Quick synthesis of lipid-polymer hybrid nanoparticles with low polydispersity using a single-step sonication method

Lipid-polymer hybrid nanoparticle, consisting of a hydrophobic polymeric core and a lipid monolayer shell, represents a new and promising drug delivery platform that has shown controllable particle size and surface functionality, high drug loading yield, sustained drug release profile, and excellent in vitro and in vivo stability. These lipid monolayer-coated polymeric nanoparticles are typically fabricated through a modified nanoprecipitation method, which involves sample heating, vortexing, and solvent evaporation. Herein we report a new and fast method to synthesize lipid-polymer hybrid nanoparticles with controllable and nearly uniform particle size. Using a bath sonication approach, we demonstrate that the whole hybrid nanoparticle synthesis process can be completed in about 5 min compared with a few hours for previous synthesis approaches. The size and polydispersity of the resulting nanoparticles can be readily controlled by tuning the relative concentrations of individual building components. Colloidal stability tests of the synthesized hybrid nanoparticles in PBS buffer and serum show no signs of aggregation over a period of 5 days. The present method improves the production rate of the hybrid nanoparticles by near 20-fold while not compromising the physicochemical properties of the particles. This work may facilitate the bench-to-bedside translation of lipid-polymer hybrid nanoparticles as a robust drug nanocarrier by allowing for fabricating a large amount of these nanoparticles at high production rate.     

Thermoresponsive copolymer nanofilms for controlling cell adhesion, growth, and detachment

This study reports the development and use of a novel thermoresponsive polymeric nanofilm for controlling cell adhesion and growth at 37 °C, and then cell detachment for cell recovery by subsequent temperature drop to the ambient temperature, without enzymatic cleavage or mechanical scraping. A copolymer, poly(N-isopropylacrylamide-co-hydroxypropyl methacrylate-co-3-(trimethoxysilyl)propyl methacrylate) (abbreviated PNIPAAm copolymer), was synthesized by free radical polymerization. The thermoresponses of the copolymer in aqueous solution were demonstrated by dynamic light scattering (DLS) through detecting the sensitive changes of copolymer aggregation against temperature. The DLS measurements revealed the lower critical solution temperature (LCST) at approximately 30 °C. The PNIPAAm film stability and robustness was provided through silyl cross-linking within the film and with the hydroxyl groups on the substrate surface. Film thickness, stability, and reversibility with respect to temperature switches were examined by spectroscopic ellipsometry (SE), atomic force microscopy (AFM), and contact angle measurements. The results confirmed the high extent of thermosensitivity and structural restoration based on the alterations of film thickness and surface wettability. The effective control of adhesion, growth, and detachment of HeLa and HEK293 cells demonstrated the physical controllability and cellular compatibility of the copolymer nanofilms. These PNIPAAm copolymer nanofilms could open up a convenient interfacial mediation for cell film production and cell expansion by nonenzymatic and nonmechanical cell recovery.     

pH-Responsive chitosan-mediated graphene dispersions

Homogeneous aqueous suspensions of graphene have been prepared by chemical reduction of graphene oxide in the presence of chitosan. The graphene sheets in thus prepared suspensions can be switched reversibly between a well dispersed and a more aggregated state with pH as a stimulus.     

A Series of Open‐Framework Aluminoborates Templated by Transition‐Metal Complexes

A series of open‐framework aluminoborates (ABOs) [M(dien)₂][AlB₆O₁₁(OH)] (M=Co ( I a ), Ni ( I b ), Cd ( I c ), Zn ( I d ); dien=diethylenetriamine) and [M(en)₃][AlB₇O₁₂(OH)₂] ? (H₂O)_0.25 (M=Co ( II a ), Ni ( II b ); en=ethylenediamine) have been made under hydrothermal conditions and characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis, UV/Vis and fluorescence spectroscopy, powder X‐ray diffraction, single‐crystal X‐ray diffraction, and nonlinear optical determination. These compounds were classified as two structural types: Type I ( I a – d ) contains AlO₄ tetrahedra and B₆O₁₁(OH) clusters, which link to form a new 3D framework with 7‐/9‐ring helical channels and large 13‐ring channels; whereas type II ( II a , b ) is composed of AlO₄ tetrahedra, chainlike B₄O₆(OH)₂ tetramer, and crablike B₆O₁₂ clusters, which interconnect to form other new 3D frameworks with 8‐ring helical channels, rare 16‐ring double‐helical channels, and larger odd 15‐ring channels. These compounds represent the first examples of 3D ABOs templated by transition‐metal complexes (TMCs). I c , d present good second harmonic generation (SHG) properties. UV/Vis spectral investigation indicates that I a – d and II a , b are wide‐band‐gap semiconductors.     

Palladium-catalyzed reduction of alkynes employing HSiEt3: stereoselective synthesis of trans- and cis-alkenes

The palladium-catalyzed semi-hydrogenation of alkynes to trans- or cis-alkenes employing HSiEt₃ as the reductant is developed. The CuSO₄ played a significant role for the trans/cis stereoselectivity. The labeling study revealed that the two olefinic hydrogen atoms came from HSiEt₃ and H₂O, respectively.     

Synthesis and Characterization of Chromium Hexacyanoferrate/Multiwalled Carbon Nanotube Composite and Its Biosensing for L‐Cysteine

This work describes the electrochemical properties of glassy carbon electrodes (GCE) modified with chromium(III) hexacyanoferrate(II) (Crhf) nanoparticles attached multiwalled carbon nanotube (MWNTs). The morphological characterization of Crhf/MWNTs nanocomposites was examined by scanning electron microscopy (SEM), UV‐vis spectroscopy, and Fourier transform infrared spectrometry (FT‐IR). The electrocatalytic activity of these nanocomposites was investigated and showed a good electrocatalytic effect for oxidation of L ‐cysteine (L ‐Cys) in 0.1 M phosphate buffer solution (pH 3.0). Under optimum conditions linear calibration graphs were obtained over the L ‐Cys concentration range 5.0×10^?7 to 6.0×10^?5 M with a correlation coefficient of 0.9998 and a detection limit (signal‐to‐noise ratio was 3) of 1.0×10^?8 M. The proposed method is simple and it also showed excellent sensitivity and stability. The excellent electrocatalytic ability of the modified electrode towards L ‐Cys manifests that the Crhf/MWNTs can provide a new platform for biosensors and other biology.     

Cubic polyoxometalate-organic molecular cage

Tris(hydroxymethyl)aminomethane (Tris) was successfully grafted onto the surface of a Ni(6)-substituted polyoxotungstate formed in situ to further generate a three-connected polyoxometalate building block. The cooperative assembly of Tris functionalized three-connected building blocks and rigid 1,3,5-benzenetricarboxylate gave rise to an unprecedented cubic polyoxometalate-organic molecular cage with high thermal and hydrothermal stability.     

Aminocadambines A and B, two novel indole alkaloids from Neolamarckia cadamba

Two novel monoterpenoid indole alkaloids, aminocadambines A (1) and B (2), characterized by tetrahydrofuran and 1,2,3,4-tetrahydropyridine rings, were isolated from the leaves of Neolamarckia cadamba. Their structures were elucidated on the basis of spectroscopic and computational methods. The absolute configuration of 1 was established by CD analysis. A plausible biosynthetic pathway for 1 and 2 is proposed.     

Synthesis,Structure, and Magnetic Properties of Three Novel Sandwich‐type Tungstobismuthates with Triethanolamine

Three novel sandwich‐type polyoxotungstates ( 1 – 3 ) were synthesized in good yield using an in‐situ conventional solution synthesis method by reaction in aqueous media below 80 °C. Compounds 1 – 3 represent the first structurally characterized β‐B‐BiW₉ sandwich‐type polyoxometalates with triethanolamine cations. All three compounds have the same building unit [(X(H₂O)₃)₂(X_0.5W_0.5O)₂(β‐B‐BiW₉O₃₃)₂)]^10– [X = Mn^II ( 1 ), Co^II ( 2 ), Ni^II ( 3 )]. The adjacent units of 1 or 2 are joined by Na⁺ cations in different ways to construct 1D chains or 2D sheets. A 3D supramolecular structure is further formed by hydrogen bond interactions among water molecules and protonated triethanolamine cations. Meanwhile only compound 3 shows a 0D structure. The compounds were characterized by elemental analysis, IR spectroscopy, TG analysis, and single‐crystal X‐ray diffraction. Magnetic measurements on a sample of 1 show the presence of paramagnetic interactions.     

The performance of a fast testing system for illicit materials detection based on energy-dispersive X-ray diffraction technique

A prototype setup for detecting illicit materials by energy-dispersive X-ray diffraction (EDXRD) has been developed. The obtained results of NaCl by the equipment suggest that the total measurement system is reliable and can be used to detect different kinds of materials. The tests of TNT, methamphetamine and heroin are also performed on this equipment and the related EDXRD spectra are obviously influenced by the detecting angle and the X-ray sources. The detecting angle of 10° is more suitable for detecting TNT and methamphetamine, while 12° is better for heroin. Moreover, the curves of TNT, methamphetamine and heroin emitted by W target have more diffraction peaks than those emitted by Cu or Mo target, while the peak intensities of TNT and methamphetamine emitted by Mo are stronger than those emitted by Cu or W target. The curve of methamphetamine emitted by Mo target shows a special characteristic and exhibits a super strong diffraction peak located at 1.62 Å^{− 1}, which can be attributed to the effect arising from Mo kα and kβ.