Designed oligonucleotides can self-assemble into DNA nanostructures with well-defined structures and uniform sizes, which provide unprecedented opportunities for biosensing, molecular imaging, and drug delivery. In this work, we have developed functional, multivalent DNA nanostructures by appending unmethylated CpG motifs to three-dimensional DNA tetrahedra. These small-sized functional nanostructures are compact, mechanically stable, and noncytotoxic. We have demonstrated that DNA nanostructures are resistant to nuclease degradation and remain substantially intact in fetal bovine serum and in cells for at least several hours. Significantly, these functional nanostructures can noninvasively and efficiently enter macrophage-like RAW264.7 cells without the aid of transfection agents. After they are uptaken by cells, CpG motifs are recognized by the Toll-like receptor 9 (TLR9) that activates downstream pathways to induce immunostimulatory effects, producing high-level secretion of various pro-inflammatory cytokines including tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-12. We also show that multivalent CpG motifs greatly enhance the immunostimulatory effect of the nanostructures. Given the high efficacy of these functional nanostructures and their noncytotoxic nature, we expect that DNA nanostructures will become a promising tool for targeted drug delivery.

Conjugates of DNA and gold nanoparticles (AuNPs) typically exploit the strong Au-S chemistry to self-assemble thiolated oligonucleotides at AuNPs. However, it remains challenging to precisely control the orientation and conformation of surface-tethered oligonucleotides and finely tune the hybridization ability. We herein report a novel strategy for spatially controlled functionalization of AuNPs with designed diblock oligonucleotides that are free of modifications. We have demonstrated that poly adenine (polyA) can serve as an effective anchoring block for preferential binding with the AuNP surface, and the appended recognition block adopts an upright conformation that favors DNA hybridization. The lateral spacing and surface density of DNA on AuNPs can also be systematically modulated by adjusting the length of the polyA block. Significantly, this diblock oligonucleotide strategy results in DNA-AuNPs nanoconjugates with high and tunable hybridization ability, which form the basis of a rapid plasmonic DNA sensor.

An integrated composite tin sulfide bonded on an amino-functionalized graphene as a novel anode material for NIBs is reported. Tight contact with SnS2nanocrystals and discharge products on the amino-functionalized graphene interface results in excellent electrochemical performance.

Four hemicyanine derivatives, (E)-N- (3-sulfopropyl-4-[2-(4-dimethylaminophenyl) ), have been synthesized and characterized with regard to their absorption and electrochemical properties. Photoelectrochemical experiments show that these hemicyanine dyes with D-π-A systems can yield efficient charge separation under illumination of simulated solar light. Alkyl chain has a remarkable effect on dye adsorbance, incident photon-to-electron conversion efficiency, and overall energy conversion yield. The overall yield is approximately doubled when the methyl group replaces the long alkyl chain. Action spectrum of QS displayed a broad feature with 33.8% of maximum monochromatic incident photon-to-electron conversion efficiency (IPCE), and a thin-layer sandwich-type solar cell based on nanocrystalline TiO 2 film modified with QS produced about 2% of overall yield. For the first time, a photovoltaic liquid-junction solar cell based on nanostructured TiO 2 electrode sensitized by hemicyanine dyes is reported.

Graphene oxide (GO), has created an unprecedented opportunity for development and application in biology, due to its abundant functional groups and well water solubility. Recently, the potential toxicity of GO in the environment and in humans has garnered more and more attention. In this paper, we systematically studied the cytotoxicity of GO nanosheets via examining the effect of GO on the morphology, viability and differentiation of a human neuroblastoma SH-SY5Y cell line, which was an ideal model used to study neuronal disease in vitro. The results suggested that GO had no obvious cytotoxicity at low concentration (<80 μg mL(-1)) for 96 h, but the viability of cells exhibited dose- and time-dependent decreases at high concentration (≥ 80 μg mL(-1)). Moreover, GO did not induce apoptosis. Very interestingly, GO significantly enhanced the differentiation of SH-SY5Y induced-retinoic acid (RA) by evaluating neurite length and the expression of neuronal marker MAP2. These data provide a promising application for neurodegenerative diseases.

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The introduction of GW approximation to the electron's self‐energy by Hedin in the 1960s, where G and W denote the one‐particle Green's function and the screened Coulomb interaction, respectively, facilitates the computation of quasiparticle energies through Dyson's equation. GW method can also help us determine the electron–hole interaction, which is a functional derivative of self‐energy with respect to one‐particle Green's function, with excellent accuracy, and its combination with Bethe–Salpeter equation, which is derived from two‐particle Green's function, is a powerful tool to study electronic excitations and optical absorption. Thanks to the development of methodology and softwares during the last 30 years, the capability of GW method and Bethe–Salpeter equation to deal with real systems is elevated substantially, while they also exhibit many advantages over other first‐principles methods in band structures, ionization potentials, electron affinities, optical spectra, and so on. They have been successfully applied in the excited states of various systems, including crystals, metals, nanomaterials, chemical and biological systems, and so on. WIREs Comput Mol Sci 2016, 6:532–550. doi: 10.1002/wcms.1265 This article is categorized under: Electronic Structure Theory > Ab Initio Electronic Structure Methods Theoretical and Physical Chemistry > Spectroscopy