Latest ArticlesUsing nanoparticle-based drug delivery systems as enhancers is a robust strategy for transdermal delivery; however, the mechanisms by which these systems promote transdermal penetration are still unclear. Here, we fabricated a dual-labeled nano drug delivery system that allows discrete visualization of both the drug and the nanoparticle carrier. To comprehensively examine its potential mechanism, we investigated its effects on human epidermal keratinocyte HaCaT cells, including changes in cell membrane potential, intracellular Ca2+ concentration, and Ca2+-ATPase activity. P-glycoprotein (P-gp) expression in nanoparticle-treated human dermal microvascular endothelial cells was detected by western blotting and immunofluorescence. Furthermore, the transdermal absorption and biodistribution of the dual-labeled nanoparticles were deeply investigated by skin permeability study in vitro and in vivo using fluorescence microscopy and in vivo imaging, respectively. In addition to reducing membrane potential, increasing the intracellular Ca2+ concentration, and decreasing Ca2+-ATPase activity, our results indicate that the dual-labeled nanoparticles can downregulate P-gp to promote transdermal absorption. Fluorescence and in vivo imaging visually demonstrated that the nanoparticle delivery system penetrated into the dermis through the stratum corneum. All these results indicate that this dual-labeled nano delivery system provides a new method for future in-depth visual explorations of transdermal drug delivery mechanisms.
Pyridinium 1, 4-zwitterionic thiolates were applied to a formal [3 + 2] annulation reaction with modified activated alkynes, affording various tetrasubstituted thiophenes with aryl, alkenyl, alkyl or silyl group at the special position. The structural modification of alkyne substrates enabled the synthesis of diverse thiophenes to be achieved using the pyridinium 1, 4-zwitterionic thiolates as the sulfur-containing building blocks. This approach is metal-free and catalyst-free.
Carbon dots (CDs) are novel fluorescent nanomaterials with good water solubility, high resistance to photobleaching and low toxicity. While, there are few studies elaborate on the relationship among reaction conditions, properties and applications of CDs. In this study, a series of CDs are synthesized through a one-pot hydrothermal method, and different reaction conditions are carried out to study the influencing factors of CDs properties. As a result, with the increase of temperature and reaction time, the particle size and zeta potential of CDs increased, the maximum emission wavelength red-shifted and the fluorescence quantum yield (QY) improved. Among them, CD3006 has good water solubility and highest QY of 81.4%, which is beneficial for its applications in bioimaging and ion detection. CD3006 is almost nontoxic in cells at a concentration of 500 μg/mL. In addition, the positive charged CD3006 shows nuclear targeting potential because of its combination with DNA through electrostatic interaction in nucleus. The properties of CDs can be greatly enhanced by controlling reaction conditions, and it provides great application prospects.
The development of ultra-sensitive methods for detecting anions is limited by their low charge to radius ratios, microenvironment sensitivity, and pH sensitivity. In this paper, a magnetic sensor is devised that exploits the controllable and selective coordination that occurs between a magnetic graphene quantum dot (GQD) and fluoride anion (F–). The sensor is used to measure the change in relaxation time of aqueous solutions of magnetic GQDs in the presence of F‒ using ultra-low-field (118 µT) nuclear magnetic resonance relaxometry. The method was optimized to produce a limit of detection of 10 nmol/L and then applied to quantitatively detect F– in domestic water samples. More importantly, the key factors responsible for the change in relaxation time of the magnetic GQDs in the presence of F‒ are revealed to be the selective coordination that occurs between the GQDs and F‒ as well as the localized polarization of the water protons. This striking finding is not only significant for the development of other magnetic probes for sensing anions but also has important ramifications for the design of contrast agents with enhanced relaxivity for use in magnetic resonance imaging.
The design of assembling high-nuclearity transition-lanthanide (3d-4f) clusters along with excellent magnetocaloric effect (MCE) is one of the most prominent fields but is extremely challenging. Herein, two heterometallic metal coordination polymers are constructed via the "carbonate-template" method, formulated as {[Gd18Ni24(IDA)22(CO3)7(μ3-OH)32(μ2-OH)3(H2O)5Cl]·Cl8·(H2O)14}n and {[Eu18Ni23.5(IDA)22(CO3)7(μ3-OH)32(H2O)5(IN)(CH3COO)2(NH2CH2COO)Cl]·Cl6·(H2O)17}n [abbreviated as 1-(Gd18Ni24)n and 2-(Eu18Ni23.5)n respectively; H2IDA = iminodiacetic acid; HIN = isonicotinic acid]. Concerning the structures, compounds 1-(Gd18Ni24)n and 2-(Eu18Ni23.5)n both feature the one-dimensional (1D) chain-like structure which is rarely reported in high-nuclearity metal complexes. Meanwhile, the large presences of Gd3+ ions in compound 1-(Gd18Ni24)n are conducive to the fantastic MCE, and the value of -∆Sm is 35.30 J kg-1 K-1 at 3.0 K and ∆H = 7.0 T. And more significantly, compound 1-(Gd18Ni24)n shows the large low-field magnetic entropy change (-∆Sm = 20.95 J kg-1 K-1 at 2.0 K and ∆H = 2.0 T) among the published 3d-4f mixed metal clusters.
Thrombotic disease is a major problem that endangers human health. At present, MRI and CT are commonly used clinically to diagnose thrombosis, and thrombolytic drugs are used for treatment), but the diagnosis time is lagging, the utilization of drugs is low, and the resulting systemic toxicity problems such as side effects lead to poor treatment effects. Nanotechnology combining photoacoustic dynamics and chemical dynamics has shown great application value in tumor targeting, diagnosis, detection and treatment. It has also become a new direction in the diagnosis and treatment of thrombotic diseases, and has created new applications in the field of nanomaterials. This review summarizes the new progress of this combination in the diagnosis and treatment of thrombotic diseases according to the differences in the construction of the nanotherapy system, at the same time, we put forward some new problems and prospects for the integration of thrombosis diagnosis and treatment.
Selective detection of multiple analytes in a compact design with dual-modality and theranostic features presents great challenges. Herein, we wish to report a coumarin-thiazolidine masked D-penicillamine based dual-modality fluorescent probe COU-DPA-1 for selective detection, differentiation, and detoxification of multiple heavy metal ions (Ag+, Hg2+, Cu2+). The probe shows divergent fluorescence (FL) /circular dichroism (CD) responses via divergent bond-cleavage cascade reactions (metal ion promoted C-S cleavage and hydrolysis at two distinctive cleavage sites): FL "turn-off" and CD "turn-on" for Ag+ (no hydrolysis), FL "turn-on" and CD "turn-off" for Hg2+ (imine hydrolysis), and FL "self-threshold ratiometric" and CD "turn-off" for excess Cu2+ (lactone and imine hydrolysis), providing the first example of a fluorescence/CD dual-modality probe for multiple species with complimentary responses. Moreover, the bond-cleavage cascade reactions also lead to the formation of D-penicillamine heavy metal ion complexes for potential detoxification treatments.
A HAT based large PAH discotic molecule PN8 is developed. The enlarged chromophoric core and doping heteroatoms enable colorimetric and fluorometric sensing of Cu2+ and Zn2+ with highly appreciable optical changes, good selectivity and low detection limit. Moreover, PN8 was demonstrated as an excellent adsorbent to remove Cu2+ and Zn2+ from wastewater.
The bio-nanotechnological fabrication of high-surface-area carbons has attracted widespread interest in supercapacitor applications by using readily-available natural products as raw materials or bio-templates, and is expected to refine on pore accessibility for compact energy storage. Here, a renovated design strategy of semi-biomass interpenetrating polymer network (IPN) derived carbon is demonstrated through physically knitting the biomacromolecule (sodium alginate, SA) polymeric chains into the highly crosslinked resorcinol-formaldehyde (RF) network and subsequent thermochemical conversion. Molecule-level interlacing forces in such IPN efficiently relieve the RF skeleton shrinkage when producing carbon, while the other SA network addresses the macrophase separation issue to sacrifice as an in-knitted porogen and a morphology-directing agent. As a result, porous carbon globules are equipped with moss-like surfaces and interconnected pore architecture for high accessible electrode surface (1013 m2/g), and efficient electrochemical responses are reached with the specific capacitance of 312 F/g at 1 A/g. Taking the advantage of 9 mol/kg NaClO4 complex-solvent electrolyte, the voltage window is extended to 2.4 V, endowing the two-electrode device with the high energy delivery of 32.3 Wh/kg at 240 W/kg.
Introduction of iodosylarnes into biomimetic nonheme chemistry has made great achievement on identification of the subtle metal-oxygen reaction intermediates. However, after more than three decades of experimental and theoretical efforts the nature of the metal-iodosylarene adducts and the related dichotomous one-oxidant/multiple-oxident controversy have remained a matter of speculation. Herein, we report a theoretical study of the structure-activity relationship of the noted iron(Ⅲ)-iodsylarene complex, FeⅢ(PhIO)(OTf)3 (1), in oxygenation of cyclohexene. The calculated results revealed that 1 behaves like a chameleon by adapting its roles as a 2e-oxidant or an oxygen donor, as a response to the regioselective attack of the C–H bond and the C=C bond. The oxidative C–H bond activation by 1 was found, for the first time, to proceed via a novel hydride transfer process to form a cyclohexene carbonium intermediate, such non-rebound step triggers the Ritter reaction to uptake an acetonitrile molecule to form the amide product, or proceeds with the rebound of the hydroxyl group return to the solvent cage to form the hydroxylated product. While in the C=C bond activation, 1 is a normal oxygen donor and shows two-state reactivity to present the epoxide product via a direct oxygen atom transfer mechanism. These mechanistic findings fit and explain the famous Valentine's experiments and enrich the non-rebound scenario in bioinorganic chemistry.
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