Abstract Carbon-based supercapacitors often suffer from limited capacitance, typically below 120 F g–1, even with structural modifications. This study achieves a significant capacitance boost, exceeding 200 F g–1, by ingeniously mitigating carrier asymmetry within both electrodes and electrolytes. Nitrogen- and boron-doped carbon, used as positive and negative electrodes, enhance the density of states and charge carrier mobility while compensating for quantum capacitance asymmetry. Concurrently, introducing isopropylammonium cations into the mixed electrolyte compresses the electric double layer, equalizing anionic and cationic charge disparities at the solid–liquid interface. This > 200 F g–1 value represents the highest gravimetric capacitance reported for carbon-based supercapacitors using organic electrolytes. Impressively, at a high current density of 100 A g–1, the device maintains 128 F g–1, outperforming commercial YP-50F at 1 A g–1. These results offer pivotal insights into overcoming supercapacitor capacitance limitations and understanding the fundamental enhancement mechanisms.
Abstract The coexistence of chirality and magnetism in nanomaterials has been observed with metallic complexes but remains rarely achieved in magnetic oxides. Here, we identify biologically induced chiroptical activity in the magnetotactic bacterium Magnetospirillum gryphiswaldense strain MSR-1, which biomineralizes Fe3O4 crystals within a prokaryotic organelle known as a magnetosome. Natural and magnetic circular dichroism spectra were recorded for wild-type MSR-1, a magnetosome-deficient mutant (ΔmamAB), and the magnetosomes extracted from the bacterial cells. While chiroptical signals appeared when the particles remained within the bacterial matrix, the isolated nanoparticles did not demonstrate detectable natural optical activity. Subsequent surface modification of the extracted optically inactive nanoparticles with enantiopure aspartic acid produced chiroptical responses. These observations suggest that the biological environment of magnetosomes imposes chiral asymmetry on magnetic nanoparticles and that surface functionalization revealed optical activity. The results collectively describe a biologically mediated induction of chiroptical signals in Fe3O4 nanoparticles.
Abstract Biomolecular corona (BC) governs nanoparticle (NP) interactions with biological systems. While the role of proteins in BC regulation is well recognized, the contribution of serum lipids remains largely unexplored. Here, silica magnetic NPs were incubated with normal or hyperlipidemic serum to form BC@NPs, followed by lipidomic and proteomic characterization using LC-MS/MS. Their cellular uptake, biodistribution, and hepatic clearance were subsequently evaluated. Hyperlipidemia profoundly remodeled BC composition, leading to reduced overall protein adsorption while enrichment of cholesterol, triglycerides, and apolipoproteins, particularly APOB, indicative competitive lipid-protein adsorption at the NP surface. This disease-associated BC remodeling enhanced macrophage uptake through LDL receptor–mediated endocytosis and lipid raft-dependent pathways, thereby leading to increased hepatic accumulation via facilitating the uptake by Kupffer cells and hepatocytes. By elucidating the interplay between lipids and proteins in BC formation, this work reveals a previously underappreciated role of serum lipids in regulating NP-bio interactions, especially in lipid-associated diseases.
Abstract Topological semimetals hold great promise for nonlinear optics (NLO). It is challenging to probe tilted Dirac fermion-driven intrinsic second harmonic generation (SHG) and topological band structure modulation of second-order nonlinearity in spatial inversion and time-reversal-symmetric nonmagnetic Dirac semimetals. Here, we identify NiTe2, featuring a type-II Dirac cone, as an ideal platform for investigating SHG in centrosymmetric crystals. Through comprehensive NLO measurements, we demonstrate that the highly efficient SHG emission in NiTe2 arises predominantly from bulk electric-quadrupole contribution. Under interband optical transition conditions, we quantify a giant effective nonlinear susceptibility |χEQ(3)q| ≈ 7.07 pm/V at 475 nm, which is an order of magnitude higher than that of commonly used NLO crystals. Furthermore, the striking spectral consistency between SHG and four-wave mixing (FWM) unambiguously identifies the shared interband excitation and radiation channels as the unified driving mechanism. Collectively, these findings pave the way for harnessing centrosymmetric topological semimetals in next-generation nonlinear optoelectronic devices.
Abstract Accurate detection of low-frequency single-nucleotide variants (SNVs) in a high wild-type (WT) background remains challenging. Here, we report a mismatch-engineered CRISPR transistor (MECT) for rapid, amplification-free detection of mutant RNA. MECT integrates a Cas13a–crRNA recognition interface with a graphene field-effect transistor and employs a spaced mismatch crRNA design centered on the mutation site in a nonseed region. It leverages the synergistic effect between natural and engineered mismatches at the mutation site to weaken WT binding while preserving mutant recognition, thereby amplifying the difference in response between mutants and the WT. Using BRAF V600E RNA as a target, MECT generates a mutant response approximately 11.58 times stronger than the WT background, with a detection limit of 3 × 10–18 mol L–1. MECT can also detect mutants as low as 0.0001% against a WT background. A portable MECT-based prototype is validated using cell-derived RNA and clinical samples, supporting decentralized analysis of low-frequency cancer mutations.
Abstract The high-voltage stability of P2-type layered oxide cathodes for sodium-ion batteries is closely related to their intrinsic structural characteristics. However, complex phase transitions and structural degradation at high voltage lead to rapid capacity decay. Here, a synergistic Li/Nb co-doped P2-type layered cathode is developed. Li doping disrupts Na+/vacancy ordering and redirects the high-voltage phase-transition pathway from a deleterious P2→O2 transition toward a milder Z-like O/P intergrowth evolution. Nb incorporation preserves this pathway while further reinforcing the transition-metal coordination environment. This dual modification suppresses local structural distortion, alleviates lattice strain, and mitigates irreversible oxygen release. Consequently, Na0.67Ni0.21Li0.11Mn0.63Nb0.05O2 exhibits 93.1% capacity retention after 100 cycles at 2C within 2.0–4.3 V. This work elucidates how elemental co-doping regulates local coordination and structural evolution during charge and discharge, offering a strategy for stabilizing P2-type layered oxide cathodes under high-voltage operation.
Abstract Silicon oxide (SiOx) is a promising anode for lithium-ion batteries, yet its practical application is hindered by multistep synthesis, hazardous silane-based routes, poor scalability, and sluggish electrochemical conversion. Herein, we report a low-cost and scalable strategy for constructing graphitic carbon-confined SiOx (SiOx@GC) anodes via all-process catalysis using waste-derived superabsorbent polymers and industrial by-product SiCl4 as carbon and silicon precursors, respectively. Ni species participate throughout by catalyzing carbon graphitization, mediating confined SiOx formation, and dynamically facilitating electrochemical conversion during cycling. This integrated Ni-enabled process promotes efficient SiOx formation and its deeper, more reversible conversion into electrochemically active silicon. Consequently, the SiOx@GC anode delivers 1147 mAh g–1 after 100 cycles at 0.1 A g–1, stable cycling over 1000 cycles at 5 A g–1, and a full-cell energy density of 353 Wh kg–1 after 250 cycles. This work establishes an all-process catalytic framework for coupling scalable SiOx synthesis with reversible electrochemical conversion.
Because of their high spatial resolution and wide range of signals that can be collected, electron microscopes offer a plethora of possibilities to characterize materials at the nanoscale. This mini-review focuses on a small subset of those, providing an overview of holographic techniques in transmission electron microscopy (TEM), such as off-axis holography, inline holography, differential phase contrast, tilt-corrected bright-field scanning TEM, and ptychography, for mapping electrostatic potentials in thin TEM specimens. We compare their intrinsic strengths and limitations and discuss some of their applications to nanoscale materials relevant to electronics, quantum technology, or energy conversion.
Interfacial hydration governs the biological response of polymeric biomaterials, yet directly visualizing solvation structures on soft, fluctuating polymer surfaces has remained experimentally challenging. Here we employ ultralow-noise frequency modulation atomic force microscopy (FM-AFM) to resolve the nanoscale hydration structures of blood-compatible poly(2-methoxyethyl acrylate) (PMEA) and protein-adsorbing poly(n-butyl methacrylate) (PBMA) in phosphate-buffered saline. Subnanometer frequency shift mapping combined with nanomechanical analysis reveals two distinct water architectures. PBMA shows a static multilayered structure with 0.30 nm periodicity, typical of hydrophobic surfaces such as graphite. In contrast, PMEA is exceptionally soft (apparent modulus E* ≈ 100 MPa) and, despite being fully hydrated, shows no detectable layering. We assign this absence of layering to a dynamically fluctuating, water-penetrated side-chain ("intermediate water") region, which has been proposed to act as a physical barrier against irreversible protein adsorption. Direct FM-AFM access to hydration structures at polymer-water interfaces should guide the design of blood-compatible biomaterials.
Abstract Artificial interfaces for lithium-metal anodes typically regulate nucleation after Li+ desolvation, while the preceding solvation-to-interface transition remains poorly controlled. Herein, we show that a yolk–shell H-Fe3O4@ZIF-67 interphase can act as a confined predesolvation layer. The subnanometer apertures of ZIF-67 sterically constrain intact solvated Li+ complexes, forcing partial solvent removal before electron transfer takes place. Polar Fe–O/Co–N environments favor anion-derived solid electrolyte interphase (SEI) chemistry, while the internal void accommodates the deposited Li. These coupled effects lower the Li nucleation overpotential to 14.6 mV, decrease the apparent interfacial activation energy to 34.53 kJ mol–1, and increase the Li+ transference number to 0.60. Symmetric cells operate for over 2000 h. High-loading LiFePO4 full cells retain 132.6 mAh g–1 after 400 cycles at 1 C and deliver an average Coulombic efficiency of 99.88%. Confining predesolvation at the molecular scale thus provides an effective strategy for stabilizing reactive metal anodes.
Abstract Friction is a key determinant governing energy dissipation at solid–water interfaces, but the interfacial friction mechanism remains poorly understood. Herein, we systematically investigated water slip in MoS2/(WS2, hBN, and graphene) van der Waals heterostructures (vdWHs) with MoS2 as the top layer. The water slip length increases from 9.6 nm on MoS2/WS2 to 12.8 nm on MoS2/hBN and reaches 36.7 nm on MoS2/graphene based on atomic force microscopy. Photoluminescence and Raman spectroscopy reveal charge transfer from vdWHs to water that strongly correlates with the water slip length. Simulations indicate that electron transfer from MoS2/WS2 to water enhances charge density at vdWHs–water interfaces, hindering water slip. In contrast, slight hole injection from MoS2/(hBN and graphene) into water reduces the residual interfacial charge, promoting water slip. Our findings elucidate friction mechanisms from the perspective of interfacial electronic friction, providing novel insights into energy transfer at vdWHs–water interfaces and a foundation for the design of advanced nanofluidic devices.
Abstract Flexible pressure sensors have been widely adopted in fields including e-skin and wearable devices. Compared with single-mode pressure sensing, pressure-position sensing can further provide positional information, endowing the system with multidimensional sensing capabilities. This is usually achieved using multiple sensing units. However, numerous sensing units often cause excessive wiring, large data volumes, and high energy consumption. Here, inspired by the slit unit collaborative mechanism of scorpions, designed a flexible pressure-position sensor (FPPS). It consists of a pressure-sensing layer, which is a single conductive layer, and a pressure-positioning layer, which contains three conductive layers. With only four signal channels, the FPPS can identify nine positional regions, thereby significantly reducing data complexity. Based on outstanding perception capabilities, such as low zero-drift (0.2%), fast response time (124 ms), and excellent stability (>14000), the FPPS is employed in digital input and control applications, demonstrating its potential in large-scale detection fields such as intelligent human–computer interaction.
Abstract Lipid droplets (LDs) are dynamic intracellular organelles that undergo extensive remodeling during adipocyte differentiation, yet how their mechanical properties evolve during late-stage maturation remains unexplored. Here, we apply Brillouin microscopy to map the viscoelastic properties of LDs in differentiating white (WAT) and brown (BAT) adipocytes over 34 days. LDs exhibit lineage-associated mechanical maturation characterized by distinct terminal states, elastic–dissipative relationships, and geometry–mechanics coupling. WAT droplets reach a higher mechanical end point, whereas BAT droplets remain in a lower viscoelastic regime and exhibit distinct temporal evolution of dissipative behavior. Notably, WAT transitions to a size-independent mechanical state, indicating decoupling of stiffness from geometric growth and a shift toward internal organization-dominated mechanics, while BAT maintains geometry–mechanics coupling. Across both lineages, Brillouin shift and line width remain strongly correlated. These findings establish LDs as dynamically evolving mechanical entities and uncover organelle-scale mechanics as a previously unrecognized dimension of adipocyte late-stage differentiation.
Abstract Noise measurements provide a valuable tool for revealing spin polarization effects in the electronic transport through quantum coherent conductors. We present an extension of the Landauer description of shot noise to include energy dependent transmission functions and apply it to explore local magnetic correlations in air oxidized copper contacts, for which first-principle studies have predicted the emergence of ferromagnetic ground states, attributing certain atomic configurations with spin filtering capabilities. By means of low-temperature transport measurements, we provide comprehensive experimental evidence, including hysteretic magnetoresistance and zero-bias anomalies (ZBAs) attributed to the Kondo effect, for the presence of local magnetism. The analysis of the anomalous shot noise in the presence of ZBAs allows us to determine the spin polarization of the current which may reach even full polarization, confirming the spin filtering capability of copper oxide atomic contacts.
Abstract In-plane anisotropic light propagation at the nanoscale enables directional, subwavelength control, yet its behavior in low-symmetry triclinic crystals remains underexplored because accessing the full dielectric tensor is challenging. Here, we use scattering-type scanning near-field optical microscopy to image mid-infrared waveguide modes in triclinic ReSe2 and directly reconstruct the in-plane dielectric tensor. We reveal principal axes rotated by ∼15° relative to the crystallographic axes and ultralow-loss guided modes propagating beyond 50 μm. Our approach is broadly applicable to other spectral ranges and low-symmetry van der Waals crystals. Integrating ReSe2 thin film with a SiC substrate, we engineer anisotropic, dielectric-tailored surface phonon polaritons exhibiting highly confined, directional fields. Nano-imaging provides a stringent validation of the reconstructed tensor. These findings establish a versatile platform for characterizing low-symmetry crystals and position ReSe2 as a promising component for anisotropic nanophotonic devices based on van der Waals materials.
Abstract We demonstrate negative differential conductance (NDC), consistent with extreme band filling, in titanium trisulfide (TiS3) nanowire field-effect transistors (FETs) subject to ionic gating. Electronic-structure calculations connect the NDC to the narrow and nonparabolic nature of the conduction band states in TiS3. These exhibit inflection points at relatively low energies, which become accessible when ionic gating induces extreme carrier concentration (∼1020 cm–3). In contrast with the Gunn effect, which requires electron–phonon scattering to transfer electrons between conduction-band valleys to initiate NDC, the mechanism here derives solely from single-carrier, intraband dynamics. As such, the potential should exist to exploit its associated NDC in ultrafast (i.e., terahertz) electronic devices. Since the NDC ultimately results from the heavily d-orbital character of the conduction-band states of TiS3, this phenomenon need not be unique to this material. This should motivate future studies of other materials with similarly strong nonparabolicity.
Abstract Metalenses offer a pathway toward flat, wafer-level optics, but their translation to mobile imaging has been hindered by the difficulty of achieving broadband performance at millimeter-scale apertures. Here we report a visible metalens that imparts a wavelength-invariant phase profile in a hybrid configuration with refractive elements. Central to this advance is a dispersion-contrasting metasurface that achieves broadband phase control using simple, photolithography-compatible nanostructures. Built from stacked silicon nitride nanohole and titanium dioxide nanopost arrays with opposite dispersion sensitivities, the device independently controls phase and group delay while maintaining high transmission across the visible. Integrated with refractive optics, it produces full-color photographic images free of visible artifacts under conditions representative of mobile camera modules. Interferometric measurements show that image quality is governed by phase fidelity of the metalens, demonstrating that accurate, manufacturable phase control provides a viable route toward integrating visible metalenses into compact imaging systems.
Abstract Photocatalytic therapy (PCT) has emerged as an expanded framework for light-driven biomedicine. Specifically, photodynamic therapy (PDT) can be regarded as a classical oxygen-sensitized subtype, while broader photocatalytic pathways, including photoredox transformations, intracellular polymerization, and photocatalytic gas generation, further extend its scope. However, organic photocatalytic systems often suffer from photobleaching, poor aqueous compatibility, and aggregation-caused quenching, which reduce excited-state utilization and catalytic efficiency in biological media. Aggregation-induced emission luminogens (AIEgens) offer a promising strategy by suppressing nonradiative decay. Moreover, aggregation engineering can regulate photocatalytic processes by modulating charge transfer and excited-state dynamics. This Mini-Review summarizes recent advances in AIE-based organic photocatalytic systems for biomedical applications. In this context, AIEgens and aggregation effects are emphasized not only for overcoming the deactivation of conventional organic systems in the aggregated state but also for providing versatile molecular design principles for the development of efficient and biologically adaptable organic photocatalytic therapeutics.
Abstract Magnesium (Mg) alloys are attractive lightweight metals but suffer from unstable friction and poor wear resistance. Here we show that the high electrochemical activity of Mg, typically viewed as detrimental, can drive the regeneration of lubricious nanoscale tribofilms during sliding. In deionized water, corrosion continuously supplies interfacial reaction products that repair mechanically disrupted films, converting severe tribo-oxidation in air into a corrosion-modulated self-regeneration process. While dry sliding typically leads to a highly unstable interface, the continuous formation of this regenerative layer in water imparts robust interfacial stability. This pathway reduces wear by more than 60% across the tested Mg-based materials. SiC-reinforced AZ91 Mg composites further stabilize the interface through load sharing, improved water spreading, and regulated aqueous corrosion. The optimized composite forms a uniform amorphous nanoscale tribofilm supported by a nanocrystalline gradient layer, giving a 77.2% wear reduction and outperforming 7050 Al under identical conditions. In contrast, Al-, Ti-, and Fe-based materials do not show comparable regeneration because their surfaces are relatively inert in water. These findings establish controlled corrosion as an active nanoscale design variable for self-adaptive tribological interfaces in Mg alloys.
Abstract Antibiotic-resistant infections remain a major barrier to wound care, motivating antimicrobial biomaterials that are effective and locally activatable. Here, we report infection-responsive iron-doped carbon dots (FeCDs) synthesized via a one-pot hydrothermal route using biocompatible iron(II) gluconate. FeCDs eradicate bacteria through synergistic dual pathways: (i) a contact-independent mechanism in which iron doping confers peroxidase-like activity to catalyze reactive oxygen species (ROS) generation in H2O2-rich infection microenvironments, amplifying localized oxidative stress; and (ii) a contact-dependent mechanism where FeCDs electrostatically bind to bacteria and drive material-bacteria interfacial electron transfer, disrupting respiratory chains and energy production. Combined experiments and molecular dynamics simulations substantiate this synergistic coupling between catalytic and bioelectronic kinetics. Consequently, FeCDs exhibit broad-spectrum antibacterial ability with a high bactericidal rate (98.91%), and significantly accelerate infected wound healing with excellent biosafety. This work advances scalable carbon-based nanozymes, and highlights respiratory electron disruption as a powerful and complementary modality for anti-infective therapy.
