Dual-response nanocarrier based on graft copolymers with hydrazone bond linkages for improved drug delivery

Core–shell micelles with biodegradability, thermo- and pH-response were successfully demonstrated by poly(2-oxepane-1,5-dione-co-ɛ-caprolactone) (P(OPD-co-CL)) grafted with hydrophilic segments of amine-terminated poly(N-isopropylacrylamide) (At-PNIPAM). To compare with the graft copolymer, P(OPD-co-CL) block PNIPAM polymer was also prepared. The micelles with core–shell structure were formed with both graft and block copolymers by self-assembly in aqueous solutions, of which PNIPAM shell is thermo-response. Furthermore, P(OPD-co-CL)-g-PNIPAM also showed pH-sensitivity, which was attributed to the acid-cleavable property of the hydrazone bond. The low critical micelle concentrations (CMCs) of graft polymers and block polymers were 6.7 mg/L and 14.3 mg/L, respectively, which indicated the formation of stable micelles. Both drug-free and drug-loaded micelles were in uniformly spherical shape observed by transmission electron microscopy (TEM). The sizes of the drug-free and drug-loaded micelles prepared from graft polymer were 123.5 nm and 146.5 nm, respectively, and the sizes of those prepared from block polymer were 197.5 nm and 211.5 nm, respectively. The lower critical solution temperature (LCST) for the graft polymer was 34.3 °C, while that for the block polymer was 28.1 °C, demonstrating a thermo-response. The graft polymeric micelles exhibited thermo-triggered decelerated release at pH 7.4, and pH-triggered accelerated release at 25 °C in vitro release test, indicating that the graft polymeric micelles could be a promising site-specific drug delivery system for enhancing the bioavailability of the drug in targeted pathological areas.     

One-pot photoreduction to prepare NIR-absorbing plasmonic gold nanoparticles tethered by amphiphilic polypeptide copolymer for synergistic photothermal-chemotherapy

We developed one-pot photoreduction strategy to fabricate the NIR-absorbing plasmonic PLC-b-PEO@Au NPs. It possessed strong NIR absorption at 700-1100 nm, an ultrahigh photothermal conversion efficiency of 62.1%, and good photostability.     

Ultrafine molybdenum carbide nanoparticles supported on nitrogen doped carbon nanosheets for hydrogen evolution reaction

Nitrogen doped carbon nanosheets supported molybdenum carbides nanoparticles (Mo_xC/NCS) have been synthesized by tuning the mass ratio of melamine and ammonia molybdate. The Mo₂C/NCS-10 exhibits superior electrocatalytic performance and stability for HER, which was attributed to N-doped carbon nanosheets, small particle size, mesoporous structure, and large electrochemical active surface area.     

Novel dual inhibitors against FP-2 and PfDHFR as potential antimalarial agents: Design,synthesis and biological evaluation

A series of novel 2,4-diaminopyrimidine-modified compounds was designed and synthesized. Compound 14 showed micromolar dual inhibitory effect on both FP-2 and PfDHFR, and potential inhibition to the proliferation of P. falciparum 3D7 strain and chloroquine-resistant P. falciparum Dd2 strain.     

Super-resolution morphological dissemination of intercalating dye in single DNA molecules via binding activated localization microscopy

Super-localization of intercalating dye YOYO-1 in single λ-DNA at super-resolution by binding activation localization microscopy (BALM).     

A novel method for Co(Ⅱ) and Cu(Ⅱ) analysis by capillary electrophoresis with chemiluminescence detection

Based on the fact that some metal ions can catalyze the chemiluminescence(CL)reaction of luminol with K_3Fe(CN)_6,a novel capillary electrophoresis CL method was developed for the determination of Co(Ⅱ)and Cu(Ⅱ).The separation was carried out with a 10 mmol/L sodium acetate solution containing 0.8 mmol/L luminol and 2.0 mmol/Lα-HIBA(adjusted to pH 4.8 by HAc solution).The post-capillary reagent was 2.0 mmol/L K_3Fe(CN)_6 which was adjusted to pH 13.0 by NaOH solution.Under the optimum conditions,the detection limits(S/N=3)for Co(Ⅱ)and Cu(Ⅱ)were 7.5×10~(-11)mol/L and 7.5×10~(-9)mol/L,with the linear range of 7.5×10~(-9)mol/L to 1.0×10~(-6)mol/L and 7.5×10~(-8)mol/L to 5.0×10~(-5)mol/L, respectively.     

In-line Raman spectroscopy and advanced process control for the extraction of anethole and fenchone from fennel (Foeniculum vulgare L. MILL.)

Plants are a desirable source for molecules of all kinds and for every purpose. Besides traditional techniques for extraction, plants are challenging for modern process engineering due to great variations because of their natural origin. One way to ensure high quality and low costs, as well as highly resource-efficient extraction, is in-line monitoring and process control. This study demonstrates the use of in-line Raman spectroscopy for monitoring the extraction of anethole and fenchone from fennel seed as a typical example. A partial least square calibration model with high accuracy was created. (Anethole: R² = 0.99, root mean square error of calibration (RMSEC) = 0.01256 g/L, root mean square error of validation (RMSEV) = 0.02608 g/L, and calibration range up to 2 g/L. Fenchone: R² = 0.98, RMSEC = 0.01188 g/L, RMSEV = 0.01945 g/L, and calibration up to 0.75 g/L.) These data are directly linked to a physicochemical process model to control the extraction process in real time and to perform predictive simulations while processing. The added value of this approach for modern phytoextraction is highlighted and exemplified as a major step toward sustainable Green Extraction processes.     

Rapid determination of illegal additives chrysoidin and malachite green by surface-enhanced Raman scattering with silanized support based substrate

Silanized support based SERS substrate is applied to detect chrysoidin in Sprite at 0.01 mg/L and malachite green in fish pond water at 0.0001 mg/L. The SERS method is sensitive, cost-effective and convenient, which has great potential in detection of illegal additives and harmful substances.     

Anionic polymerization initiated by lithium amides for preparing high molecular weight polyacrylonitrile

Lithium amides have been proved to be effective anionic initiators for the anionic polymerization of acrylonitrile to get high molecular weight polyacrylonitrile in this study. Polyacrylonitrile with weightaverage molecular weight ranging from 1.02 × 10~6 g/mol to 1.23 ×10~6 g/mol (M_w/M_n= 1.9-2.2) could be prepared utilizing lithium amides derived from diisopropylamine, diethylamine, hexamethyldisilazane,dicyclohexylamine, and 2,2,6,6-tetramethylpiperidine as initiators. The polymerization of acrylonitrile proceeded in a homogeneous manner in N,N-di methyl for mamide and insignificant contribution of side reactions was confirmed.     

Evaluation of necrosis avidity of radioiodinated 5-hydroxytryptophan and its potential applications in myocardial infarction imaging

[¹³¹I]5-HTP features predominant necrosis avidity and could rapidly visualize necrotic myocardium at 3 h p.i. The necrosis avidity mechanism of [¹³¹I]5-HTP may be attributed to its interactions with E-DNA in the necrotic tissues.     

Polyimide-derived carbon nanofiber membranes as anodes for high-performance flexible lithium ion batteries

Heteroatoms-doped carbon nanofiber membranes with flexible features were prepared by electrospinning with heterocyclic polyimide (PI) structures containing biphenyl and pyrimidine rings. The products with optimized treatment could achieve 695 mAh/g at 0.1 A/g and retain 245 mAh/g at 1.5 A/g after 300 cycles when used as anode for Li-ion batteries.     

Novel amphiphilic triblock copolymer based on PPDO,PCL, and PEG: Synthesis,characterization, and aqueous dispersion

Amphiphilic triblock copolymer, poly(p-dioxanone-co-caprolactone)-block-poly(ethylene oxide)-block-poly(p-dioxanone-co-caprolactone) (PPDO-co-PCL-b-PEO-b-PPDO-co-PCL) was synthesized by ring opening polymerization (ROP) of p-dioxanone and ɛ-caprolactone initiated through the hydroxyl end of poly(ethylene glycol) (PEG) in the presence of stannous 2-ethyl hexanoate [Sn(oct)₂] as a catalyst. Polymerization and structural features of the polymers were analyzed by different physicochemical techniques (GPC, ¹H NMR, ¹³C NMR, FT-IR, DSC and TGA). The splitting of ¹H NMR resonance at δ 2.3 and δ 4.1 ppm reveals the random copolymerization. Polymeric nanoparticles were prepared in phosphate buffer (pH 7.4) by co-solvent evaporation technique at room temperature (25 °C). Existence of hydrophobic domains as cores of the micelles were characterized by ¹H NMR spectroscopy and further confirmed with fluorescence technique using pyrene as a probe. Critical micelle concentration (CMC) of the polymer in phosphate buffer (pH. 7.4) was decreased from 2.3 × 10⁻³ to 7.6 × 10⁻⁴ g/L with the fraction of PCL. Polymeric nanoparticles observed by atomic force microscopy (AFM) were uniform and spherical, with smooth textured of around 50–30 nm diameter. Dynamic light scattering (DLS) and electrophoretic light scattering (ELS) measurements showed a monodisperse size distribution of around 113–90 nm hydrodynamic diameters and negative zeta (ζ) potential (−4 to −14 mV), respectively. The investigations for the polymeric nanoparticles in aqueous medium showed that the composition of the hydrophobic segment of amphiphilic block copolymer makes a significant influence on its physicochemical characteristics.     

Diterpenoids from the aerial parts of Leonurus macranthus

One cis clerodane-type (1) and three highly oxygenated labdane-type diterpenes (2-4) were isolated from the aerial parts of Leonurus macranthus. Compound 1 represents the first example of cis clerodane-type diterpene in the plants of Leonurus genus.     

Polyolefin-functionalized graphene oxide and its GO/HDPE nanocomposite with excellent mechanical properties

An effective strategy for the polyolefin-functionalized graphene oxide (fGO) using two-step methods has been reported for GO/HDPE nanocomposite with excellent mechanical properties.     

The effect of storage duration on bio-oil properties

Bio-oil produced by fluidized fast pyrolysis of yellow poplar wood (Liriodendron tulipifera) was stored in sealed glass bottles at 23 °C for 2, 4, 6, 8, or 10 weeks to investigate the effect of storage time on bio-oil properties. Bio-oil viscosity increased with increasing storage duration, while pH, water content and heating value remained unchanged. Thirty-three components were identified in the bio-oils and were classified into five sub-groups: aldehydes and ketones from carbohydrates, aliphatic phenols, phenolic aldehydes, and phenolic ketones from lignin. The concentrations of the sub-groups, especially the carbohydrate-derived ketones and lignin-derived compounds, gradually decreased with prolonged storage. In contrast, the yield of pyrolytic lignin extracted from bio-oils increased with storage duration from 13.2 wt% (fresh bio-oil; control) to 24.3 wt% (10 weeks). The average molecular weight of pyrolytic lignin also increased from 872 (control) to 1161 g mol⁻¹ (10 weeks). The amounts of phenolic hydroxyl and methoxyl groups decreased from 11.2 wt% (control) to 8.0 wt% (10 weeks) and 11.9 wt% (control) to 8.6 wt% (10 weeks), respectively. The observations strongly indicate that the low molecular weight components could participate in the re-polymerization with pyrolytic lignin, and the plausible polymerization reactions could be predicted to esterification, oxidation, hemiacetal/acetal formation and olefinic condensation.     

A simple method for the synthesis of 4-arylselanyl-7-chloroquinolines used as in vitro acetylcholinesterase inhibitors and in vivo memory improvement

We described here an alternative method for the synthesis of 4-arylselanyl-7-chloroquinolines through reactions of 4,7-dichloroquinoline with organylselenols, generated in situ by the reaction of diorganyl diselenides with H₃PO₂ (50 wt% in H₂O). These reactions proceeded efficiently at 60 °C under N₂ atmosphere and are suitable to a range of diorganyl diselenides containing electron-donating and electron-withdrawing groups, affording the corresponding 4-aryl-7-chloroquinolines in high yields. The synthesized compounds were screened for their in vitro acetylcholinesterase (AChE) activity and our results demonstrated that the 7-chloro-4-[(4-fluorophenyl)selanyl]quinoline inhibited the AChE activity and improved memory in mice, making this compound is a potential therapeutic agent for the treatment of Alzheimer disease and other neurodegenerative disorders.     

Preparation and properties of zirconia nanotube-supported 12-tungstophosphoric acid catalyst

Zirconia nanotube-supported H₃PW₁₂O₄0 (HPW) catalysts exhibit high catalytic activities in the synthesis of fatty acid ethyl ester.     

Novel strategy of constructing fluorescent probe for MAO-B via cascade reaction and its application in imaging MAO-B in human astrocyte

A novel strategy was developed to detect MAO-B and image MAO-B in human astrocyte by constructing coumarin via cascade reaction and intramolecular cyclization.     

Kinetics of the diazotization and azo coupling reactions of procaine in the micellar media

The kinetics of the diazotization reaction of procaine in the presence of anionic micelles of sodium dodecyl sulfate (SDS) and cationic micelles of cetyltrimethyl ammonium bromide (CTAB), dodecyltrimethyl ammonium bromide (DDTAB) and tetradecyltrimethyl ammonium bromide (TDTAB) were carried out spectrophotometrically at λ_max = 289 nm. The values of the pseudo first order rate constant were found to be linearly dependent upon the [NaNO₂] in the concentration range of 1.0 × 10⁻³ mol dm⁻³ to 12.0 × 10⁻³ mol dm⁻³ in the presence of 2.0 × 10⁻² mol dm⁻³ acetic acid. The concentration of procaine was kept constant at 6.50 × 10⁻⁵ mol dm⁻³. The addition of the cationic surfactants increased the reaction rate and gave plateau like curve. The addition of SDS micelles to the reactants initially increased the rate of reaction and gave maximum like curve. The maximum value of the rate constant was found to be 9.44 × 10⁻³ s⁻¹ at 2.00 × 10⁻³ mol dm⁻³ SDS concentration. The azo coupling of diazonium ion with β-naphthol (at λ_max = 488) nm was found to linearly dependent upon [ProcN₂⁺] in the presence of both the cationic micelles (CTAB, DDTAB and TDTAB) and anionic micelles (SDS). Both the cationic and anionic micelles inhibited the rate of reactions. The kinetic results in the presence of micelles are explained using the Berezin pseudophase model. This model was also used to determine the kinetic parameters e.g. k_m, K_s from the observed results of the variation of rate constant at different [surfactants].     

Synthesis,bioactivity, action mode and 3D-QSAR of novel anthranilic diamide derivatives

Several newly synthesized anthranilic diamide derivatives were found to exhibit excellent bioactivity. The action mode test and 3D-QSAR analysis provided valuable information for evaluation and future design of anthranilic diamide insecticides.