Marine mussels harness catechol-rich foot proteins with hierarchically assembled nanostructures to achieve robust adhesion in the dynamic underwater environment.

Optically bright lead halide perovskite nanocrystals of different morphologies ranging from nanocubes to flat nanoplatelets to elongated nanowires have been reported. The morphology of the nanocrystals is expected to affect various properties such as the band edge energy and the electron–hole exchange interaction. However, aside from nanocubes, the investigation of optical properties in the lead halide perovskite nanocrystals of different morphologies at the single emitter level has been lacking. We have performed optical spectroscopy in single CsPbBr3 nanoplatelets and observed single photon emission without blinking. Furthermore, the photoluminescence emission exhibits excitonic fine structure peaks similar to what has been previously observed in nanocubes. Our work stimulates further investigations into the excitonic and quantum optics properties when the lateral size and morphology can be further controlled in lead halide perovskite nanocrystals.

A non-Hermitian topological invariant arising from exceptional points is directly probed in an exciton-polariton system.

Hybrid graphene-PbS quantum dot devices are fabricated on an n-type silicon substrate capped with a thin SiO2 layer and are characterized by photoelectrical measurements. It is shown that the resistance of the graphene channel in the devices exhibits detectable changes when a laser beam is switched on and off on the quantum dots. The model that explains the observed photoresponse phenomenon is illustrated. We also show that the photoresponse signal, i.e., the photoinduced change in the resistance of the graphene channel can be tuned in both magnitude and sign with a voltage applied to the back gate of the devices and is related to the derivative of the transfer characteristics of the graphene channel. Our work shows that the simple hybrid graphene-PbS quantum dot devices can be employed for photodetection applications.

Lead‐free halide double perovskites (A2BIBIIIX6) with attractive optical and electronic features are considered to be a promising candidate to overcome the toxicity and stability issues of lead halide perovskites (APbX3). However, their poor absorption profiles limit device performance. Here the absorption band edge of Cs2AgBiBr6 double perovskite to the near‐infrared range is significantly broadened by developing doped double perovskites, Cs2(Ag:Cu)BiBr6. The partial replacement of Ag ions by Cu ions in the crystal lattice is confirmed by the X‐ray photoelectron spectroscopy (XPS) and solid‐state nuclear magnetic resonance (ssNMR) measurements. Cu doping barely affects the bandgap of Cs2AgBiBr6; instead it introduces subbandgap states with strong absorption to the near‐infrared range. More interestingly, the near‐infrared absorption can generate band carriers upon excitation, as indicated by the photoconductivity measurement. This work sheds new light on the absorption modulation of halide double perovskites for future efficient optoelectronic devices.

With the development of biotechnology, the detection of cancer biomarkers has been a promising approach for cancer diagnosis and therapy. Herein, we reported a DNA octahedron-based fluorescence nanoprobe, which was capable of detecting and imaging of two kinds of tumor-related mRNAs in living cells simultaneously. The DNA nanoprobe was constructed of eight single-stranded DNAs, in which two oligonucleotides (recognition sequences) were modified with quenchers (BHQ2 and BHQ3) and the adjacent sequences were modified with fluorophores (Cy3 and Cy5), respectively. In the presence of targets, the recognition sequences could dissociate from the nanoprobe skeleton by strand displacement reaction and the fluorescence was recovered accordingly. With the modification of AS1411 aptamer, the nanoprobe could internalize cancer cells more efficiently and distinguish cancer cells from normal cells. In addition, the nanoprobe exhibited good stability, biocompatibility, selectivity, and responded quickly to the targets as well. The DNA nanoprobe was designed in the formation of octahedron and may provide an inspiration for multidetection of cancer biomarkers based on the DNA nanotechnology.

Moirésuperlattices of van der Waals structures offer a powerful platform for engineering band structure and quantum states. For instance, Moirésuperlattices in magic-angle twisted bilayer graphene, ABC trilayer graphene have been shown to harbor correlated insulating and superconducting states, while in transition metal dichalcogenide (TMD) twisted bilayers, Moireé xcitons have been identified. Here we show that the effects of a Moireś uperlattice on the band structure are general: In TMD twisted bilayers, excitons and exciton complexes can be trapped in the superlattice in a manner analogous to ultracold bosonic or Fermionic atoms in optical lattices. Using twisted MoSe 2 homobilayers as a model system, we present evidence for Moiret rions.Our results thus open possibilities for designer van der Waals structures hosting arrays of Fermionic or bosonic quasiparticles, which can be used to realize tunable many-body states crucial for quantum simulation and quantum information processing.

Recently there has been a more focus on the development of an efficient technique for detection of circulating tumor cells (CTCs), due to their significance in prognosis and therapy of metastatic cancer. However, it remains a challenge because of the low count of CTCs in the blood. Herein, a rapid and high-sensitivity approach for CTCs detection using an integrated microfluidic system, consisting of a deterministic lateral displacement (DLD) isolating structure, an automatic purifying device with CD45-labeled immunomagnetic beads and a capturing platform coated with rat-tail collagen was reported. We observed high capture rate of 90%, purity of about 50% and viability of more than 90% at the high throughput of 1 mL/min by capturing green fluorescent protein (GFP)-positive cells from blood. Further capturing of CTCs from metastatic cancers patients revealed a positive capture rate of 83.3%. Furthermore, our device was compared with CellSearch system via parallel analysis of 30 cancer patients, to find no significant difference between the capture efficiency of both methods. However, our device displayed advantage in terms of time, sample volume and cost for analysis. Thus, our integrated device with sterile environment and convenient use will be a promising platform for CTCs detection with potential clinical application.