ACS Nano最新文献

Quantitative analysis of protein interactions and the formation of higher-order assemblies in living cells remain major challenges. Here, we introduce a versatile nanopatterning toolbox that employs capillary nanostamping of functionalized polymers to generate high-contrast biofunctionalized nanodot arrays (bNDAs) with diameters below 500 nm. By leveraging orthogonal adaptor designs, we achieve robust immobilization of diverse fluorescent protein fusions, enabling simultaneous and selective spatially controlled enrichment of cytosolic proteins into high-density cytosolic nanodot arrays (cNDAs). Focusing on the assembly of the multimeric myddosome complex, we demonstrate density-dependent recruitment and colocalization of the core components MyD88, IRAK4, IRAK1, and TRAF6 within cNDAs. Super-resolution microscopy revealed the distinct nanoscale clustering of MyD88 and IRAK4 and uncovered the ultrastructural architecture of IRAK4 oligomers. These analyses highlight the spatial organization and hierarchical assembly of the myddosome at the nanoscale in the native cellular context. Collectively, our findings establish cNDAs as a powerful platform for reconstituting and analyzing intricate multiprotein assemblies in live cells, offering exciting opportunities for elucidating the mechanistic principles underlying complex protein networks.

Two-dimensional (2D) van der Waals heterostructures based on d-electron materials offer a platform for realizing heavy-Fermion systems with Kondo lattices. However, the nondestructive and reversible manipulation of spins at the nanoscale in 2D heavy-Fermion materials─essential for their application in spintronic devices─remains elusive. In this paper, we successfully manipulate and characterize both spin (Kondo effects) and electronic (charge density wave) degrees of freedom in the 2D heavy-Fermion system of 1T/1H-TaSe₂ heterostructure using scanning tunneling microscopy/spectroscopy (STM/STS). By applying voltage pulses, we precisely control the chirality and arrangement of the charge density wave coupled with local spins in 1T-TaSe₂. This process also leads to the generation and annihilation of two distinct types of domain walls (DWs). Combining STS and first-principles calculations, we reveal that the local spins are quenched in the type-II DW, which forms between two domains exhibiting a phase shift yet possessing identical chirality. This results in the disappearance of the Kondo resonance. The Mott phase also quenches within type-II DWs. Our results demonstrate a nondestructive and reversible approach to manipulate and understand the local spins of the Kondo lattice in artificial 2D heavy-Fermion systems with nanoscale precision.

Digital immunoassays enable highly sensitive detection of biomolecules, offering absolute quantification rather than relying on bulk signal intensity. We adapt a digital immunoassay scheme for a nanopore sensor, a versatile platform for single-molecule counting. Current nanopore sensors have demonstrated great progress when counting nucleic acids but struggle with proteins due to variability in translocation behavior and limited recognition strategies. While recent advancements have highlighted the promise of nanopore platforms for protein studies, precise quantification remains a challenge. Here, building on previous work, we present a nanopore-based digital immunoassay that employs gold nanoparticle-mediated molecular amplification with a single-molecule readout. This approach translates protein recognition into quantifiable DNA, enabling a precise digital assay. This assay employs a DNA NanoLock probe combined with a paramagnetic bead-based immunocapture, where the target proteins trigger a structural transformation of the NanoLock, converting their presence into a binary DNA-based signal. By incorporating AuNPs carrying hundreds of DNA proxy reporters, we effectively amplify the detectable signal by 2 orders of magnitude, significantly improving sensitivity. We validate the performance of this system by detecting the glial fibrillary acidic protein, a biomarker for traumatic brain injury and neurodegenerative diseases, in plasma samples and demonstrate high femtomolar-level sensitivity (∼40 pg/mL). Using the NanoLock probe, we further mitigate previous challenges, with reduced assay times (hours) and extended dynamic range (3-log). The self-calibrating nature of this digital approach offers robust, reproducible measurements across different nanopores, eliminating interdevice variability.

While traditional Pt-based catalysts suffer from inadequate selectivity and stability in electrocatalytic ethylene glycol oxidation reactions, we present a general and scalable synthesis strategy, fabricating a broad multimetallic Pt-based alloy nanowires (NWs) library from binary to quinary. Among these, the PtAgCuRhRu NWs exhibit exceptional performance, with a mass activity ∼8 times higher than that of Pt/C and a Faradaic efficiency for glycolic acid (GA) reaching 93.49%. In the membrane electrode assembly electrolyzer, the catalyst maintained its activity over 140 h with 99% GA selectivity. In situ experimental and theoretical calculations reveal oxygenophilic Rh and Ru promote *OH adsorption, facilitating the conversion of *COCH₂OH to GA and the oxidative removal of CO_ads, enhancing activity and stability. Additionally, the high energy barrier for C-C bond cleavage suppresses undesired decomposition due to the introduction of Ag and Cu, leading to superior GA selectivity.