Nature nanotechnology最新文献

Excitons are prevalent in many bosonic quantum phenomena in semiconductors. During their optical transitions, excitons not only emit or absorb photons, but also determine light propagation behaviours within the host medium. While absorption and emission processes have found numerous practical applications, chiefly in light-emitting diodes and solar cells, excitons' capability of manipulating light propagation remains largely underexplored. Here we observe negative refraction-light bending in the opposite direction to conventional refraction-in an excitonic van der Waals magnet, namely chromium sulphide bromide (CrSBr). We also develop an excitonic hyperlens on an integrated nanophotonic chip, whose functionality is mediated by the magnetic orders of CrSBr. Specifically, the observed negative refraction and hyperlens effects emerge when CrSBr is magnetically ordered, driven by a magnetic enhancement of excitonic resonances. This work establishes excitons in van der Waals magnets as a versatile platform for controlling anomalous light propagation at the nanoscale.

DNA origami holds great potential for advancing therapeutics, but the lack of methods for the precise assessment of structural integrity in vivo prevents its translation. Here we introduce proximity ligation assay for structural tracking and integrity quantification (PLASTIQ) for resolving origami structural integrity with only 1 µl of blood sample and with a detection limit of 0.01 fM. Through PLASTIQ, we could observe and quantify the dynamics of DNA origami degradation during blood circulation and evaluate the effectiveness of PEGylation for slowing this process in a murine model. Additionally, by using a double-layered barrel-like origami structure, we found distinct degradation kinetics of DNA helices depending on their specific location, revealing the slower degradation of internal helices compared with the outer ones. Our results suggest that PLASTIQ offers a quantitative approach for assessing DNA origami integrity in vivo by longitudinal sampling, providing dynamic pharmaceutical-level insights for accelerating the development of DNA-nanostructure-based therapeutic molecules and drugs.

Intra-articular RNA therapeutics have shown promise in osteoarthritis (OA); however, maximizing their efficacy requires targeted delivery to degenerating cartilage within focal lesions. As OA progresses, cartilage degeneration worsens, necessitating disease-responsive targeting with enhanced delivery in advanced stages. Here we develop an anionic nanoparticle (NP) strategy for targeting glycosaminoglycan loss, a hallmark of OA's progression that reduces cartilage's negative charge. These NPs selectively diffuse and accumulate into matrix regions inversely correlated with glycosaminoglycan content owing to reduced electrostatic repulsion, a strategy we term 'matrix inverse targeting' (MINT). In a mouse model of OA, intra-articular delivery of luciferase messenger RNA-loaded MINT NPs demonstrated disease-severity-responsive expression. Using this strategy, we delivered ghrelin mRNA, as ghrelin has shown chondroprotection properties previously. Ghrelin mRNA-loaded MINT NPs reduced cartilage degeneration, subchondral bone thickening and nociceptive pain. Our findings highlight the potential of ghrelin mRNA delivery as a disease-modifying therapy for OA and the platform's potential for lesion-targeted RNA delivery responsive to disease severity.

Control of charge and heat transport is essential for computing and thermal management technologies. Recent work with superconducting materials has shown rectified electrical supercurrents near liquid helium temperatures. However, despite large theoretical interest and expected impact on quantum technologies, no experiments have demonstrated control of nanoscale radiative heat currents at cryogenic temperatures. Here we study photon-mediated thermal transport in nanogaps between niobium and gold. Using novel scanning calorimetric probes and nanofabricated devices, we reveal a ~20-fold suppression of radiative heat transport, when niobium transitions from the metallic to the superconducting state. Taking advantage of this effect, we also demonstrate a niobium-based cryogenic thermal diode with a heat rectification ratio of 70%. The experimental techniques and advances presented here will enable studying nanoscale thermal transport in quantum materials and advancing thermal management of superconducting devices.

Designed biomolecular condensates are emerging condensed-phase assemblies, initially conceived to mimic cellular biomolecular condensates for use in biology-inspired applications such as delivery and storage of biomolecules. In recent years, rational design approaches informed by supramolecular chemistry and biomolecular nanotechnology, including the use of peptide and DNA nanotechnology for building-block minimalization and site-specific interactions, have evolved rapidly, going beyond the molecular basis of cellular condensates in terms of both composition and functionality. Thus, synthetic condensates are designed from diverse molecular building blocks, including single- or multicomponent polypeptides, peptides, RNA, DNA or biopolymers; moreover, their applications are continuously evolving to encompass new nanotechnology-relevant functions including biosensing and bioadhesion, where condensates offer advantages such as responsiveness, programmability and molecular compartmentalization. In this Review, we show the main concepts behind the molecular design of synthetic condensates, from biological mimicry to purely synthetic approaches. We discuss the mechanisms that allow control and regulation of condensate properties and the remaining challenges in analysing these properties. Finally, we discuss the applications of synthetic condensates thus far, the potential in leveraging condensates as platforms for nanotechnological applications, and the remaining hurdles towards realizing this promise. We also provide an overview of the patent landscape, highlighting trends in commercial development across areas such as delivery systems, microreactors and sensing technologies.