ACS Nano最新文献

Ubiquitous moisture is a colossal reservoir of clean energy, and the emergence of moisture-electric generators (MEGs) is expected to provide direct power support for off-grid electronic devices anytime and anywhere. However, most MEGs rely on auxiliary energy storage devices and rectifier circuits to drive small electronic devices, which hinder scalability and widespread deployment, and the development of direct current (DC) MEGs with high power output that can directly drive off-grid electronic devices is highly promising but challenging. Herein, a self-sustained moisture-electric generator (SMEG) with a hierarchical nanostructure based on one-dimensional (1D) negatively charged nanofibers and two-dimensional (2D) conductive nanosheets was demonstrated to generate continuous DC electricity from atmospheric humidity. Sulfation of bacterial cellulose nanofibers lowers the surface potential and increases the surface charge energy, and reduced graphene oxide (rGO) provides a conduction pathway for electrons. The hierarchical nanostructures constructed by the combination of 1D nanofibers and 2D nanosheets endow the SMEG with self-sustained moisture gradients and structural anisotropy, which force the generation of a pseudocurrent. This combination also constructs microcapacitors that further enhance the moisture-electric power output. The SMEG can generate a continuous voltage in excess of 0.54 V for over 2160 h, with a power density of about 822 μW cm^-3, demonstrating excellent operational durability. This research provides a feasible solution for the development of sustainable, versatile, and efficient power supplies for off-grid self-powered devices.

The integration of functional materials into electronic devices has become a key approach to extending Moore's law by increasing the functional density of electronic circuits. Here, we present a device technology based on ultrascaled ferroelectric, antiambipolar transistors (ferro-AAT) with robust negative transconductance, enabling a wide range of reconfigurable functionalities with applications in both the digital and analog domains. The device relies on the integration of a hafnia-based ferroelectric gate stack on a vertical nanowire tunnel field-effect transistor. Through intentional gate/source overlap and tunnel-junction engineering, we demonstrate enhanced antiambipolarity with a high negative transconductance that is reconfigurable using the nonvolatile remanent polarization of the ferroelectric. Experimental validation highlights the versatility of this ferro-AAT in two implementation scenarios: content addressable memory (CAM) for high-density data search and reconfigurable signal processing in analog circuits. As a single-transistor cell for CAMs, the ferro-AAT shows subpicojoule operation for one search with a compact footprint of ∼0.01 μm². For single-transistor-based signal modulation, multistate reconfigurations and high power conversion (>95%) are achieved in the ferro-AAT, resulting in a significant reduction in the complexity of analog circuit design. Our results reveal that the distinctive device properties allow ferro-AATs to operate beyond conventional transistors with multiple reconfigurable functionalities, ultrascaled footprint, and low power consumption.

Modular protein engineering is a powerful approach for fabricating high-molecular-weight assemblies and biomaterials with nanoscale precision. Herein, we address the challenge of designing an extended nanoscale filamentous architecture inspired by the central rod domain of human dystrophin, which protects sarcolemma during muscle contraction and consists of spectrin repeats composed of three-helical bundles. A module of three tandem spectrin repeats was used as a rigid building block self-assembling via coiled-coil (CC) dimer-forming peptides. CC peptides were precisely integrated to maintain the spectrin α-helix continuity in an appropriate frame to form extended nanorods. An orthogonal set of customizable CC heterodimers was harnessed for modular rigid domain association, which could be additionally regulated by metal ions and chelators. We achieved a robust assembly of rigid rods several micrometers in length, determined by atomic force microscopy and negative stain transmission electron microscopy. Furthermore, these rigid rods can serve as a scaffold for the decoration of diverse proteins or biologically active peptides along their length with adjustable spacing up to tens of nanometers, as confirmed by the DNA-PAINT super-resolution microscopy. This demonstrates the potential of modular bottom-up protein engineering and tunable CCs for the fabrication of functionalized protein biomaterials.

Mechanical forces shape living matter from the macro- to the microscale as both eukaryotic and prokaryotic cells are force wielders and sensors. However, whereas such forces have been used to control mechanically dependent behaviors in mammalian cells, we lack the same level of understanding in bacteria. Surface adhesion, the initial stages of biofilm formation and surface biofouling, is a mechanically dependent process, which makes it an ideal target for mechano-control. In this study, we employed nanometer surface vibrations to mechanically stimulate bacteria and investigate their effect on adhesion. We discovered that vibrational stimulation at the nanoscale consistently reduces surface adhesion by altering cell membrane potential. Our findings identify a link between bacteria electrophysiology and surface adhesion and provide evidence that the nanometric mechanical "tickling" of bacteria can inhibit surface adhesion.

Ultrawide bandgap semiconductors such as AlGaN, AlN, diamond, and β-Ga₂O₃ have significantly enhanced the functionality of electronic and optoelectronic devices, particularly in harsh environment conditions. However, some of these materials face challenges such as low thermal conductivity, limited P-type conductivity, and scalability issues, which can hinder device performance under extreme conditions like high temperature and irradiation. In this review paper, we explore the integration of various two-dimensional materials (2DMs) to address these challenges. These materials offer excellent properties such as high thermal conductivity, mechanical strength, and electrical properties. Notably, graphene, hexagonal boron nitride, transition metal dichalcogenides, 2D and quasi-2D Ga₂O₃, TeO₂, and others are investigated for their potential in improving ultrawide bandgap semiconductor-based devices. We highlight the significant improvement observed in the device performance after the incorporation of 2D materials. By leveraging the properties of these materials, ultrawide bandgap semiconductor devices demonstrate enhanced functionality and resilience in harsh environmental conditions. This review provides valuable insights into the role of 2D materials in advancing the field of ultrawide bandgap semiconductors and highlights opportunities for further research and development in this area.

Multidrug resistance (MDR) has emerged as a major barrier to effective breast cancer treatment, contributing to high rates of chemotherapy failure and disease recurrence. There is thus a pressing need to overcome MDR and to facilitate the efficient and precise treatment of breast cancer in a targeted manner. In this study, endogenous functional lipid droplets (IR780@LDs-Fe₃O₄/OA) were developed and used to effectively overcome the limited diffusion distance of reactive oxygen species owing to their amenability to cascade-targeted delivery, thereby facilitating precise and effective sonodynamic therapy (SDT) for MDR breast cancer. Initially, IR780@LDs-Fe₃O₄/OA was efficiently enriched within tumor sites in a static magnetic field, achieving the visualization of tumor treatment. Subsequently, the cascade-targeted SDT combined with the Fenton effect induced lysosome membrane permeabilization and relieved lysosomal sequestration, thus elevating drug concentration at the target site. This treatment approach also suppressed ATP production, thereby inhibiting P-glycoprotein-mediated chemotherapeutic drug efflux. This cascade-targeted SDT strategy significantly increased the sensitivity of MDR cells to doxorubicin, increasing the IC₅₀ value of doxorubicin by approximately 10-fold. Moreover, the cascade-targeted SDT also altered the gene expression profiles of MDR cells and suppressed the expression of MDR-related genes. In light of these promising results, the combination of cascade-targeted SDT and conventional chemotherapy holds great clinical promise as an effective treatment modality with excellent biocompatibility that can improve MDR breast cancer patient outcomes.