Highly fluorescent and water-soluble gold nanoclusters (AuNCs) with near-infrared-emission and Au@AgNCs with yellow-emission were successfully prepared via a rapid sonochemical approach, and the as-prepared AuNCs could be applied in the determination of Cu(2+) with a wider detection range and lower detection limit.

The aerolysin nanopore channel is one of the confined spaces for single molecule analysis which displays high spatial and temporal resolution for the discrimination of single nucleotides, identification of DNA base modification, and analyzing the structural transition of DNAs. However, to overcome the challenge of achieving the ultimate goal of the widespread real analytical application, it is urgent to probe the sensing regions of the aerolysin to further improve the sensitivity. In this paper, we explore the sensing regions of the aerolysin nanopore by a series of well-designed mutant nanopore experiments combined with molecular dynamics simulations-based electrostatic analysis. The positively charged lumen-exposed Lys-238, identified as one of the key sensing sites due to the presence of a deep valley in the electrostatic potentials, was replaced by different charged and sized amino acids. The results show that the translocation time of oligonucleotides through the nanopore can be readily modulated by the choice of the target amino acid at the 238 site. In particular, a 7-fold slower translocation at a voltage bias of +120 mV is observed with respect to the wild-type aerolysin, which provides a high resolution for methylated cytosine discrimination. We further determine that both the electrostatic properties and geometrical structure of the aerolysin nanopore are crucial to its sensing ability. These insights open ways for rationally designing the sensing mechanism of the aerolysin nanopore, thus providing a novel paradigm for nanopore sensing.

An ideal network window electrode for photovoltaic applications should provide an optimal surface coverage, a uniform current density into and/or from a substrate, and a minimum of the overall resistance for a given shading ratio. Here we show that metallic networks with quasi-fractal structure provides a near-perfect practical realization of such an ideal electrode. We find that a leaf venation network, which possesses key characteristics of the optimal structure, indeed outperforms other networks. We further show that elements of hierarchal topology, rather than details of the branching geometry, are of primary importance in optimizing the networks, and demonstrate this experimentally on five model artificial hierarchical networks of varied levels of complexity. In addition to these structural effects, networks containing nanowires are shown to acquire transparency exceeding the geometric constraint due to the plasmonic refraction.

Tau phosphorylation shows direct clinical importance as the hyperphosphorylation and aggregation of tau exists in a range of tauopathies. However, it is still challenging to study tau phosphorylation owing to its multiple and adjacent phosphorylation sites in the tau sequence. To address this challenge, here, a designed T232K/K238Q mutant aerolysin nanopore is introduced which synergistically incorporates the enhanced electrostatic interaction at T232K site and the high repelling barrier at K238Q site. The distinct current blockages produced by a T232K/K238Q aerolysin sensor achieve nearly 100% identification accuracy for the characteristic distribution of unphosphorylated tau peptide, pS262‐, pT263‐tau peptide, and pS262/pT263‐tau peptide. The excellent sensing ability of the T232K/K238Q nanopore originates from the extremely slow translocation speed which prolongs the duration up to tens or hundreds milliseconds for a nine‐amino‐acid peptide. It is envisioned that the design ideas of the T232K/K238Q aerolysin nanopore can be further applied to analyze other protein/peptide post‐translational modification as it provides the exquisite sensitivity for identifying the modification of single amino acids.

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