MC8 Peptide-Mediated Her-2 Receptor Targeting Based on PEI-β-CyD as Gene Delivery Vector

A novel vector with high gene delivery efficiency and special cell targeting ability was developed using a good strategy that utilized low molecular weight polyethylenimine (PEI; molecular weight, 600 KDa [PEI600]) cross-linked to β-cyclodextrin (β-CyD) via a facile synthetic route. Human epidermal growth factor receptor 2 (Her-2) are highly expressed in a variety of human cancer cells and are potential targets for cancer therapy. MC8 peptides, which have been proven to combine especially with Her-2 on cell membranes were coupled to PEI-β-CyD using N-succinimidyl-3-(2-pyridyldithio) propionate as a linker. The ratios of PEI600, β-CyD, and peptide were calculated based on proton integral values obtained from the ¹H-NMR spectra of the resulting products. Electron microscope observations showed that MC8-PEI-β-CyD can efficiently condense plasmid DNA (pDNA) into nanoparticles of about 200 nm, and MTT assays suggested the decreased toxicity of the polymer. Experiments on gene delivery efficiency in vitro showed that MC8-PEI-β-CyD/pDNA polyplexes had significantly greater transgene activities than PEI-β-CyD/pDNA in the Skov3 and A549 cells, which positively expressed Her-2, whereas, no such effect was observed in the MCF-7 cells, which negatively expressed Her-2. Our current research indicated that the synthesized nonviral vector shows improved gene delivery efficiency and targeting specificity in Her-2 positive cells.     

Recombinant Expression and Characterization of an Organic-Solvent-Tolerant α-Amylase from Exiguobacterium sp. DAU5

The enzyme from halophilic microorganisms often has unique properties such as organic-solvent-tolerance. In this study, a novel organic-solvent-tolerant α-amylase gene was cloned from the mild halophile Exiguobacterium sp. DAU5. The open reading frame (ORF) of the enzyme consisted of 1,545 bp and encoded 514 amino acids, the primary sequence revealed that it belongs to the glycoside hydrolase (GH) family 13. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) showed an AmyH monomer of 57 kDa. The enzyme exhibited maximal activity at 40 °C in pH?8.5 glycine–NaOH buffer, and the activity was strongly inhibited by Zn²⁺, Cu²⁺, and Fe²⁺. The α-amylase AmyH exhibited high hydrolysis activity toward soluble starch, and the major hydrolysis products were maltose, maltotriose, and maltopentaose; the AmyH could not efficiently hydrolyze oligosaccharides smaller than maltoheptaose, nor could it act on the β-1,4 or α-1,6 glucosidic bonds in xylan or pullulan, respectively. In addition, the α-amylase exhibited better tolerance to organic solvents, as it was stable in the presence of dimethylsulfoxide (DMSO), methanol, ethanol, and acetone. Base on all of these results, the enzyme could be useful for practical application in the bakery industry and in biotechnological processes that occur in the presence of organic solvents.     

A Novel Polysaccharide from Lentinus edodes Mycelia Exhibits Potential Antitumor Activity on Laryngeal Squamous Cancer Cell Line Hep-2

A novel polysaccharide [Lentinus edodes mycelia polysaccharide 2 (LMP2)] with a molecular weight of 2.27?×?10⁴ Da was isolated from the Lentinus edodes mycelia and purified by Sephadex G-200 and diethylaminoethyl-32 column chromatography. HPLC results indicated that LMP2 contained mannose, arabinose, galactose, xylose, and rhamnose with a relative molar ratio of 1:0.74:3.23:1.18:10.98. Its antitumor activity was evaluated in vitro by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, colony formation assay, and transwell assay. LMP2 showed a remarkable inhibitory effect on the proliferation of Hep-2 cells, and at the concentration of 200 mg/ml, the inhibition ratio was 37.2 % after 72 h. Furthermore, colony formation of Hep-2 cells was reduced significantly after treatment with LMP2. Invasion of Hep-2 cells was inhibited significantly by LMP2. These results suggested that LMP2 could be explored as a potential antitumor material for laryngeal carcinoma.     

Development of dispersive liquid-phase microextraction based on new ionic liquid 1,3-diisooctylimidazolium hexafluorophosphate as solvent for the extraction and determination of dicofol and its degradation products in water samples

In the current paper we describe a novel sample preparation technique termed dispersive liquid-phase microextraction for the preconcentration and determination of 2,2,2-trichloro-1,1-bis(4-chlorophenyl)ethanol (dicofol) and its degradation products in water samples that includes 2-(2-chlorophenyl)-2-(4-chlorophenyl)-1,1-dichloroethene(2,4′-DDE), 1,1-dichloro-2,2-bis(4-chlorophenyl)ethane(4,4′-DDE) and 1,1,1-trichloro-2-(2-chlorophenyl)-2-(4-chlorophenyl)ethane (2,4′-DDT) coupled with gas chromatography mass spectrometry (GC-MS), in which a new ionic liquid 1,3-diisooctylimidazolium hexafluorophosphate abbreviated as [D(i-C₈)IM][PF₆] was used as extraction solvent. For each one extraction, 1.00 mL of the methanol solution containing 40 µL of the ionic liquid was sprayed into 25.00 mL of water sample. In the meantime the ionic liquid was finely dispersed into the aqueous phase and analytes were rapidly migrated into the ionic liquid. After the solution was centrifuged for 2 min at 5000 rpm, the droplets of the ionic liquid are subsided in the bottom of the conical test tube (30.0 ± 0.2 µL). Moreover, the factors relevant to extraction efficiencies were investigated and optimised including the volume of the ionic liquid, disperser solvent, extraction time, sample pH and ionic strength. Under optimal conditions, the enrichment factors of the extraction were between 550 and 725 with an extraction efficiency ranging from 66% to 87% for each different analyte. Finally, 1.0 µL of the ionic liquid collected from above extraction was injected into the injector block of GC-MS instrument for analysis. The detection limit (S/N = 3), the relative standard deviations for 2.0 µg L^?1 of the standard analyte (n = 5) and linearity in a calibration range were found to be 3–8 ng L^?1, 1.0–2.7% and 10–3000 ng L^?1, respectively. Good spiked recoveries over the range of 92.0–13.5% were obtained. The proposed method offers the advantages of simplicity of operation, rapidity, good extraction efficiency and enrichment factor; it has been successfully applied to determination of dicofol and its degradation products in environmental water samples.     

Biomimetic synthesis of calcium carbonate with different morphologies under the direction of different amino acids

Using three different amino acids (AAs) as organic matrices, including the highly nonpolar hydrophobic l-valine, the positively charged l-arginine and the less polar uncharged l-serine, calcium carbonate (CaCO₃) with different morphologies and polymorphs were synthesized by a facile gas diffusion reaction based on biomimetic strategy. Compared with the control cubic calcite obtained in the absence of AAs, the product from l-valine was cubic calcite aggregates assembled by nano-platelets. The product from l-arginine was spherical vaterite aggregates assembled by spherical nanoparticles. The product from l-serine was the mixture of cubic calcite and spherical vaterite. The structures and properties of the side chains of the AAs exerted the significant effects on the nucleation and growth of the CaCO₃. The formation mechanisms of the CaCO₃ in the presence of AAs are preliminarily discussed. The results suggest that the polymorphs and morphologies of the inorganic nanomaterials might be easily adjusted through the careful selection of the organic matrices.     

Excellent degradation performance of azo dye by metallic glass/titanium dioxide composite powders

The metallic glass/titanium dioxide powders (MG/TiO₂) with enhanced photocatalytic oxidation activity were synthesized, which exhibit a higher efficiency in decolorizing methylene blue solutions (MB). Compared with the pure TiO₂ and crystalline alloy/TiO₂ (CA/TiO₂) under the same circumstances, its degradation rate was 60 % and 30 % higher, respectively. Furthermore, compared with the CA/TiO₂, the MG/TiO₂ photocatalytic rate was three times faster when decolorizing MB. Considering the excellent intrinsic high-performance photocatalytic degradation under visible light irradiation, these novel powders were proven to have potential applications in water purification industry.     

Nitrogen‐Doped Carbon Dots: A Facile and General Preparation Method,Photoluminescence Investigation,and Imaging Applications

Carbon dots (Cdots) are an important probe for imaging and sensing applications because of their fluorescence property, good biocompatibility, and low toxicity. However, complex procedures and strong acid treatment are often required and Cdots suffer from low photoluminescence (PL) emission. Herein, a facile and general strategy using carbonization of precursors and then extraction with solvents is proposed for the preparation of nitrogen‐doped Cdots (N‐Cdots) with 3‐(3,4‐dihydroxyphenyl)‐L ‐alanine (L ‐DOPA), L ‐histidine, and L ‐arginine as precursor models. After they are heated, the precursors become carbonized. Nitrogen‐doped Cdots are subsequently extracted into N,N′‐dimethylformamide (DMF) from the carbogenic solid. A core–shell structure of Cdots with a carbon core and the oxygen‐containing shell was observed. Nitrogen has different forms in N‐Cdots and oxidized N‐Cdots. The doped nitrogen and low oxidation level in N‐Cdots improve their emission significantly. The N‐Cdots show an emission with a nitrogen‐content‐dependent intensity and Cdot‐size‐dependent emission‐peak wavelength. Imaging of HeLa cells, a human cervical cancer cell line, and HepG2 cells, a human hepatocellular liver carcinoma line, was observed with high resolution using N‐Cdots as a probe and validates their use in imaging applications and their multicolor property in the living cell system.     

A p‐Quinodimethane‐Bridged Porphyrin Dimer

A p‐quinodimethane (p‐QDM)‐bridged porphyrin dimer 1 has been prepared for the first time. An unexpected Michael addition reaction took place when we attempted to synthesize compound 1 by reaction of the cross‐conjugated keto‐linked porphyrin dimers 8 a and 8 b with alkynyl/aryl Grignard reagents. Alternatively, compound 1 could be successfully prepared by intramolecular Friedel–Crafts alkylation of the diol‐linked porphyrin dimer 14 with concomitant oxidation in air. Compound 1 shows intense one‐photon absorption (OPA, λ_max=955 nm, ε=45400 M ^?1 cm^?1) and a large two‐photon absorption (TPA) cross‐section (σ⁽²⁾_max=2080 GM at 1800 nm) in the near‐infrared (NIR) region due to its extended π‐conjugation and quinoidal character. It also exhibits a short singlet excited‐state lifetime of 25 ps. The cyclic voltammogram of 1 displays multiple redox waves with a small electrochemical energy gap of 0.86 eV. The ground‐state geometry, electronic structure, and optical properties of 1 have been further studied by density functional theory (DFT) calculations and compared with those of the keto‐linked dimer 8 b . This research has revealed that incorporation of a p‐QDM unit into the porphyrin framework had a significant impact on its optical and electronic properties, leading to a novel NIR OPA and TPA chromophore.     

Solid‐State Structural Transformations and Photoreactivity of 1D‐Ladder Coordination Polymers of PbII

An attempt has been made to design double‐stranded ladder‐like coordination polymers (CPs) of hemidirected Pb^II. Four CPs, [Pb(μ‐bpe)(O₂C‐C₆H₅)₂] ? 2H₂O ( 1 ), [Pb₂(μ‐bpe)₂(μ‐O₂C‐C₆H₅)₂(O₂C‐C₆H₅)₂] ( 2 ), [Pb₂(μ‐bpe)₂(μ‐O₂C‐p‐Tol)₂(O₂C‐p‐Tol)₂] ? 1.5 H₂O ( 3 ) and [Pb₂(μ‐bpe)₂(μ‐O₂C‐m‐Tol)₂(O₂C‐m‐Tol)₂] ( 4 ) (bpe=1,2‐bis(4′‐pyridyl)ethylene), have been synthesised and investigated for their solid‐state photoreactivity. CPs 2 – 4 , having a parallel orientation of bpe molecules in their ladder structures and being bridged by carboxylates, were found to be photoreactive, whereas CP 1 is a linear one‐dimensional (1D) CP with guest water molecules aggregating to form a hydrogen‐bonded 1D structure. The linear strands of 1 were found to pair up upon eliminating lattice water molecules by heating, which led to the solid‐state structural transformation of photostable linear 1D CP 1 into photoreactive ladder CP 2 . In the construction of the double‐stranded ladder‐like structures, the parallel alignment of C?C bonds in 2 – 4 is dictated by the chelating and μ₂‐η²:η¹ bridging modes of the benzoate and toluate ligands. The role of solvents in the formation of such double‐stranded ladder‐like structures has also been investigated. A single‐crystal‐to‐single‐crystal transformation occurred when 4 was irradiated under UV light to form [Pb₂(rctt‐tpcb)(μ‐O₂C‐m‐Tol)₂(O₂C‐m‐Tol)₂] ( 5 ).