Nature nanotechnology最新文献

Ferroelectric topological textures in oxides exhibit exotic dipole-moment configurations that would be ideal for nonlinear spatial light field manipulation. However, conventional ferroelectric polar topologies are spatially confined to the nanoscale, resulting in a substantial size mismatch with laser modes. Here we report a dome-shaped ferroelectric topology with micrometre-scale lateral dimensions using nanometre-thick freestanding BaTiO₃ membranes and demonstrate its feasibility for spatial light field manipulation. The dome-shaped topology results from a radial flexoelectric field created through anisotropic lattice distortion, which, in turn, generates centre-convergent microdomains. The interaction between the continuous curling of dipoles and light promotes the conversion of circularly polarized waves into vortex light fields through nonlinear spin-to-orbit angular momentum conversion. Further dynamic manipulation of vortex light fields can also be achieved by thermal and electrical switching of the polar topology. Our work highlights the potential for other ferroelectric polar topologies in light field manipulation.

Chemoresistance and immunosuppression are common obstacles to the efficacy of chemo-immunotherapy in colorectal cancer (CRC) and are regulated by mitochondrial chaperone proteins. Here we show that the disruption of the tumour necrosis factor receptor-associated protein 1 (TRAP1) gene, which encodes a mitochondrial chaperone in tumour cells, causes the translocation of cyclophilin D in tumour cells. This process results in the continuous opening of the mitochondrial permeability transition pore, which enhances chemotherapy-induced cell necrosis and promotes immune responses. On the basis of this discovery we developed an oral CRISPR–Cas9 delivery system based on zwitterionic and polysaccharide polymer-coated nanocomplexes that disrupts the TRAP1 gene in CRC. This system penetrates the intestinal mucus layer and undergoes epithelial transcytosis, accumulating in CRC tissues. It enhances chemotherapeutic efficacy by overcoming chemoresistance and activating the tumour immune microenvironment in orthotopic, chemoresistant and spontaneous CRC models, with remarkable synergistic antitumour effects. This oral CRISPR–Cas9 delivery system represents a promising therapeutic strategy for the clinical management of CRC.

Under stress conditions, such as ex vivo culture, chemotherapy, irradiation and infection, haematopoietic stem cells (HSCs) actively divide to maintain blood cell production. This process leads to production of reactive oxygen species (ROS) that causes HSC exhaustion and haematopoietic failure. Here we show that ferumoxytol (FMT; Feraheme), a Food and Drug Administration-approved nanodrug, is a powerful ROS scavenger capable of relieving ROS in stressed HSCs, facilitating their post-injury regeneration. Mechanistically, the catalase-like activity of FMT reduces intracellular levels of H₂O₂ and diminishes H₂O₂-induced cytotoxicity. Moreover, FMT maintains long-term regenerative capacity of transplanted HSCs in pre-conditioned leukaemic mice and shows potential to effectively eliminate leukaemia in vivo while preserving HSCs. Our study highlights FMT as a powerful clinical tool to promote haematopoietic cell recovery in patients undergoing stress-generating treatments.

In the fabrication of FAPbI₃-based perovskite solar cells, Lewis bases play a crucial role in facilitating the formation of the desired photovoltaic α-phase. However, an inherent contradiction exists in their role: they must strongly bind to stabilize the intermediate δ-phase, yet weakly bind for rapid removal to enable phase transition and grain growth. To resolve this conflict, we introduced an on-demand Lewis base molecule formation strategy. This approach utilized Lewis-acid-containing organic salts as synthesis additives, which deprotonated to generate Lewis bases precisely when needed and could be reprotonated back to salts for rapid removal once their role is fulfilled. This method promoted the optimal crystallization of α-phase FAPbI₃ perovskite films, ensuring the uniform vertical distribution of A-site cations, larger grain sizes and fewer voids at buried interfaces. Perovskite solar cells incorporating semicarbazide hydrochloride achieved an efficiency of 26.1%, with a National Renewable Energy Laboratory-certified quasi-steady-state efficiency of 25.33%. These cells retained 96% of their initial efficiency after 1,000 h of operation at 85 °C under maximum power point tracking. Additionally, mini-modules with an aperture area of 11.52 cm² reached an efficiency of 21.47%. This strategy is broadly applicable to all Lewis-acid-containing organic salts with low acid dissociation constants and offers a universal approach to enhance the performance of perovskite solar cells and modules.

The electrosynthesis of pure urea via the co-reduction of CO₂ and N₂ remains challenging. Here we show that a proton-limited environment established in an electrolyser equipped with porous solid-state electrolyte, devoid of an aqueous electrolyte, can suppress the hydrogen evolution reaction and excessive hydrogenation of N₂ to ammonia. This can instead be conducive to the C–N coupling of *CO₂ with *NHNH (the intermediate from the semi-hydrogenation of N₂), thereby facilitating the production of urea. By using nanosheets of an ultrathin two-dimensional metal–azolate framework with cyclic heterotrimetal clusters as catalyst, the Faradaic efficiency of urea production from pretreated flue gas (which contains mainly 85% N₂ and 15% CO₂) is as high as 65.5%, and no ammonia and other liquid products were generated. At a low cell voltage of 2.0 V, the current can reach 100 mA, and the urea production rate is as high as 5.07 g g_cat⁻¹ h⁻¹ or 84.4 mmol g_cat⁻¹ h⁻¹. Notably, it can continuously produce 6.2 wt% pure urea aqueous solution for at least 30 h, and about 1.24 g pure urea solid was obtained. The use of pretreated flue gas as a direct feedstock significantly reduces input costs, and the high reaction rate and selectivity contribute to a reduction in system scale and operational costs.

All-perovskite tandem solar cells (TSCs) offer exceptional performance and versatile applicability. However, a significant challenge persists in bridging the power conversion efficiency (PCE) gap between small- and large-area (>1 cm²) devices, which presents a formidable barrier to the commercialization of all-perovskite TSCs. Here we introduce a specialized crystal-modifying agent, piracetam, tailored for wide-bandgap perovskites, homogenizing top wide-bandgap subcells and enabling the construction of efficient large-area TSCs. Piracetam, featuring amide and pyrrolidone moieties, initially modulates perovskite nucleation, resulting in large-sized grains, preferred (110) orientation, enhanced crystallinity and uniform optoelectronic properties. During the subsequent annealing process, it further eliminates residual PbI₂ and facilitates the formation of one-dimensional (Pi)PbI₃ (Pi = piracetam) perovskite nanoneedles at the grain boundaries and surfaces. Consequently, single-junction 1.77 eV-bandgap solar cells achieve a certified open-circuit voltage of 1.36 V and a PCE of 20.35%. Furthermore, our monolithic two-terminal all-perovskite TSCs, with aperture areas of 0.07 cm² and 1.02 cm², yield PCEs of 28.71% (stabilized 28.55%, certified 28.13%) and 28.20% (stabilized 28.05%, certified 27.30%), respectively, demonstrating a minimal PCE loss of 0.51% when transitioning from small-area to large-area devices. In addition, piracetam demonstrates broad applicability across different perovskite compositions, increasing the PCE from 23.56% to 25.71% for single-junction 1.56 eV-bandgap counterparts. This method thus provides an effective pathway for scalable and efficient all-perovskite TSCs.

Correction to: Nature Nanotechnology https://doi.org/10.1038/s41565-024-01830-y, published online 2 January 2025.

Tin halide perovskites (THPs) have emerged as promising lead-free candidates for eco-friendly perovskite solar cells, but their photovoltaic performance still lags behind that of lead-based counterparts due to poor thin-film quality. Constructing two-dimensional/three-dimensional (2D/3D) heterostructures can effectively regulate crystallization and suppress defect formation for developing high-quality THP thin films. However, the high aggregation barrier prevents large 2D perovskite colloids from forming stable clusters, making 2D THPs nucleate more slowly than their 3D analogues. Such distinct nucleation kinetics cause undesirable 2D/3D phase segregation that compromises both photovoltaic performance and device durability. Here we introduce small inorganic caesium cations to partially replace bulky organic cations in the electrical double layers of 2D THP colloids, reducing the colloid size to lower their aggregation barrier. The reduced electrostatic repulsion promotes the coagulation of 2D and 3D THP colloids in the precursor solution, synchronizing their nucleation kinetics for the growth of 2D/3D heterostructured THP thin films with a homogeneous microstructure and markedly reduced trap states. Consequently, the caesium-incorporated THP solar cells deliver an excellent power conversion efficiency of 17.13% (certified 16.65%) and exhibit stable operation under continuous one-sun illumination for over 1,500 h in nitrogen without encapsulation. This study offers new insights into the colloidal chemistry and crystallization engineering of mixed-dimensional heterostructures, paving the way for high-performance lead-free perovskite photovoltaics.

Nano-enabled catalysis at the interface of metals and semiconductors has found numerous applications, but its role in mediating cellular responses is still largely unexplored. Here we explore the territory by examining the once elusive mechanism through which a nanoporous silicon-based photocatalyst facilitates the two-electron oxidation of water to generate hydrogen peroxide under physiological conditions. We achieve precise modulation of intracellular stress granule formation by the controlled photoelectrochemical production of hydrogen peroxide in the extracellular environment, thereby enhancing cellular resilience to significant oxidative stress. This photoelectrochemical strategy has been evaluated for its efficacy in treating myocardial ischaemia–reperfusion injury in an ex vivo rodent model. Our data suggest that a pretreatment regimen involving photoelectrochemical generation of hydrogen peroxide at mild concentrations mitigates myocardial ischaemia–reperfusion-induced functional decline and infarction. These findings suggest a viable wireless therapeutic intervention for managing ischaemic disease and highlight the biomedical potential of nanostructured semiconductor-based catalytic devices.