Nanoscale Horizons最新文献

Expression of concern for ‘Carbon quantum dots as a dual platform for the inhibition and light-based destruction of collagen fibers: implications for the treatment of eye floaters’ by Alexandre Barras et al., Nanoscale Horiz., 2021, 6, 449–461, https://doi.org/10.1039/D1NH00157D.

The utilization of precise materials in heterogeneous catalysis will provide various new possibilities for developing superior catalysts to tackle worldwide energy and environmental issues. In recent years, single atom catalysts (SACs) with excellent atom utilization and isolated active sites have progressed dramatically as a thriving sector of catalysis research. Additionally, SACs bridge the gap between homogeneous and heterogeneous catalysts and overcome the limitations of both categories. Current research on SACs is highly oriented towards the organic synthesis of high-significance molecules with promising potential for large-scale applicability and industrialization. In this context, this review aims to comprehensively analyze the state-of-the-art research in the synthesis of SACs and analyze their structural, electronic, and geometric properties. Moreover, the unprecedented catalytic performance of the SACs towards various organic transformation reactions is succinctly summarized with recent reports. Further, a detailed summary of the current state of the research field of SACs in organic transformation is discussed. Finally, a critical analysis of the existing challenges in this emerging field of SACs and the possible countermeasures are provided. We believe that SACs have the potential to profoundly alter the chemical industry, pushing the boundaries of catalysis in new and undiscovered territory.

Recent developments in optical imaging techniques, particularly multi-photon excitation microscopy that allows studies of biological interactions at a deep cellular level, have motivated intensive research in developing multi-photon absorption fluorophores. Biological tissues are optically transparent in the near-infrared region. Therefore, fluorophores that can absorb light in the near-infrared (NIR) region by multi-photon absorption are particularly useful in bio-imaging. For instance, photoluminescence from ligand-protected gold nanoclusters has drawn extensive research interest in the past decade due to their bright, non-blinking, stable emission and tunability from the blue to the NIR emission. In this work, using the control of single metal doping on silver nanoclusters (Ag₂₅ protected by thiolate SR = 2,4-dimethylbenzenethiol (DMBT) ligand), we aim to explore the effects of metal doping on the (photo)stability and nonlinear optical response of liganded nanoclusters. We study two-photon excited photoluminescence and the second harmonic response upon excitation in the NIR (780–950 nm) range. Particular emphasis is placed on the effect of metal doping on the second-order nonlinear optical scattering properties (first hyperpolarizability, β(2ω)) of Ag₂₅ nanoclusters. In addition, β(2ω) values are one order higher than the one reported for Au₂₅ nanoclusters and represent the largest values ever reported for ligand-protected nanoclusters. Such enhanced hyperpolarizability leads to a strong second harmonic response and renders them attractive targets in bioimaging.

It is challenging to reconfigure devices at molecular length scales. Here we report molecular junctions based on molecular switches that toggle stably and reliably between multiple operations to reconfigure electronic devices at molecular length scales. Rather than static on/off switches that always revert to the same state, our voltage-driven molecular device dynamically switches between high and low conduction states during six consecutive proton-coupled electron transfer steps. By changing the applied voltage, different states are accessed resulting in in operando reconfigurable electronic functionalities of variable resistor, diode, memory, and NDR (negative differential conductance). The switching behavior is voltage driven but also has time-dependent features making it possible to access different memory states. This multi-functional switch represents molecular scale hardware operable in solid-state devices (in the form of electrode–monolayer–electrode junctions) that are interesting for areas of research where it is important to have access to time-dependent changes such as brain-inspired (or neuromorphic) electronics.

The supramolecular self-assembly of peptides offers a promising avenue for both materials science and biological applications. Peptides have garnered significant attention in molecular self-assembly, forming diverse nanostructures with α-helix, β-sheet, and random coil conformations. These self-assembly processes are primarily driven by the amphiphilic nature of peptides and stabilized by non-covalent interactions, leading to complex nanoarchitectures responsive to environmental stimuli. While extensively studied in biomedical applications, including drug delivery and tissue engineering, their potential applications in the fields of piezoresponsive materials, conducting materials, catalysis and energy harvesting remain underexplored. This review comprehensively elucidates the diverse material characteristics and applications of self-assembled peptides. We discuss the multi-stimuli-responsiveness of peptide self-assemblies and their roles as energy harvesters, catalysts, liquid crystalline materials, glass materials and contributors to electrical conductivity. Additionally, we address the challenges and present future perspectives associated with peptide nanomaterials. This review aims to provide insights into the versatile applications of peptide self-assemblies while concisely summarizing their well-established biomedical roles that have previously been extensively reviewed by various research groups, including our group.

Our Emerging Investigator Series features exceptional work by early-career nanoscience and nanotechnology researchers. Read Mohammad Malakooti’s Emerging Investigator Series article ‘Green synthesis of iron-doped graphene quantum dots: an efficient nanozyme for glucose sensing’ (https://doi.org/10.1039/D4NH00024B) and read more about him in the interview below.

The advent of the novel in-sensor/near-sensor computing paradigm significantly eliminates the need for frequent data transfer between sensory terminals and processing units by integrating sensing and computing functions into a single device. This approach surpasses the traditional configuration of separate sensing and processing units, thereby greatly simplifying system complexity. Two-dimensional materials (2DMs) show immense promise for implementing in-sensor computing systems owing to their exceptional material properties and the flexibility they offer in designing innovative device architectures with heterostructures. This review highlights recent progress and advancements in 2DM-based in-sensor computing research, summarizing the unique physical mechanisms that can be leveraged in 2DM-based devices to achieve sensory responses and the essential biomimetic synaptic characteristics for computing functions. Additionally, the potential applications of 2DM-based in-sensor computing systems are discussed and categorized. This review concludes with a perspective on future development directions for 2DM-based in-sensor computing.

Nanoparticle interactions with biological systems are intricate processes influenced by various factors, among which the formation of protein corona plays a pivotal role. This research investigates a novel aspect of nanoprotein corona–cell interactions, focusing on the impact of the protein corona on the recovery of disrupted tight junctions in endothelial cells. We demonstrate that the protein corona formed on the surface of star-shaped nanoparticles induces the aggregates of ZO-1, which is quite important for the barriers’ integrity. Our research emphasizes that the APOA1 pre-coating on the nanoparticles reduces the ZO-1 expression of endothelial cells offering a promising strategy for overcoming the bio barriers. These findings contribute to our understanding of the interplay between nanoparticles, protein corona, and endothelial cell junctions, offering insights for developing innovative therapeutic approaches targeting the blood–brain barrier integrity. Our study holds promise for the future of nanomedicine, nano drug delivery systems and development of strategies to mitigate potential adverse effects.

The importance of hardware security increases significantly to protect the vast amounts of private data stored on edge devices. Physical unclonable functions (PUFs) are gaining prominence as hardware security primitives due to their ability to generate true random digital keys by exploiting the inherent randomness of the physical devices. Traditional approaches, however, require significant data movement between memory units and PUF generation circuits to perform encryption, presenting considerable energy efficiency and security challenges. This study introduces an innovative approach where PUF key generation and encryption are accomplished in the same vertically integrated resistive random access memory (V-RRAM), alleviating the data movement issue. The proposed V-RRAM encryption machine offers concealable PUFs, high area efficiency, and multi-thread data handling using parallel XOR logic operations. The encryption machine is compared with other machines, demonstrating the highest spatiotemporal cost-effectiveness.

Initially observed on synthetic nanoparticles, the existence of biomolecular corona and its role in determining nanoparticle identity and function are now beginning to be acknowledged in biogenic nanoparticles, particularly in extracellular vesicles – membrane-enclosed nanoparticle shuttling proteins, nucleic acids, and metabolites which are released by cells for physiological and pathological communication – we developed a methodology based on fluorescence correlation spectroscopy to track biomolecular corona formation on extracellular vesicles derived from human red blood cells and amniotic membrane mesenchymal stromal cells when these vesicles are dispersed in human plasma. The methodology allows for tracking corona dynamics in situ under physiological conditions. Results evidence that the two extracellular vesicle populations feature distinct corona dynamics. These findings indicate that the dynamics of the biomolecular corona may ultimately be linked to the cellular origin of the extracellular vesicles, revealing an additional level of heterogeneity, and possibly of bionanoscale identity, that characterizes circulating extracellular vesicles.