Nature nanotechnology最新文献

Bottom-up synthetic biology seeks to engineer a cell from molecular building blocks. Using DNA nanotechnology, building blocks, such as cytoskeletons, have been reverse-engineered. However, DNA nanostructures rely on chemical synthesis and thermal annealing, and therefore synthetic cells cannot produce them from their constituents such as nucleotides. Here we introduce RNA origami cytoskeleton mimics as alternative nucleic acid-based molecular hardware for synthetic cells, which we express directly inside giant unilamellar lipid vesicles (GUVs) containing a DNA template and a polymerase, chemically fuelled by feeding nucleotides from the outside. We designed RNA origami tiles that fold upon transcription and self-assemble into micrometre-long, three-dimensional RNA origami nanotubes under isothermal conditions. We observe that sequence mutations on the DNA template lead to RNA origami nanotubes and closed-ring phenotypes. Molecular dynamics simulations show that these phenotypic transitions are governed by alterations in the stability of RNA secondary structures. In addition, we achieve cortex formation with aptamer-functionalized RNA nanotubes and show that nanotube polymerization leads to membrane deformation. Altogether, our data suggest that the expression of RNA origami-based hardware will help to explore active, evolvable and RNA-based synthetic cells.

Collective excitations presenting nonlinear dynamics are fundamental phenomena with broad applications. A prime example is nonlinear optics, where diverse frequency-mixing processes are central to communication and attosecond science, and extreme (>sixth-order) harmonic generation provides broad wavelength conversion. Leveraging recent progress in van der Waals magnetic semiconductors, we demonstrate nonlinear optomagnonic coupling. In the layered antiferromagnetic semiconductor CrSBr, we observe exciton states dressed by up to 20 harmonics of magnons, resulting from their extreme nonlinearities. We also create tunable optical sidebands via sum- and difference-frequency generation between two optically bright magnon modes under symmetry-breaking magnetic fields. Moreover, we can tune the observed difference-frequency generation mode into resonance with one of the fundamental magnons, which results in parametric amplification of magnons. Our findings realize the modulation of the optical-frequency exciton with the extreme nonlinearity of magnons at microwave frequencies, which could find applications in magnonics and hybrid quantum systems, and provide a method for optomagnonic neuromorphic computing devices.

Selective production of valuable glycerol chemicals, such as glycerate (which serves as an important chemical intermediate), poses a significant challenge due to the facile cleavage of C–C bonds and the presence of multiple reaction pathways. This challenge is more severe in the electro-oxidation of glycerol, which requires the development of desirable electrocatalysts. To facilitate the glycerol electro-oxidation reaction to glycerate, here we present an approach utilizing a high-entropy PtCuCoNiMn nanosurface. It exhibits exceptional activity (~200 mA cm⁻² at 0.75 V versus a reversible hydrogen electrode) and selectivity (75.2%). In situ vibrational measurements and theoretical calculations reveal that the exceptional glycerol electro-oxidation selectivity and activity can be attributed to the unique characteristics of the high-entropy surface, which effectively modifies the electronic structure of the exposed Pt sites. The catalyst is successfully applied in an electrolyser for long-term glycerol electro-oxidation reaction, demonstrating excellent performance (~200 mA cm⁻² at 1.2V_cell) over 210 h. The present study highlights that tailoring the catalytic sites at the catalyst–electrolyte interface by constructing a high-entropy surface is an effective strategy for electrochemical catalysis.

The electrochemical CO reduction reaction (CORR) has attracted a surge of research interest in sustainably producing high-value multi-carbon products, such as acetate. Nevertheless, most current CORR catalysts exhibit low acetate current densities, poor longevity and limited acetate selectivity. Here we present a Zeolite Socony Mobil-confined Cu single-atom cluster (CuZSM SACL) for CORR, in which Cu SAs are chemically anchored via robust Cu–O–Si bonds while Cu CLs are physically trapped within the porous framework of zeolite cavities. Consequently, the CuZSM SACL-containing membrane electrode assembly enables a remarkable CO-to-acetate current density of 1.8 A cm⁻² with a high acetate Faraday efficiency of 71 ± 3%. More importantly, we demonstrate that the Cu-based membrane electrode assembly can stably catalyse CO to acetate at an industrial current density of 1 A cm⁻² at 2.7 V (Faraday efficiency 61 ± 5%) beyond 1,000 h at atmospheric pressure. This milestone sheds light on high-performing Cu-type catalysts for practical CORR applications.

The active transport and retention principle is an alternative mechanism to the enhanced permeability and retention effect for explaining nanoparticle tumour delivery. It postulates that nanoparticles actively transport across tumour endothelial cells instead of passively moving through gaps between these cells. How nanoparticles transport across tumour endothelial cells remains unknown. Here we show that nanoparticles cross tumour endothelial cells predominantly using the non-receptor-based macropinocytosis pathway. We discovered that tumour endothelial cell membrane ruffles capture circulating nanoparticles, internalize them in intracellular vesicles and release them into the tumour interstitium. Tumour endothelial cells have a higher membrane ruffle density than healthy endothelium, which may partially explain the elevated nanoparticle tumour accumulation. Receptor-based endocytosis pathways such as clathrin-mediated endocytosis contribute to nanoparticle transport to a lesser extent. Nanoparticle size determines the degree of contribution for each pathway. Elucidating the nanoparticle transport mechanism is crucial for developing strategies to control nanoparticle tumour delivery.

Characterizing quantum states of the electromagnetic field at microwave frequencies requires fast and sensitive detectors that can simultaneously probe the field’s time-dependent amplitude and its quantum fluctuations. So far, this has been achieved by using either homodyne detection or fast digitizers. Both methods rely on the extraction of microwave radiation through an amplification chain towards the detector placed at room temperature, thereby limiting the time resolution to the ~10-GHz bandwidth of the measurement chain. Additionally, the coupling of high-impedance samples to the 50-Ω measurement chain is very weak, setting strong limitations on the detection sensitivity. In this work, we demonstrate an on-chip quantum sensor that exploits the phase of a single-electron wavefunction, measured in an electronic Fabry–Pérot interferometer, to detect the amplitude of a classical time-dependent electric field. The interferometer is implemented in a GaAs/AlGaAs quantum Hall conductor. The time resolution, limited by the temporal width of the electronic wavepacket, is ~35 ps. The interferometry technique provides a voltage resolution of ~50 μV, corresponding to a few microwave photons. Importantly, our detector measures both phase and contrast of the interference pattern. The latter opens the way to the detection of non-classical electromagnetic fields, such as squeezed or Fock states.

An interface between microwave and optical photons offers the potential to network remote superconducting quantum processors. To preserve fragile quantum states, a microwave-to-optical transducer must operate efficiently in the quantum-enabled regime by generating less than one photon of noise referred to its input. Here we achieve these criteria using an integrated electro-optomechanical device made from crystalline silicon. Our platform eliminates the need for heterogeneous integration with piezoelectric materials by utilizing electrostatic actuation of gigahertz-frequency nanomechanical oscillators. Leveraging the ultra-low mechanical dissipation in silicon, our microwave-to-optical transducers achieve below one photon of input-referred added noise (n_add = 0.58) under continuous-wave laser drives. This demonstration of continuous quantum-enabled microwave-to-optical transduction improves the upconversion rate by about two orders of magnitude beyond the state of the art (R = 0.47–1.9 kHz). The increased transduction rate and scalable fabrication of our devices may facilitate near-term use of transducers in distributed quantum computers and quantum networks.