Rapid, easy and catalyst-free preparation of magnetic thiourea-based covalent organic frameworks at room temperature for enrichment and speciation of mercury with HPLC-ICP-MS.

The complex and cumbersome preparation of magnetic covalent organic frameworks (COFs) nanocomposites on a small scale limits their application. Herein, a rapid and easy route was employed for the preparation of magnetic thiourea-based COFs nanocomposites. COFs were coated on Fe3O4 nanoparticles at room temperature without a catalyst within approximately 30 min. This method is suitable for the large-scale preparation of magnetic adsorbent. Using the as-prepared magnetic adsorbent (Fe3O4@COF-TpTU), we developed a simple, efficient, and sensitive magnetic solid-phase extraction-high performance liquid chromatography-inductively coupled plasma-mass spectrometry (MSPE-HPLC-ICP-MS) for the enrichment and determination of mercury species, including Hg2+, methylmercury (MeHg), and ethylmercury (EtHg). The effects of the experimental parameters on the extraction efficiency, including solution pH, adsorption and desorption time, composition and volume of the elution solvent, salinity, coexisting ions, and dissolved organic matter, were comprehensively investigated. Under optimised conditions, the limits of detection in the developed method were 0.56, 0.34, and 0.47 ng L-1 with enrichment factors of 190, 195, and 180-fold for Hg2+, MeHg, and EtHg, respectively. The satisfactory spiked recoveries (97.0-103%) in real water samples and high consistency between the certified and determined values in a certified reference material demonstrate the high accuracy and reproducibility of the developed method. The as-proposed method with simple operation, high sensitivity, and excellent anti-matrix interference performance was successfully applied to the enrichment and determination of trace levels of mercury species in the natural samples with complicated matrices, such as underground water, surface water, seawater and biological samples.

Gefitinib-resveratrol Cocrystal with Optimized Performance in Dissolution and Stability.

Gefitinib (GEF) is an anti-tumor oral solid formulation with a superior advantage for lung tumors. However, it has poor aqueous solubility which limits its utility in vivo. Herein, a novel cocrystal (GEF-RES) assembled by GEF and RES (Resveratrol) has been successfully prepared and comprehensively characterized by differential scanning calorimetry, thermogravimetric analysis, Raman spectroscopy and powder X-ray diffraction. A single-crystal structure of the GEF-RES cocrystal was solved and illustrated in detail. In aqueous hydrochloric acid, the GEF-RES cocrystal showed that the maximum concentration of GEF was slightly higher than that of raw GEF. Furthermore, the thermal and physical stability of the GEF-RES cocrystal were also evaluated in this paper. The enhanced solubility and excellent solid-state stability results may provide new potential to the application of key GEF in clinical.

2D hydrogen-bonded organic frameworks: in-site generation and subsequent exfoliation.

By using in-site generated formate, 2D HOFs of TCPP, with excellent stability and permanent porosity (BET surface area larger than 560 m2 g-1), have been obtained. The constructed 2D square-like TCPP-HCO2 grid sheets have shown considerable in-plane stability that comparable to the TCPP-based 2D MOFs, that can be exfoliated into atomically thin 2D nanosheets with efficient photocatalytic activity in aqueous system. These results are expected to shed light on the application-orientated one-pot synthesis for new kinds of multi-dimensional HOFs.

Build 3D Nanoparticles by Using Ultrathin 2D MOF Nanosheets for NIR Light-Triggered Molecular Switching.

The coordination interactions between transition-metal ions (Cu2+, Ag+) and sulfur atoms on ultrathin two-dimensional (2D) nanosheets of spin-crossover (SCO) metal-organic frameworks {[Fe(1,3-bpp)2(NCS)2]2}n (1,3-bpp = 1,3-di(4-pyridyl)propane), which constructed the ultrathin 2D nanosheets into three-dimensional (3D) nanoparticles, have made a profound effect on the SCO performance. Compared with 2D nanosheets, both the intraligand π-π* transition band and the metal-to-ligand charge transition band from the d(Fe) + π(NCS) to π*(1,3-bpp), for the 3D nanoparticles, have shown dramatic blue-shifts; meanwhile, the d-d transition band for the high-spin (HS) state Fe(II) ions has been generated, suggesting significantly the influence of 3D assemble-caused dimensional changes on the solid-state SCO performance of ultrathin 2D nanosheets. More importantly, by loading on the ytterbium ion (Yb3+)-sensitized hexagonal phase upconverting nanoparticles in the aqueous colloidal suspension, the near infrared (NIR) light (980 nm) triggered HS (high spin) to LS (low spin) state transitions have been observed, demonstrating the achievement of challenging target of NIR light-triggered molecular conversion under environment conditions.

Near-Infrared Light and pH Dual-Responsive Targeted Drug Carrier Based on Core-Crosslinked Polyaniline Nanoparticles for Intracellular Delivery of Cisplatin.

Biodegradable polymeric nanoparticles have received growing interest as one of the most promising agents for drug delivery. In the present work, functional and core-crosslinked poly(ethylene glycol) with poly(ϵ-caprolactone) (PEG5k -PCL10k ) block copolymer and lecithin as biodegradable polymer doped with polyaniline was used to assemble nanoparticles which were prepared for targeted delivery and controlled release of cisplatin. The morphology of the polyaniline nanoparticles was determined by dynamic light scattering and the prepared nanoparticles showed a size of 83(±1) nm and a uniform spherical shape. For targeting to HER2 receptors, Herceptin was applied to guide the nanoparticles to breast cancer cells. Studies on cellular uptake and drug release of the nanocarriers showed that the prepared nanoparticles were efficiently taken up by breast cancer cells and the drug was released efficiently under acidic conditions when exposed to a near-infrared laser (808 nm, 1.54 W) for 5 min. Our research highlights the great potential of near-infrared light and pH dual-responsive release by core-crosslinked nanoparticles in nanobiomedicine.