ACS Applied Nano Materials最新文献

The real-time and sensitive monitoring of hydrogen peroxide (H₂O₂) is critically important for predictive analytics and timely intervention in personalized healthcare, particularly for conditions such as diabetes mellitus. Herein, we developed a high-performance dual-mode sensor platform based on exfoliated Co₃O₄ nanosheets (E–Co₃O₄ NSs) for the simultaneous colorimetric and electrochemical detection of H₂O₂. The E–Co₃O₄ NSs induce a hierarchical flower-like structure, which exhibits an exceptionally large surface area (43.8 m²/g) with abundant mesoporous active sites. This unique architecture not only enhances adsorption/desorption kinetics but also significantly decreases the Fermi level, leading to encouraging the overall conductivity. Most importantly, the synthesized catalyst exhibits robust intrinsic peroxidase mimetic activity, facilitating the rapid conversion of colorless TMB to a blue oxidized product, as evidenced by a distinct UV–vis peak at 654 nm. The platform demonstrates excellent colorimetric sensing for H₂O₂ across a wide linear range of 0.1–80 μM with a low limit of detection (LOD) of 0.07 ± 0.05 μM (S/N = 3). Simultaneously, it delivers superior electrochemical performance, with DPV and amperometric measurements showing an identical linear range (0.1–80 μM) with lower LODs (0.08 ± 0.04 and 0.09 ± 0.04 μM) and electrochemical sensitivity of 490.2 μA mM^–1·cm^–2, respectively. In addition, this work displays key analytical advantages including outstanding selectivity, long-term stability, and excellent reproducibility. Most excitingly, the E–Co₃O₄ NSs sensor was successfully applied for the reliable and accurate detection of H₂O₂ in real clinical samples (urine) from diabetic mellitus patients. Thus, the proposed dual-mode E–Co₃O₄ NSs-based detection platforms set a benchmark for simultaneous colorimetric and electrochemical analysis. This work highlights a key prospect for developing highly reliable, cost-effective, and practical diagnostic tools that will significantly boost future clinical applications.

Surface-enhanced Raman spectroscopy (SERS) is a potent, label-free method for highly sensitive molecular detection. We illustrate the ion-beam engineering of MoO₃–Ag–Au multilayer plasmonic substrates to improve SERS performance. Orthorhombic α-MoO₃ microflakes were produced via chemical vapor deposition (CVD) on Si/SiO₂ substrates. Thin films of Ag (5 nm) and Au (5 nm) were thermally evaporated onto the MoO₃ flakes, and the samples were subjected to 100 MeV Ag⁸⁺ swift heavy ion irradiation at fluences of 3 × 10¹¹ and 3 × 10¹² ions/cm². Irradiation causes dewetting of metal films, prompting structural and morphological changes that result in the formation of dispersed Ag–Au nanoparticles, enhanced surface roughness, and defect generation within the MoO₃ lattice. X-ray diffraction (XRD) verifies the α-MoO₃ phase; field emission scanning electron microscopy (FESEM) elucidates nanoparticle formation and surface reorganization; Raman spectroscopy and X-ray photoelectron spectroscopy (XPS) disclose vibrational alterations and binding-energy shifts in Mo 3d, indicative of oxygen vacancies (V_O) and partial reduction of Mo. SERS measurements of molecular probes demonstrate significantly increased Raman intensities following ion irradiation. Finite-difference time-domain (FDTD) simulations assess localized surface plasmon resonance (LSPR) and near-field enhancement linked to the nanoparticle–flake configuration, while density functional theory (DFT) calculations of the electronic structure and density of states (DOS) validate the involvement of V_O in facilitating charge-transfer interactions. Experimental and theoretical evidence suggests that targeted swift-ion irradiation adjusts both electromagnetic and chemical enhancement mechanisms in MoO₃–Ag–Au multilayer nanostructures, offering a reliable method for creating tunable, high-performance SERS substrates for ultrasensitive molecular detection.

InAs_xP_1–x quantum dots (QDs) embedded in InP nanowires (NWs) have recently emerged as a promising platform, offering good control over QD size, composition, and density through Au-catalyzed vapor–liquid–solid (VLS) growth. A unique advantage of this approach is the possibility of directly growing a waveguide around the QD, exploiting precise control of NW radial growth. Usually, InAs_xP_1–x NW-QDs are grown along the <111> direction with a wurtzite (WZ) crystal phase, where waveguides are typically realized using selective-area epitaxy combined with VLS (SAE-VLS), requiring preparation and prepatterning of the substrates. In the case of growth along the <100> direction, the growth of defect-free zincblende InAs_xP_1–x NW-QDs occurs at larger catalyst nanoparticle diameter compared to the WZ counterpart, with tunable emission over the telecom bands. Here, we show that in this system, efficient InP waveguides can be realized around the QDs without the need for SAE-VLS, solely by balancing axial and radial growth contributions during the NW growth. Employing the finite-difference time-domain simulations to optimize the NW-QD geometries allows us to experimentally investigate the interrelation between the growth parameters and the waveguide morphology. Microphotoluminescence measurements of the optimized structures confirm their improved emission properties and one order of magnitude enhanced QD emission intensity in the telecom range.

All-inorganic metal halide (IMH) perovskite and semiconductor core–shell nanomaterials have attracted attention as optoelectronic materials due to their potential to improve both the lifetimes and device functionality. However, the ligands used to synthesize IMH nanostructures stabilize the IMH but also introduce an insulating layer at the interface, which may hinder carrier transport. Herein, we report a ligand-free in situ synthesis of CsPbBr₃/TiO₂ core–shell nanofibers using hollow TiO₂ nanofibers (HTNFs) fabricated via electrospinning as templates. The resulting one-dimensional (1D) heterostructures exhibit a uniform morphology, with CsPbBr₃ confined within the hollow core and encapsulated by a protective TiO₂ shell. This architecture enhances the photostability of the perovskite and facilitates efficient carrier transfer from the CsPbBr₃ core to the TiO₂ shell, resulting in a 1.8-fold increase in photocatalytic activity for the degradation of 2-mercaptobenzothiazole as compared to pristine HTNFs. Our approach offers a strategy for fabricating stable perovskite-based heterostructures without the need for organic surface ligands, making it highly attractive for next-generation photonic and photocatalytic devices.

Conventional cancer treatments have shown limited efficacy and substantial side effects, often allowing cancer cells to survive during treatment. To address these challenges, more recent therapeutic approaches have focused on targeting cancer-specific metabolic pathways. Cancer cells exhibit a metabolic shift toward aerobic glycolysis for energy production, even under oxygen-rich conditions, which is a hallmark known as the Warburg effect. Liver cancer exhibits rapid metabolic activity with a strong dependence on both glycolysis and oxidative phosphorylation (OXPHOS). Although glycolysis inhibition has been explored, metabolic compensation via the adsorption of OXPHOS often undermines therapeutic efficacy. To overcome this limitation, we developed a nanoscale dual-metabolic inhibition platform using PEGylated PLGA (PLGA-PEG) nanoparticles to encapsulate shikonin (SHK; glycolysis inhibitor) or atovaquone (ATO; OXPHOS inhibitor) via a double-emulsion solvent evaporation method. The resulting uniformly dispersed nanoparticles exhibit enhanced solubility, stability, and tumor accumulation through the enhanced permeability and retention (EPR) effect. Separate nanoencapsulation enabled precise control of the SHK:ATO ratio, which was optimized for selective cytotoxicity toward HepG2 cells while minimizing toxicity to normal fibroblasts. In vitro, the combination disrupted glycolytic and mitochondrial metabolism and induced apoptosis. Building on these results, in vivo studies using an orthotopic HCC model confirmed efficient tumor accumulation, marked tumor suppression, and reduced liver toxicity. This study presents a nanoparticle-enabled dual metabolic inhibition strategy that achieves potent antitumor efficacy while overcoming the limitations of conventional cancer therapies and single-pathway metabolic inhibitors, offering a promising nanomedicine approach for HCC.

The development of printable smart windows requires optimizing ink compositions that incorporate electrochromic nanoparticles to meet multiple, often conflicting, performance criteria. Although ink composition is the primary parameter we intentionally vary, such variation is linked to changes in several interconnected factors that cannot be directly controlled or fully observed; these can influence how effectively the nanoscale electrochromic particles exhibit their intrinsic properties. Emerging data-driven approaches offer a promising route for optimizing ink compositions, but their effectiveness decreases under information-sparse conditions, in which important factors influencing performance are lacking in the explicit inputs, thus requiring large sample sizes to statistically recover the missing relationships. Herein, we propose a data-driven framework that remains effective under small-data set conditions and demonstrate its applicability through the optimization of ink compositions containing tungsten oxide nanoparticles, a well-known electrochromic material, even with fewer than 15 experimental samples. By integrating the QBoost model─an annealing-based boosting model─with a carefully preprocessed data set, we achieved high predictive accuracy (R² ≈ 0.9) for key electrochromic property indicators, including coloration efficiency, optical contrast, and response time. The trained model further suggests specific ink compositions expected to achieve balanced improvements across multiple electrochromic properties, offering practical guidance for subsequent experimentation.

The effect of metal doping and transforming from rigid to flexible substrate engineering provides an effective method for customizing the nonlinear optical response of ZnO-based nanostructures. In this study, pristine and Al-doped ZnO thin films and Zr-doped ZnO nanorods (ZnONRs) were synthesized on soda-lime glass and poly(dimethylsiloxane) PDMS substrates using RF magnetron sputtering and Hydrothermal growth methods. The incorporation of Zr dopant results in substantial alterations to the defect and electronic structures of ZnO, consequently leading to a notable enhancement in two-photon absorption and optical limiting responses in comparison to undoped nanorods. Zr-ZnONRs/PDMS demonstrated the highest TPA coefficient (2.61 × 10^–6 m/W) at an intensity of 16.4 MW/cm². The optical limiting threshold of Zr-ZnONR/PDMS was determined to be 1.49 mJ/cm² at an input intensity of 16.4 MW/cm². Structures supported by PDMS exhibit enhanced nonlinear absorption, attributed to defect-supported carrier dynamics and enhanced light-matter coupling at the flexible interface. These results highlight the synergistic effect of Zr doping and the PDMS medium in enhancing nonlinear optical performance, underscoring the potential of doped ZnO nanorods as efficient and cost-effective materials for optical limiting and compact photonic safety device applications in the visible range.

Brønsted and Lewis acid sites (LAS) are the fundamental active centers in heterogeneous catalysis, playing distinct yet complementary roles in driving catalytic reactions. Together, they govern the catalyst’s reactivity and selectivity by enabling multiple reaction pathways. While significant advances have been made in developing experimental methods for the quantitative analysis of acid sites, several challenges remain unresolved. These include: (a) the inability to directly observe the micro- to nanoscale structure of acidic sites, especially those located at step edges and surface defects; (b) difficulty in distinguishing the dynamic behavior of Brønsted and Lewis acid sites during chemisorption and physisorption; and (c) the lack of real-time spatially resolved acidity understanding across heterogeneous catalyst surfaces. Here, high-spatial-resolution mapping of acid sites in nanoparticles using synchrotron-based infrared microspectroscopy was elucidated by using pyridine as a probe molecule. This approach enables direct 2D spatial mapping and temperature-resolved analysis of Brønsted and Lewis acid sites in amorphous nanoparticles and micrograins, providing insights into the distribution and nature of acidity at the micro- to nanoscale.

Although traditional graphene-based absorbing materials exhibit excellent dielectric loss properties, they are prone to agglomeration and possess excessively high electrical conductivity, which can cause impedance mismatch and consequently degrade absorption performance. These limitations significantly constrain their application in electromagnetic wave absorption. Therefore, integrating graphene with other materials to reduce agglomeration, lower electrical conductivity, and enhance absorption performance is of great importance. This study proposes a low-solvent nanofluid composite strategy, where graphene oxide-coated silicon carbide (GO/SiC) serves as the core structure, with 3-Glycidoxypropyltrimethoxysilane (KH560) and Jeffamine M2070 (M2070) functioning as the corona and halo layers, respectively. Compared with graphene, GO induces additional surface defects, thereby enhancing dipole polarization; while SiC mitigates the excessive electrical conductivity of graphene, optimizes impedance matching, and creates heterogeneous interfaces to promote multiple internal reflections and interfacial effects. Moreover, the synergistic effect between KH560 and M2070 effectively suppresses GO agglomeration, enhances material fluidity, and facilitates interface heterogeneity. Compared with previously reported SiC-based composites (e.g., MWCNT/SiC with RL_min = −38.7 dB and EAB = 4.6 GHz), the GO/SiC-M2070 series composites in this study exhibit superior microwave absorption performance, with a minimum reflection loss (RL_min) as low as −47.0 dB and a maximum effective absorption bandwidth (EAB) of 7.94 GHz. This provides insights for the design of next-generation broadband and high-performance microwave absorbing materials.

The CO₂ adsorption and energy storage characteristics of Mn-based single atoms (SAs) and nanocrystals (NCs) (Mn sites stabilized by Mn–O bonds) arrayed in carbon aerogels (CAs), synthesized through a facile/one-pot synthesis route, are evaluated in detail. This involves studying the physiochemical properties of doped CAs with different manganese(II) acetate tetrahydrate ((CH₃COO)₂Mn·4H₂O) loadings and correlating it with CO₂ adsorption and energy storage efficiency. Pyrolysis of gel under an inert atmosphere leads to decomposition of (CH₃COO)₂Mn·4H₂O-induced activation of CAs. This dual role of (CH₃COO)₂Mn·4H₂O as a pore-activating agent and catalyst has a significant impact on morphology and porosity. The single ions/nanocrystals of Mn generated thereof act as efficient catalysts, aiding the CO₂ adsorption and energy storage. The developed material shows strong potential for direct air capture (DAC), exhibiting remarkable CO₂ capture ability (2.54 mmol·g^–1 at 15 mbar) along with high specific capacitance (C_sp) (136.4 F·g^–1 at 0.5 A·g^–1 using 1 M KOH solution) and excellent stability of 92% after 3000 cycles at 1 A·g^–1.