Latest ArticlesAlthough titanate nanofibers (TiNFs) and titanate nanotubes (TiNTs) have been proposed as relatively biocompatible nanomaterials (NMs), there is currently lacking of systemic studies which investigated the toxicity of TiNFs and TiNTs to endothelium. In this study, we developed endothelial monolayer model by using cell culture inserts, and systemically investigated the toxicity of TiNFs and TiNTs by RNA-seq, with a focus on Kruppel-like factor (KLF)-mediated effects, since KLF are transcription factors (TF) involved in the regulation of vascular biology. It was shown that NMs did not significantly induce cytotoxicity despite substantial internalization. However, the expression of many KLF was altered, and Western blot further confirmed that NMs down-regulated KLF2 proteins. Ingenuity pathway analysis (IPA) revealed that NMs altered the expression of KLF2-targed genes, typically the genes involved in inflammatory responses. KLF2-related Gene Ontology (GO) terms and Kyoto Encyclopedia of Gene and Genomes (KEGG) pathways were also altered, and it should be noticed that NMs altered GO terms and KEGG pathways related with endothelial NO synthase (eNOS). This study further verified that NMs decreased intracellular NO and eNOS proteins. All the observed effects were more obvious for TiNFs compared with TiNTs. Combined, this study showed that TiNFs or TiNTs were non-cytotoxic to endothelial monolayer model, but TiNFs and more modestly TiNTs decreased KLF2 leading to decreased eNOS proteins and NO production. Our data may provide novel understanding about the toxicity of TiNFs as well as other Ti-based NMs to endothelium.
A new nonporous Zn-based metal-organic framework (NPMOF) synthesized from a high nitrogen-containing rigid ligand was converted into porous carbon materials by direct carbonization without adding additional carbon sources. A series of NPMOF-derived porous carbons with very high N/O contents (24.1% for NPMOF-700, 20.2% for NPMOF-800, 15.1% for NPMOF-900) were prepared by adjusting the pyrolysis temperatures. The NPMOF-800 fabricated electrode exhibits a high capacitance of 220 F/g and extremely large surface area normalized capacitance of 57.7 μF/cm2 compared to other reported MOF-derived porous carbon electrodes, which could be attributed to the abundant ultramicroporosity and high N/O co-doping. More importantly, symmetric supercapacitor assembled with the MOF-derived carbon manifests prominent stability, i.e., 99.1% capacitance retention after 10,000 cycles at 1.0 A/g. This simple preparation of MOF-derived porous carbon materials not only finds an application direction for a variety of porous or even nonporous MOFs, but also opens a way for the production of porous carbon materials for superior energy storage.
As a potent anticancer drug, gambogic acid (GA) suffers from its poor water solubility and low chemical stability and shows a limited clinical outcome. To address this problem, we report here a simple and effective strategy to immobilize and deliver GA using a reducible diblock poly(amino acid) as a model. The electrostatic interaction between GA and polymer enables a high drug loading content up to 53.6 %. Moreover, the drug complexation induces a micelle-to-vesicle transformation, combined with a conformation transition from random coil to α-helix. The hierarchically assembled drug nanocomplexes can serve as a smart carrier for efficient cell internalization and triggered release of multiple drugs under intracellular acidic and reductive conditions, resulting in a synergistic antitumor efficacy in vitro. This work provides a new insight into the drug-carrier interaction and a facile nanoplatform for drug delivery applications.
An efficient Pd-catalyzed double annulation reaction of 1-(2, 6-dibromophenyl)-1 H-pyrroles with arynes is developed to synthesize π-extended dibenzo[d, k]ullazines in good to excellent yields. For the first time, the parent dibenzo[d, k]ullazine core is obtained and characterized.
The urgent need for fresh water resource is a public issue facing the world. Solar distillation for seawater desalination is a promising freshwater production method. Interfacial solar evaporation systems based on 2D photo-thermal membranes have been widely studied, but salt pollution is one of the main challenges for solar distillation. In order to solve this problem, a hydrophilic three-dimensional (3D) porous photo-thermal fiber felt (PFF) was obtained by one-step method, through a simple polydopamine (PDA) coating method with hydrophobic graphite felt as a substrate. The PFF had a good evaporation rate of 1.48 kg/m−2h-1 and its corresponding light-vapor conversion efficiency reached 87.4%. In addition, the PFF exhibited an excellent salt-resistant ability when applied to photo-thermal evaporation of high-salinity seawater with 10 wt% NaCl, owing to its intrinsic 3D macroporous structure for the migration circulation of salt ions. The development of the PFF offers a new route for the exploration of salt-resistant photo-thermal materials and is promising for the practical application of solar distillation.
The recent Ir/Pd co-catalyzed photo carboxylation of aromatic halides with CO2 has shown high efficiency and excellent functional group tolerance for preparing aromatic carboxylic acids and esters. With the aid of density functional theory (DFT) calculations, the carboxylation starts with two parallel steps, i.e., oxidative addition of aromatic halides on Pd0 and reductive quenching of the photocatalyst Ir(ppy)2(dtbpy)+ with amine. Thereafter, a successive oxidation of PdⅡ with the amine radical (generated by the reaction of cationic radical amine and Cs2CO3) and IrⅡ species occurs to generate Pd0, from which the carboxylation occurs easily via a coordination, Pd-C insertion step. The release of the carboxylate product then regenerates the catalyst.
Aflatoxin B1 (AFB1) is one of the most toxic, mutagenic and carcinogenic mycotoxin, widely exists in contaminated food, grains and feedstuff products. In this study, a novel magnetic beads multicolor colorimetric immunoassay (MBMCIA) based on Au@Ag nanorods (Au@Ag NRs) is proposed to visual detect ultralow concentration of AFB1 with high-resolution by the naked-eye. To design the MBMCIA system, AFB1-BSA conjugates were first coated on the surface of magnetic beads (MBs), then alkaline phosphatase (ALP) as a bridge between immunoassay and color reaction was used for catalytic hydrolysis of ascorbic acid-phosphate to generate reductive ascorbic acid. Finally, the yielded ascorbic acid could reduce silver ions to grow a silver coating on the surface of gold nanorods to generate Au@Ag NRs, which leads to the bule-shifted longitudinal absorption peak of Au NRs, accompanying with a series of perceptible color change. Under the optimal conditions, the proposed MBMCIA exhibited good sensitivity and specificity for the detection of AFB1 with the detection limit as low as 5.7 pg/mL. Meanwhile, the MBMCIA was also applied for the analysis of AFB1 in spiked wheat samples, the obtained recoveries range from 99.1% to 104.3% with relative standard deviation (RSD) less than 7.05% were acceptable. The proposed MBMCIA integrates separated, enriched, anti-interference and signal read-out into one, which opens up a new avenue for an on-site visual food safety inspection or environmental monitoring.
Metal organic frameworks (MOFs) derived carbonaceous materials have a wide range of applications in the fields of energy storage, catalysis, adsorption and separation, etc. Especially, zeolitic imidazolate framework-8 (ZIF-8) is an excellent candidate to synthesize porous carbon due to the large surface area and high nitrogen content. However, the dominated microporous structure of ZIF-8-derived carbon significantly hinders ionic mass transfer, limiting the improvement of performance. Herein, MOF-derived mesoporous carbon was prepared using ZIF-8 as carbon precursor and cheap sodium silicate (Na2SiO3) as activator. The introduction of Na2SiO3 created rich mesoporous structure and increased specific surface area, as well as the effects of pyrolysis temperature and Na2SiO3 dosage on performance was also investigated. The obtained ZIF-derived porous carbon exhibits good electrochemical performance with specific capacitance of 263 F/g at 1 A/g and excellent cycle life (96.07% after 10,000 GCD cycles) in supercapacitor. The use of cheap Na2SiO3 activator provides a new orientation for the preparation of MOF-derived carbons with rich pores, high surface area, and facilitates the large-scale application of MOF-derived carbons.
As a vital nutrient closely related to the cancer-cells proliferation, phosphate anions have been paid great attention as a promising anticancer agent. Generally, the transport of phosphate anions depends on a protein transport system which is regulated by ion homeostasis regulations. Herein, we designed a reactive anionic nanocarrier based on black phosphorus nanosheets (BPs) and artesunate (ART), which could enter cells through endocytosis to generate phosphate anions, avoiding the regulation of cell homeostasis. The ionic nanocarrier was coated by polydopamine to defend BPs and ART and functionalized by folate (FA) and hyaluronic acid (HA) for targeting factor. With the anchoring groups FA/HA targeted the carrier into cells, polydopamine coating decomposed to expose ART for further generating reactive oxygen species (ROS) in cancer cell microenvironment, providing oxidation conditions. Next, ROS generated by ART makes BPs decompose to phosphate anions with effectively speed, giving rise to the destruction of ion homeostasis to induce necrosis and inhibit the proliferation for cancer cells. In consequence, this research provides novel idea and direction for the ionic carriers and tumor therapeutics.
The design of supramolecular systems with efficient singlet oxygen generation has attracted considerable interests. Herein, an AIE-based singlet oxygen generation system with chemiluminescence properties is reported in aqueous media based on supramolecular host-guest assembly between a water-soluble pillar[5]arene (WP5) and an AIE photosensitizer (TPEDM). The formed supramolecular nanoparticles exhibit significant singlet oxygen generation ability as well as enhanced fluorescence. In addition, by introducing catalase, this H2O2-responsive supramolecular system shows increased 1O2 generation efficiency compared with the blank nanoparticles. An efficient chemiluminescence system can also be achieved by entrapping an energy donor adamantane derivative (AMPPD). Moreover, the present system can function as nanoreactors to perform the photooxidation of dopamine to form polydopamine with visible light irradiation. This work provides a new strategy for the construction of 1O2 generation system based on supramolecular nanomaterials, which has potential applications in the fields such as chemiluminescence imaging and controlled photocatalysis.
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