Reconfigurable Plasmonic Nanostructures Controlled by DNA Origami

Precise surface functionalization and reconfigurable capability of nanomaterials are essential to construct complex nanostructures with specific functions.Here we show tire assembly of a reconfigurable plasmonic nanostructure,which executes both conformational and plasmonic changes in response to DNA strands.In this work,different sized gold nanoparticles(AuNPs)were arranged site-specifically on the surface of a DNA origami clamp nanostructure.The opening and closing of the DNA origami clamp could be precisely controlled by a series of strand emplacement reactions.Therefore,the patterns of these AuNPs could be switched between two different configura-tions.The observed plasmon band shift indicates the change of the plasmonic interactions among the assembled AuNPs.Our study achieves the construction of reconfigurable nanomaterials with tunable plasmonic interactions,and will enrich the toolbox of DNA-based functional nanomachinery.     

Power spectrum in the MIM waveguide with single tooth-structure and nano-structure detection

The paper proposes the metal–insulator–metal (MIM) waveguides with different tooth-shapes (rectangle-tooth and triangle-tooth) and calculates the corresponding power spectrums by discrete Fourier transform. The finite difference time domain (FDTD) simulation results show that the spectrum transformations reveal the significant differences in the two structures with the same tooth-depth, such as amplitudes, amplitudes difference and spacing of the two peaks. The study will be useful in waveform modulation in the communication wavelength. Furthermore, the spectrum may also be used to detect different nanostructures based on the corresponding transformations.     

The induction of PANoptosis in KRAS-mutant pancreatic ductal adenocarcinoma cells by a multispecific platinum complex

Science China Chemistry - Oncogenic KRAS reprograms pancreatic ductal adenocarcinoma (PDAC) cells to a state that is awfully resistant to apoptosis. An alternative coping strategy is to trigger a...     

Ring-Stacking Water Clusters: Morphology and Stabilities

The structures and interaction energies of water clusters with ring stacking motifs are studied by using ab initio calculations. The structures of the water clusters are constructed by stacking either single rings or multi-rings of tetramer, pentamer, and hexamer. We found that, in the single-ring-stacking motif, the most stable isomers exhibit an alternative clockwise-anticlockwise stacking pattern. We also show that four-layer single-ring-stacking isomers are not energetically favorable in comparison with those of two-layer multi-ring-stacking isomers. The relative stability of the isomers is also analyzed in terms of H-bond strength and elastic distortions of the water molecules.     

Electromechanical coupling dynamics of TBM main drive system

Nonlinear Dynamics - Tunnel boring machine (TBM) is seriously damaged due to excessive vibration, and its anti-vibration design is the key of the drive system design. At present, the coupling model...     

Palladium-catalyzed construction of poly-substituted indolizinones

We have developed a highly efficient one-pot approach to poly-substituted indolizinones from tertiary propargylic alcohols by using a palladium-catalyzed domino reaction. This reaction is proposed to proceed via successive aminopalladation, reductive elimination, and 1,2-shift. While our previous effort to the same skeleton via 2-iodoindolizinones selected α,β-unsaturated esters, terminal acetylenes, or boronic acids as coupling partners, this strategy introduces new functional groups at the C2 position of indolizinone core with (hetero)aryl halides or diallyl carbonate, expanding the substrate scope for decoration at the C2 site. Furthermore, a new preparation route to tertiary propargylic alcohols for this study is described to rapidly diversify the molecular framework.     

An on-chip intestine-liver model for multiple drugs absorption and metabolism behavior simulation

A double-layer microfluidic chip integrated with a hollow fiber(HF)was developed to reconstitute the intestine-liver functionality for studying the absorption and metabolism of combination drugs.Caco-2 cells were inoculated in the HF cavity at the top of the serpentine channel to simulate the intestinal tissue for drug absorption and transport studied,and Hep G2 cells,seeded in the bottom chamber,were used to mimic the liver for metabolism-related studies.Genistein and dacarbazine were selected for combination drug therapy and its effects on cell viability,hepatotoxicity,and cell cycle arrest under drug-conditioned culture were investigated.The results suggested that the combined concentration below-100μg/m L had no significant inhibitory effect on Hep G2 cell viability,and therefore Hep G2 cells maintained their drug metabolism ability.When the drug concentration was increased above 250μg/m L,Hep G2 cells underwent apoptosis.Detection of metabolites by mass spectrometry proved the effective metabolism in the microchip model.This dynamic,co-culture microchip successfully provided a podium for long-term observation of absorption,transport,and metabolism of combination drugs,and could be an effective in vitro simulation model for further clinical research.     

Determination of 2,6-Dichlorophenol by Surface-Enhanced Raman Scattering with Molecular Imprinting

A novel method has been reported for 2,6-dichlorophenol using surface-enhanced Raman scattering (SERS). SiO₂/gold composites were selected as the SERS substrates to provide the response of gold nanoparticles. Molecular imprinting was subsequently used for the development of a specific detector to 2,6-dichlorophenol with precipitation polymerization. The molecularly imprinted polymer provided sensitive and selective SERS detection for the determination of 2,6-dichlorophenol. The intensity and concentration obeyed a linear relationship from 1?×?10^?5 to 1?×?10^?9?mol?L^?1 2,6-dichlorophenol. The sensitivity of SERS with the molecularly imprinted polymers provides a promising approach for practical analysis.     

Phosphine-Functionalized Syndiotactic Polystyrenes: Synthesis and Application to Immobilization of Transition Metal Nanoparticle Catalysts

The precise control of monomer sequence and stereochemistry in copolymerization is of much interest and importance for the synthesis of high performance materials, but studies toward this goal have met with only limited success to date. The coordination polymerization of diphenylphosphinostyrene (p-StPPh₂ and o-StPPh₂) and its copolymerization with styrene (St) by (C₅Me₄SiMe₃)Sc(CH₂C₆H₄NMe₂-o)₂ have been achieved for the first time to afford a new series of phosphine functionalized syndiotactic polystyrene. By the design of the polymer structure, the copolymer of o-StPPh₂ and St (poly(o-StPPh₂-alt-St)-b-sPS) containing o-StPPh₂ and St atactic alternating copolymer block and syndiotactic polystyrene block (sPS) showed excellent thermal stability and chemical resistance. The simple combination of the triphenylphosphine and syndiotactic polystyrene realized the stable immobilization of metal nanoparticles to afford highly robust metal@poly(o-StPPh₂-alt-St)-b-sPS nanocatalysts at high temperature and various atmospheres. The Cu@poly(o-StPPh₂-alt-St)-b-sPS catalyst can serve as a highly efficient heterogeneous catalyst for the synthesis of quinoline derivatives by acceptorless dehydrogenative coupling of o-aminobenzylalcohol with ketones.