ACS Applied Nano Materials最新文献

As a highly malignant tumor, melanoma is associated with poor prognosis and high recurrence rates. Despite advances in surgery, radiotherapy, chemotherapy, and immunotherapy, drug resistance and immune evasion remain major obstacles. Epigenetic dysregulationsuch as aberrant DNA methylation and histone deacetylationplays a pivotal role in melanoma progression by silencing tumor suppressor genes and promoting immune escape. Although epigenetic therapies have shown promise, single-target strategies often lead to limited efficacy and acquired resistance. Moreover, emerging evidence suggests that cuproptosis, a copper-triggered, mitochondria-dependent cell death modality, is an effective immunogenic mechanism that synergizes with epigenetic reprogramming. Here, we designed a tumor microenvironment-responsive nanosystem (SAHA-CaCO₃@DMY-Cu), which can combine dual epigenetic modulation with cuproptosis to overcome tumor immunosuppression. This nanosystem can simultaneously deliver the histone deacetylation inhibitor vorinostat (SAHA) and the DNA methylation inhibitor dihydromyricetin (DMY) and release copper ions to trigger cuproptosis. This nanosystem achieved an 80.7% reduction in tumor growth and triggered a strong immune activation effect, significantly promoting the maturation of dendritic cells and the intratumoral infiltration of CD4⁺ and CD8⁺T cells while reducing Treg cells. Transcriptomics analysis confirmed the enrichment of immune-related pathways (for example, the cytokine−cytokine receptor interactions and the TNF signaling pathway) as well as ribosome generation, thereby verifying the dual epigenetic regulation−cuproptosis mechanism. This study demonstrates that the constructed nanosystem can overcome tumor immune evasion, thereby providing a “trinity” model (epigenetic reprogramming, cuproptosis, and immune activation) for enhancing immunotherapy for melanoma, which also provides a valuable paradigm for the treatment of other tumors.

Herein, Na⁺-intercalated Ti₃C₂T_x MXene/poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)) Nanofiber (NMN) composite gas sensor was fabricated through systematic surface and structural engineering strategies to achieve enhanced NO₂ sensing performance at room temperature. NaOH treatment of Ti₃C₂T_x MXene simultaneously facilitated the replacement of −F surface terminations with O-containing species, resulting in a higher density of O-containing species that serve as active adsorption sites for NO₂ molecules, and expanded the interlayer spacing of the MXene sheets through Na⁺ intercalation, thereby enlarging the physical accessible surface area for NO₂ adsorption. Specifically, Na⁺-intercalation increased the basal d-spacing of Ti₃C₂T_x from 1.064 to 1.162 nm, demonstrating nanoscale expansion of the layered MXene structure. The functionalized MXene nanosheets are assembled onto electrospun P(VDF-TrFE) nanofibers via dip-coating to further increase surface-to-volume ratio through the three-dimensional porous structure. In this process, the cetyltrimethylammonium bromide (CTAB) is optimized to impart a positive surface charge to the P(VDF-TrFE) nanofibers, thereby enabling robust electrostatic interaction of the negatively charged MXene nanosheets onto the P(VDF-TrFE) nanofiber surface. As a result of these synergistic strategies, the fabricated NMN sensor successfully demonstrated reliable NO₂ detection at a concentration as low as 500 ppb at room temperature with a 45.9-fold higher response than its pristine MXene. Furthermore, the sensor exhibited outstanding NO₂ selectivity over interfering gases, confirming that the proposed surface and structural engineering optimized the NMN sensor for NO₂ detection.

Nanojoining of one-dimensional metal-oxide nanostructures remains challenging because their high melting temperatures and intrinsic brittleness hinder reliable integration into nanoscale electronic systems. Here, we present a two-step femtosecond-laser strategy for predominantly solid-state nanojoining of CuO nanowires through nonequilibrium defect engineering followed by shock-assisted mechanical activation. In the first step, femtosecond-laser pretreatment increases the oxygen-vacancy-related defect density, as supported by XPS measurements, which is associated with lattice softening and enhanced nanoscale plasticity. Quantitative nanoindentation shows corresponding reductions in elastic modulus and hardness, together with an increase in the H/P_y ratio from approximately 2.2 to 3.1, indicating a transition toward a more plastic deformation response. In the second step, femtosecond-laser shock peening under the optimized condition generates transient compressive loading that promotes intimate inter-nanowire contact and interfacial bonding. TEM, HRTEM, localized FFT, and SAED analyses of X-type, Y-type, and end-to-end junctions reveal direct atomic-scale contact, preservation of the monoclinic CuO structure, and no observable thick amorphous interlayer, melt−resolidification morphology, or bulk phase transformation. Single-junction electrical measurements further show a current enhancement of up to approximately 35% after optimized shock peening, demonstrating improved electrical transport across the formed junctions. These results establish a vacancy-assisted, shock-mediated solid-state route for integrating brittle CuO nanowires into conductive nanoscale architectures and electronic interconnects.

Over the years, magnetic nanoparticles (MNPs) have evolved from passive imaging and delivery agents into active transducers that convert externally applied magnetic fields into localized biological stimuli. This transition has created opportunities for magnetogenetics, in which MNPs serve as remotely controlled biointerfaces for regulating cellular activity, tissue function, and therapeutic responses. In this review, we discuss MNP transducers for magnetogenetics from the perspective of materials design, biointerface engineering, and transduction mechanisms. We start with magnetothermal transduction, where nanoparticles dissipate heat under alternating magnetic fields (AMFs) to activate thermosensitive ion channels such as TRPV1, enabling wireless neuronal activation, deep brain stimulation (DBS), regenerative signaling, and disease therapy. We then discuss magnetomechanical transduction, where nanoparticles, nano/micro-discs, nanochains, etc., generate forces, torques, oscillations, or matrix deformation to activate mechanosensitive channels, integrin-mediated pathways, stem cell differentiation, immune modulation, and tumor inhibition. Next, we examine magnetoelectric transduction, where magnetostrictive-piezoelectric materials convert magnetic inputs into local electric fields or surface potentials for neural stimulation, DBS, nerve regeneration, and wound healing. Across these modalities, biological outcomes are governed by intrinsic magnetic properties and several other factors, including particle geometry, anisotropy, surface chemistry, protein corona formation, tissue retention, field waveform, and proximity to the biological target. We further comment on key design principles, including mechanism-specific dosimetry, geometry-field co-design, biointerface localization, targeting specificity, clearance, and chronic safety. Finally, we highlight opportunities for purpose-built, programmable, and closed-loop magnetic biointerfaces that integrate material architecture, magnetic-field input, and biological target selection for precise control of cellular and tissue function.

Conventional static thermal management materials incur overcooling penalties in cold seasons. In this study, we develop a cellulose acetate-based Janus bilayer membrane that enables on-demand switching between radiative cooling and solar heating via mechanical flipping. Fabricated through a scalable non-solvent-induced phase separation and lamination strategy employing bio-renewable materials, the membrane integrates a BaSO₄ cooling side (97.1% solar reflectance, 96.5% mid-infrared emissivity) and an activated carbon heating side (94.0% solar absorptance). multiscale simulationsMie scattering, finite-difference time-domain (FDTD), and COMSOL phase-field and heat-transfer modelingreveal the underlying mechanisms of resonant scattering and hierarchical light-trapping absorption. The dual-mode performance is systematically validated through outdoor ice-melting experiments and small-scale building model tests under real sunlight and xenon-lamp irradiation; in the latter, the two sides maintain a stable 12 °C temperature differential on the same roof. Durability tests confirm >95% optical retention after 1000 abrasion cycles and <4% loss after UV aging. EnergyPlus simulations covering all 34 provincial-level administrative divisions in China demonstrate average cooling and heating energy savings of 68.2% and 39.8%, respectively. This work offers a sustainable, durable, and practically viable solution for year-round building energy conservation.

Multimetallic nanoparticle catalysts present exciting opportunities to achieve sustainable chemical transformations based on their unique structure that can lead to enhanced reactivity, especially when a blend of functional metal atoms is incorporated. The fundamental science regarding the interaction between the metal types and the role of the surface ligands is developing, especially as the number of constituent atom types increases. To investigate these effects, a set of three different bimetallic nanoparticles were prepared (PdAu, AuAg, and PdAg) using the same peptide capping agent (the AuBP1 peptide). Simplified bimetallic materials were probed with a similar interfacial ligand to explore the effect of switching metal composition on catalytic activity, as well as the breadth of compositions that could be prepared using the same peptide ligand. Characterization of the stable structures indicated that bimetallic alloy nanocatalysts were generated with sizes of less than 5 nm in diameter. Catalytic analysis for the reduction of 4-nitrophenol revealed enhanced reactivity for nanoparticles prepared with PdAu and AuAg at metal/metal ratios of 3:2 and 4:1, respectively. These results demonstrate key structural and compositional effects in the materials, which could be used to design different particles of increased complexity for further reactivity enhancement.

Nitrogen-doped carbon nanotube cups (NCNCs) exhibited significant potential as drug carriers owing to their unique cup-shaped and hollow nanostructures. To improve the biocompatibility of individual NCNCs, this study employed a bath sonicator and performed a methodical examination of ultrasonic frequency to optimize oxidation and separation efficiency. The NCNCs were further decorated with iron oxide nanoparticles (Fe₃O₄-NPs) via a co-precipitation method to impart magnetic property to this NCNC-based composite. The biocompatibility of Fe₃O₄-NCNCs was further confirmed by exposing the composites to hydrogen peroxide (H₂O₂), triggering the Fenton reaction to achieve degradation. Ultimately, the practicality of Fe₃O₄-NCNCs as drug delivery carriers was demonstrated by loading the nanocomposites with the ferroptosis inducer RSL3. The in vitro experimental results indicated that the drug-loaded Fe₃O₄-NCNCs have considerable anti-tumor activity, suggesting Fe₃O₄-NCNC as a superior drug delivery platform.

Single-walled carbon nanotubes (SWCNTs) are anisotropic nanoparticles with unique mechanical, electrical, and optical properties. These properties have enabled applications in reinforcing nanocomposites, drug delivery, biosensing, and biomedical imaging, where their performance depends on transport through complex fluids. The mechanisms governing SWCNT transport in structured heterogeneous fluids, however, remain poorly understood because of their multiple characteristic length scales that can be smaller than or comparable to the structural length scales of the surrounding fluid. Here, we investigate the dynamics of SWCNTs in semidilute poly(ethylene oxide) solutions by systematically varying polymer concentration and molecular weight. We directly compare their transport with that of spherical nanoparticles (SNPs) with comparable characteristic dimensions to isolate the effect of particle anisotropy. SWCNTs exhibit substantially enhanced diffusivities up to 300× faster than Stokes−Einstein predictions. These deviations emerge at lower polymer molecular weights and are considerably larger than those observed for SNPs. SWCNT dynamics collapse onto a single curve when plotted as a function of the ratio of nanotube length to the polymer correlation length even well into the entangled regime, whereas SNPs exhibit a steeper power-law decrease that reflects coupling to entanglement dynamics. Moreover, SWCNTs exhibit pronounced non-Gaussian distributions of particle displacements, which confirm that SWCNTs experience different viscosities when transporting along or perpendicular to their length. Our results show that the nanoscale diameter of SWCNTs enables them to avoid constraints imposed by the polymer network and that their anisotropic geometry gives rise to distinct coupling to polymer microstructure and multiple diffusive modes. These findings reveal the mechanisms governing enhanced SWCNT transport and non-Gaussian statistics in structured complex media and provide a framework for predicting SWCNT dynamics in soft matter and biological environments.

Metal−organic frameworks (MOFs) are a highly tunable class of porous materials with potential in various applications. One promising area of research is water adsorption, but challenges remain related to stability and control over water uptake properties. In this study, we report the synthesis of NU-2020, which is structurally analogous to MIL-101 but incorporates a ditopic three-dimensional linker (3DL), bicyclo[2.2.2]octane-1,4-dicarboxylic acid (BODCA), with a sterically bulky and higher symmetry core. We investigated how incorporating a 3DL affects both the stability and water adsorption capacity of MIL-101. The incorporation of BODCA is expected to uniformly decrease pore sizes and increase pore hydrophobicity due to increased linker protrusion into the pore space and the presence of additional hydrophobic carbon and hydrogen atoms. These two modifications to the pores are competing effects that drive the relative humidity at which water uptake occurs in different directions. Decreasing the pore sizes is expected to shift the adsorption step to lower relative humidity, and increasing hydrophobicity is expected to shift the step to higher relative humidity. We employed a combination of thermogravimetric analysis, variable-temperature X-ray diffraction, and porosity measurements to characterize the thermal stability of MIL-101 and NU-2020 and evaluated the water uptake properties through a combination of standardized accelerated aging, contact angle measurements, and water sorption isotherms. Our findings indicate that incorporating a 3DL increases the framework’s thermal stability and increases the water adsorption capacity in NU-2020 relative to MIL-101. Moreover, in this system, the two competing effects appear to be negating one another, resulting in minimal shifts in the water isotherm steps.

HfO₂-based dielectrics engineered into an MPB-like regime have emerged as promising candidates for next-generation dynamic random-access memory (DRAM) capacitors because they offer enhanced dielectric permittivity while preserving the wide bandgap and CMOS compatibility of fluorite-structured oxides. At the nanometer-scale film thicknesses and grain dimensions relevant to DRAM, surface and interface energies, electrode confinement, stress, and defect distributions strongly reshape the relative stability and accessibility of fluorite-derived phases. However, the physical origin of the high-k response and its relationship with leakage current and reliability remain under active discussion. In this review, we summarize recent progress in HfO₂-based MPB dielectrics from three perspectives. First, we discuss two complementary interpretations of dielectric enhancement: spatial phase coexistence between orthorhombic and tetragonal phases at the MPB, and dynamic nonlinear dielectric response associated with low transition barriers and field-induced structural evolution. Second, we review major engineering strategies for achieving MPB-like behavior, including stoichiometric and oxygen-vacancy control, advanced annealing processes, doping, bilayer and superlattice heterostructures, and electrode/interface engineering. Third, we evaluate the practical performance and reliability requirements for DRAM applications, with emphasis on the coupled trade-offs among dielectric constant, leakage current, equivalent oxide thickness, and time-dependent dielectric breakdown. Representative reports include k ≈ 67 with a leakage current density of 3 × 10⁻⁸ A/cm² at 0.8 V and, in a separate ultrathin HZO device, an EOT of approximately 2.42 Å with k ≈ 64.24. Finally, we highlight that the optimization of MPB HfO₂-based dielectrics requires a holistic design framework that simultaneously considers phase stability, defect dynamics, interface quality, and realistic low-voltage benchmarking conditions.