ACS Nano最新文献

Metal oxides are widely used in heterogeneous catalysis as supports to disperse catalytically active nanoparticles, isolated atomic sites, or even as catalysts themselves. Herein, we present a method to produce optically active metal oxide supports that exhibit size-dependent Mie resonances based on TiO₂ nanospheres with tunable size, crystalline phase composition, and optical properties. Mie resonant TiO₂ nanospheres were used as supports to disperse Au, Pt, and Pd nanoparticles. We have found up to a 50-fold enhancement of the electric field at the metal oxide/metal interface corresponding to wavelength-dependent multipolar resonances in the TiO₂ structure. Using Au/TiO₂ as a prototypical photocatalyst, we demonstrate broadband rate enhancements between 400 and 800 nm during CO oxidation, with a noticeable increase below 500 nm. This increased reactivity at higher photon energies is due to improved photon utilization and interband absorption in the gold that results in greater secondary electron generation through electron-electron scattering processes, thus leading to higher rates in conjunction with the Mie scattering TiO₂ support. This study not only highlights the potential of Mie resonant TiO₂ in broadband photocatalytic enhancements but also for developing various Mie resonant metal oxide supports, such as ZnO or Cu₂O, which can improve photocatalytic performance for a number of critical reactions. As the chemical and energy industries move toward conversion technologies driven by renewable energy sources, the strategy of designing optical resonances into oxide supports that are already widely used could enable a straightforward adaptation of photochemical processing based on traditional heterogeneous catalysts.

Facing the challenge of information security in the current era of information technology, optical encryption based on metasurfaces presents a promising solution to this issue. However, most metasurface-based encryption techniques rely on limited decoding keys and struggle to achieve multidimensional complex encryption. It hinders the progress of optical storage capacity and puts encryption security at a disclosing risk. Here, we propose and experimentally demonstrate a multidimensional encryption system based on chip-integrated metasurfaces that successfully incorporates the simultaneous manipulation of three-dimensional optical parameters, including wavelength, direction, and polarization. Hence, up to eight-channel augmented reality (AR) holograms are concealed by near- and far-field fused encryption, which can only be extracted by correctly providing the three-dimensional decoding keys and then vividly exhibit to the authorizer with low crosstalk, high definition, and no zero-order speckle noise. We envision that the miniature chip-integrated metasurface strategy for multidimensional encryption functionalities promises a feasible route toward the encryption capacity and information security enhancement of the anticounterfeiting performance and optically cryptographic storage.

Lead chalcogenide colloidal quantum dots are one of the most promising materials to revolutionize the field of short-wavelength infrared optoelectronics due to their bandgap tunability and strong absorption. By self-assembling these quantum dots into ordered superlattices, mobilities approaching those of the bulk counterparts can be achieved while still retaining their original optical properties. The recent literature focused mostly on PbSe-based superlattices, but PbS quantum dots have several advantages, including higher stability. In this work, we demonstrate highly ordered 3D superlattices of PbS quantum dots with tunable thickness up to 200 nm and high coherent ordering, both in-plane and along the thickness. We show that we can successfully exchange the ligands throughout the film without compromising the ordering. The superlattices as the active material of an ion gel-gated field-effect transistor achieve electron mobilities up to 220 cm² V^-1 s^-1. To further improve the device performance, we performed a postdeposition passivation with PbI₂, which noticeably reduced the subthreshold swing making it reach the Boltzmann limit. We believe this is an important proof of concept showing that it is possible to overcome the problem of high trap densities in quantum dot superlattices enabling their application in optoelectronic devices.

Chronic wound rescue is critical for diabetic patients but is challenging to achieve with a specific and long-term strategy. The prolonged bacterial inflammation is particularly prevalent in hyperglycemia-induced wounds, usually leading to severe tissue damage. Such a trend could further suffer from an environmental suitability provided by macrophages for persisting Staphylococcus aureus (S. aureus) and even deteriorate by their mutual reinforcement. However, the strategy of both suppressing bacteria growth and immunoreprogramming the inflammatory type of macrophages to break their vicious harm to wound healing is still lacking. Here, a self-adapting biomass carboxymethyl chitosan (CMC) hydrogel comprising immunomodulatory nanoparticles is reported to achieve Gram-negative/Gram-positive bacteria elimination and anti-inflammatory cytokines induction to ameliorate the cutaneous microenvironment. Mechanistically, antibacterial peptides and CMCs synergistically result in a long-term inhibition against methicillin-resistant S. aureus (MRSA) over a period of 7 days, and miR-301a reprograms the M2 macrophage via the PTEN/PI3Kγ/mTOR signaling pathway, consequently mitigating inflammation and promoting angiogenesis for diabetic wound healing in rats. In this vein, immunoregulatory hydrogel is a promising all-biomass dressing ensuring biocompatibility, providing a perspective to regenerate cutaneous damaged tissue, and repairing chronic wounds on skin.

Sequential infiltration synthesis (SIS), also known as vapor phase infiltration (VPI), is a quickly expanding technique that allows growth of inorganic materials within polymers from vapor phase precursors. With an increasing materials library, which encompasses numerous organometallic precursors and polymer chemistries, and an expanding application space, the importance of understanding the mechanisms that govern SIS growth is ever increasing. In this work, we studied the growth of polycrystalline ZnO clusters and particles in three representative polymers: poly(methyl methacrylate), SU-8, and polymethacrolein using vapor phase diethyl zinc and water. Utilizing two atomic resolution methods, high-resolution scanning transmission electron microscopy and synchrotron X-ray absorption spectroscopy, we probed the evolution of ZnO nanocrystals size and crystallinity level inside the polymers with advancing cycles─from early nucleation and growth after a single cycle, through the formation of nanometric particles within the films, and to the coalescence of the particles upon polymer removal and thermal treatment. Through in situ Fourier transform infrared spectroscopy and microgravimetry, we highlight the important role of water molecules throughout the process and the polymers' hygroscopic level that leads to the observed differences in growth patterns between the polymers, in terms of particle size, dispersity, and the evolution of crystalline order. These insights expand our understanding of crystalline materials growth within polymers and enable rational design of hybrid materials and polymer-templated inorganic nanostructures.

Rechargeable aqueous batteries adopting Fe-based materials are attracting widespread attention by virtue of high-safety and low-cost. However, the present Fe-based anodes suffer from low electronic/ionic conductivity and unsatisfactory comprehensive performance, which greatly restrict their practicability. Concerning the principle of physical chemistry, fabricating electrodes that could simultaneously achieve ideal thermodynamics and fast kinetics is a promising issue. Herein, hierarchical Fe₃O₄@Fe foam electrode with enhanced interface/grain boundary engineering is fabricated through an in situ self-regulated strategy. The electrode achieves ultrahigh areal capacity of 31.45 mA h cm^-2 (50 mA cm^-2), good scale application potential (742.54 mA h for 25 cm² electrode), satisfied antifluctuation capability, and excellent cycling stability. In/ex situ characterizations further validate the desired thermodynamic and kinetic properties of the electrode endowed with accurate interface regulation, which accounts for salient electrochemical reversibility in a two-stage phase transition and slight energy loss. This work offers a suitable strategy in designing high-performance Fe-based electrodes with comprehensive inherent characteristics for high-safety large-scale energy storage.

The therapeutic efficacy of oncolytic adenoviruses (OAs) relies on efficient viral transduction and replication. However, the limited expression of coxsackie-adenovirus receptors in many tumors, along with the intracellular antiviral signaling, poses significant obstacles to OA infection and oncolysis. Here, we present sonosensitizer-armed OAs (saOAs) that potentiate the antitumor efficacy of oncolytic virotherapy through sonodynamic therapy-augmented virus replication. The saOAs could not only efficiently infect tumor cells via transferrin receptor-mediated endocytosis but also exhibit enhanced viral replication and tumor oncolysis under ultrasound irradiation. We revealed that the sonosensitizer loaded on the viruses induced the generation of ROS within tumor cells, which triggered JNK-mediated autophagy, ultimately leading to the enhanced viral replication. In mouse models of malignant melanoma, the combination of saOAs and sonodynamic therapy elicited a robust antitumor immune response, resulting in significant inhibition of melanoma growth and improved host survival. This work highlights the potential of sonodynamic therapy in enhancing the effectiveness of OAs and provides a promising platform for fully exploiting the antitumor efficacy of oncolytic virotherapy.

Graphite exhibits crystal anisotropy, which impedes the mass transfer of ion intercalation and extraction processes in Li-ion batteries. Herein, a dual-shock chemical strategy has been developed to synthesize the carbon anode. This approach comprised two key phases: (1) a thermal shock utilizing ultrahigh temperature (3228 K) can thermodynamically facilitate graphitization; (2) a mechanical shock (21.64 MPa) disrupting the π-π interactions in the aromatic chains of carbon can result in hybrid-structured carbon composed of crystalline and amorphous carbon. The optimized carbon (DSC-200-0.3) demonstrates a capacity of 208.61 mAh/g at a 10C rate, with a significant enhancement comparing with 15 mAh/g of the original graphite. Impressively, it maintains 81.06% capacity even after 3000 charge-discharge cycles. Dynamic process analysis reveals that this superior rate performance is attributed to a larger interlayer spacing facilitating ion transport comparing with the original graphite, disordered amorphous carbon for additional lithium storage sites, and crystallized carbon for enhanced charge transfer. The dual-shock chemical approach offers a cost-effective and efficient method to rapidly produce hybrid-structured carbon anodes, enabling 10C fast charging capabilities in lithium-ion batteries.

Immunotherapy can potentially suppress the highly aggressive glioblastoma (GBM) by promoting T lymphocyte infiltration. Nevertheless, the immune privilege phenomenon, coupled with the generally low immunogenicity of vaccines, frequently hampers the presence of lymphocytes within brain tumors, particularly in brain tumors. In this study, the membrane-disrupted polymer-wrapped CuS nanoflakes that can penetrate delivery to deep brain tumors via releasing the cell-cell interactions, facilitating the near-infrared II (NIR II) photothermal therapy, and detaining dendritic cells for a self-cascading immunotherapy are developed. By convection-enhanced delivery, membrane-disrupted amphiphilic polymer micelles (poly(methoxypoly(ethylene glycol)-benzoic imine-octadecane, mPEG-b-C18) with CuS nanoflakes enhances tumor permeability and resides in deep brain tumors. Under low-power NIR II irradiation (0.8 W/cm²), the intense heat generated by well-distributed CuS nanoflakes actuates the thermolytic efficacy, facilitating cell apoptosis and the subsequent antigen release. Then, the positively charged polymer after hydrolysis of the benzoic-imine bond serves as an antigen depot, detaining autologous tumor-associated antigens and presenting them to dendritic cells, ensuring sustained immune stimulation. This self-cascading penetrative immunotherapy amplifies the immune response to postoperative brain tumors but also enhances survival outcomes through effective brain immunotherapy.

The advent of catheter-based minimally invasive surgical instruments has provided an effective means of diagnosing and treating human disease. However, conventional medical catheter devices are limited in functionalities, hindering their ability to gather tissue information or perform precise treatment during surgery. Recently, electronic catheters have integrated various sensing and therapeutic technologies through micro/nanoelectronics, expanding their capabilities. As micro/nanoelectronic devices become more miniaturized, flexible, and stable, electronic surgical catheters are evolving from simple tools to multiplexed sensing and theranostics for surgical applications. The review on multifunctional electronic surgical catheters is lacking and thus is not conducive to the reader's comprehensive understanding of the development trend in this field. This review covers the advances in multifunctional electronic catheters for precise and intelligent diagnosis and therapy in minimally invasive surgery. It starts with the summary of clinical minimally invasive surgical instruments, followed by the background of current clinical catheter devices for sensing and therapeutic applications. Next, intelligent electronic catheters with integrated electronic components are reviewed in terms of electronic catheters for diagnosis, therapy, and multifunctional applications. It highlights the present status and development potential of catheter-based minimally invasive surgical devices, while also illustrating several significant challenges that remain to be overcome.