Ligand-regulated self-assembly of luminescent Au nanoparticles towards diverse controllable superstructures

Controlling NIR-II emitting gold organic/inorganic nanohybrids with tunable morphology and surface PEG density for dynamic visualization of vascular dysfunction

Luminescent Au nanoparticles (AuNPs) and their organic/inorganic nanohybrids are of interest due to their favorable properties and promising biomedical applications. However, most existing AuNP-based hybrid nanostructures cannot satisfy high efficiency in synthesis, deep tissue penetration, and long blood circulation simultaneously, thus cannot be employed in dynamic monitoring of biomedical applications. In this paper, using Pluronic F127 as a template, we report a robust approach for one-pot synthesis of AuNP-based organic/inorganic nanohybrids (AuNHs) with bright luminescence in the second near-infrared (NIR-II) window, tunable shape, and controllable surface polyethylene glycol (PEG) density. The nanohybrids could be controlled from a necklace-like shape with a dense brush PEG configuration to a spherical structure with a brush PEG coating, which greatly impacts the in vivo biological behavior. Compared to spherical AuNHs, the necklace-shaped AuNHs present a higher quantum yield and longer blood circulation, which are superior to most of the individual AuNPs. With these outstanding features, the necklace-shaped AuNHs could achieve real-time, dynamic visualization of vascular dysfunction, capable of directing the precise administration of thrombolytics (a medicine for the breakdown of blood clots). These findings could provide a powerful guide for designing novel NIR-II nanoprobes toward in vivo dynamic information visualization.

Anti-Coronaviral Nanocluster Restrain Infections of SARS-CoV-2 and Associated Mutants through Virucidal Inhibition and 3CL Protease Inactivation

Antivirals that can combat coronaviruses, including SARS-CoV-2 and associated mutants, are urgently needed but lacking. Simultaneously targeting the viral physical structure and replication cycle can endow antivirals with sustainable and broad-spectrum anti-coronavirus efficacy, which is difficult to achieve using a single small-molecule antiviral. Thus, a library of nanomaterials on GX_P2V, a SARS-CoV-2-like coronavirus of pangolin origin, is screened and a surface-functionalized gold nanocluster (TMA-GNC) is identified as the top hit. TMA-GNC inhibits transcription- and replication-competent SARS-CoV-2 virus-like particles and all tested pseudoviruses of SARS-CoV-2 variants. TMA-GNC prevents viral dissemination through destroying membrane integrity physically to enable a virucidal effect, interfering with viral replication by inactivating 3CL protease and priming the innate immune system against coronavirus infection. TMA-GNC exhibits biocompatibility and significantly reduces viral titers, inflammation, and pathological injury in lungs and tracheas of GX_P2V-infected hamsters. TMA-GNC may have a role in controlling the COVID-19 pandemic and inhibiting future emerging coronaviruses or variants.

Phase Behavior and Aggregate Transition Based on Co-assembly of Negatively Charged Carbon Dots and a pH-Responsive Tertiary Amine Cationic Surfactant

We studied the co-assembly of an oppositely changed binary mixture of selenium-doped carbon quantum dots (Se-CQDs) and N,N-dimethyl octylamide-propyl tertiary amine (DOAPA) through turbidity, ζ potential measurement, and cryogenic transmission electron microscopy (cryo-TEM) with the aim of fabricating supramolecular assemblies with multiple dimensions and novel morphologies. The Se-CQD/DOAPA binary mixture exhibited abundant phase behavior, in which an isotropic phase (I₁) was first observed, followed by turbidity (T), precipitation (P), and a second isotropic phase (I₂), as the DOAPA concentration increased. Then we focused on investigating the morphologies of samples. In cryo-TEM observations, spherical aggregates were observed in all phase sequences, whereas the aggregates have different ζ potentials and sizes. In the I₂ phase, interesting nanocapsule-like aggregates and spindle-like aggregates can be identified in addition to spherical aggregates. In combination with the rheological behaviors of the I₂ phase solution and the detailed structure of the aggregates from enlarged cryo-TEM images, it is possible that the Se-CQDs and DOAPA co-assemble with novel network-like building blocks. The turbid solutions were found to be responsive to pH in phase P, and spherical aggregates were obtained at pH 6.5 but turned into vesicles when the pH reached 5.0. On the basis of these findings, CQDs and surfactants can be good structural building blocks for supramolecular structures, and the diverse morphologies of aggregates offer the prospect of multiple applications in the future.

Modulating luminescence and assembled shapes of ultrasmall Au nanoparticles towards hierarchical information encryption

Because of their intriguing luminescence performances, ultrasmall Au nanoparticles (AuNPs) and their assemblies hold great potential in diverse applications, including information security. However, modulating luminescence and assembled shapes of ultrasmall AuNPs to achieve a high-security level of stored information is an enduring and significant challenge. Herein, we report a facile strategy using Pluronic F127 as an adaptive template for preparing Au nanoassemblies (AuNAs) with controllable structures and tunable luminescence to realize hierarchical information encryption through modulating excitation light. The template guided ultrasmall AuNP in situ growth in the inner core and assembled these ultrasmall AuNPs into intriguing necklace-like or spherical nanoarchitectures. By regulating the type of ligand and reductant, their emission was also tunable, ranging from green to the second near-infrared (NIR-II) region. The excitation-dependent emission could be shifted from red to NIR-II, and this significant shift was considerably distinct from the small range variation of conventional nanomaterials in the visible region. In virtue of tunable luminescence and controllable structures, we expanded their potential utility to hierarchical information encryption, and the true information could be decrypted in a two-step sequential manner by regulating excitation light. These findings provided a novel pathway for creating uniform nanomaterials with desired functions for potential applications in information security.

Two dimensional BP@AuNP nanocomposites for photothermal/photodynamic therapy mediated wound disinfection and infected wound healing under a single light source

BP@AuNP nanocomposites can perform photothermal and photodynamic therapies simultaneously and exhibited a synergistic combination of multiple therapies for S. aureus and E. coli under a 650 nm laser.