa cells. Moreover, propofol reduced the expression of Sox4 in a dose-dependent manner. Additionally, propofol significantly suppressed the proportions of Ki67+ cells, but Sox4 overexpression reversed the results. Furthermore, in vivo assay results showed that propofol inhibited tumor growth; however, the inhibitory effect was abolished by Sox4 overexpression. Moreover, propofol inhibited Sox4 expression via inactivation of Wnt/β-catenin signal pathway. Our study demonstrated that propofol inhibited cell proliferation, migration, and invasion but promoted apoptosis by regulation of Sox4 in EC cells. These findings might indicate a novel treatment strategy for EC.
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