Construction of a BiVO4/VS-MoS2 S-scheme heterojunction for efficient photocatalytic nitrogen fixation.

Photocatalytic nitrogen (N2) reduction to ammonia (NH3), adopting H2O as the electron source, suffers from low efficiency owing to the sluggish kinetics of N2 reduction and the requirement of a substantial thermodynamic driving force. Herein, we present a straightforward approach for the construction of an S-scheme heterojunction of BiVO4/VS-MoS2 to successfully achieve photocatalytic N2 fixation, which is manufactured by coupling an N2-activation component (VS-MoS2 nanosheet) and water-oxidation module (BiVO4 nanocrystal) through electrostatic self-assembly. The VS-MoS2 nanosheet, enriched with sulfur vacancies, plays a pivotal role in facilitating N2 adsorption and activation. Additionally, the construction of the S-scheme heterojunction enhances the driving force for water oxidation and improves charge separation. Under simulated sunlight irradiation (100 mW cm-2), BiVO4/VS-MoS2 exhibits efficient photocatalytic N2 reduction activity with H2O as the proton source, yielding NH3 at a rate of 132.8 µmol g-1 h-1, nearly 7 times higher than that of pure VS-MoS2. This study serves as a noteworthy example of efficient N2 reduction to NH3 under mild conditions.

Research trends of radiation induced temporal lobe injury in patients with nasopharyngeal carcinoma from 2000 to 2022: a bibliometric analysis.

BACKGROUND: In patients with nasopharyngeal cancer (NPC), radiation-induced temporal lobe injury (TLI) is the most dreaded late-stage complication following radiation therapy (RT). We currently lack a definitive algorithmic administration for this entity. In the meantime, the pathogenesis of TLI and the mechanism-based interventions to prevent or treat this adverse effect remain unknown. To better answer the aforementioned questions, it is necessary to comprehend the intellectual foundations and prospective trends of this field through bibliometric analysis. METHODS: Articles were gathered from the Web of Science Core Collection (WoSCC) database between 2000 and 2022. CiteSpace was utilized to create a country/institutional co-authorship network, perform dual-map analysis, and find keywords with citation bursts. VOSviewer was used to build networks based on author co-authorship, journal citation, co-citation analysis of authors, references, and journals, and keyword co-occurrence. RESULTS: A total of 140 articles and reviews were included in the final analysis. The number of publications has steadily increased with some fluctuations over the years. The country and institution contributing most to this field are the China and Sun Yat-Sen University. Han Fei was the most prolific author, while Lee Awm was the most frequently cited. The analysis of co-occurrence revealed three clusters, including: "radiation-induced injury or necrosis in NPC," "clinical studies on chemotherapy/radiotherapy complications and survival in recurrent NPC," and "IMRT/chemotherapy outcomes and toxicities in head and neck cancer"). Most recent keyword bursts were "volume," "temporal lobe injury," "toxicities," "model," "survival," "intensity modulated radiotherapy," "induced brain injury," "head and neck cancer," and "temporal lobe." CONCLUSION: This study provides some insights of the major areas of interest in the field of radiation-induced TLI in patients with NPC by bibliometric analyses. This study assists scholars in locating collaborators and significant literature in this field, provides guidance for publishing journals, and identifies research hotspots. This analysis acknowledges significant contributions to the discipline and encourages the scientific community to conduct additional research.

Effect of side-chain length on solute encapsulation by amphiphilic heterografted brush copolymers.

Anisotropic nanomaterials are non-spherical structures that possess unique shape-dependent physicochemical properties and functionalities. Inspired by the abundance of filamentous entities in nature, cylindrical nanostructures have gained significant attention due to their unique performance. Herein, we discuss the effect of side-chain length on the encapsulation properties of amphiphilic heterografted bottlebrushes. We observed that by grafting a long hydrophilic block to the double-brush, we were able to restrict solute-induced conformational changes, thus producing drug-loaded anisotropic carriers. Unimolecular encapsulation in brushes was solute-dependent as shown here for probucol and rose bengal lactone. Stabilization with an amphiphilic diblock copolymer-consisting of the same type of blocks as those comprising the heterografted brush-served to explain the solute-dependent behavior observed for brushes, suggesting that solutes with a higher propensity to nucleation could be more effectively stabilized by the anisotropic carrier in a unimolecular worm-like construct.

Disulfide-Mediated Bioconjugation: Disulfide Formation and Restructuring on the Surface of Nanomanufactured (Microfluidics) Nanoparticles.

This study is about (1) nanomanufacturing (focusing on microfluidic-assisted nanoprecipitation), (2) advanced colloid characterization (focusing on field flow fractionation), and (3) the possible restructuring of surface disulfides. Disulfides are dynamic and exchangeable groups, and here we specifically focus, first, on their use to introduce biofunctional groups and, second, on their re-organization, which may lead to variable surface chemistries and uncontrolled cell interactions. The particles were obtained via microfluidic-assisted (flow-focused) nanoprecipitation of poly(ethylene glycol)-b-poly(ε-caprolactone) bearing or not a 2-pyridyl disulfide (PDS) terminal group, which quantitatively exchanges with thiols in solution. In this study, we have paid specific attention to size characterization, thereby also demonstrating the limitations of dynamic light scattering (DLS) as a stand-alone technique. By using asymmetric flow field flow fractionation coupled with DLS, static light scattering (SLS), and refractive index detectors, we show that relatively small amounts of >100 nm aggregates (cryogenic transmission electron microscopy and SLS/DLS comparison suggesting them to be wormlike micelles) dominated the stand-alone DLS results, whereas the "real" size distributions picked <50 nm. Our key result is that the kinetics of the conjugation based on PDS-thiol exchange was controlled by the thiol pKa, and this also determined the rate of the exchange between the resulting disulfides and glutathione (GSH). In particular, more acidic thiols (e.g., peptides, where a cysteine is flanked by cationic residues) react faster with PDS, but their disulfides hardly exchange with GSH; the reverse applies to thiols with a higher pKa. Disulfides that resist against restructuring via thiol-disulfide exchange allow for a stable bioconjugation, although they may be bad news for payload release under reducing conditions. However, experiments of both thiol release and nanoparticles uptake in cells (HCT116) show that also the disulfides formed from less-acidic and, therefore, less-reactive, and more exchangeable thiols were stable for at least a few hours even in a GSH-rich (10 mM) environment; this suggests a sufficiently long stability of surface groups to achieve, for example, a cell-targeting effect.

Intermittent High Glucose Exacerbates A-FABP Activation and Inflammatory Response through TLR4-JNK Signaling in THP-1 Cells.

BACKGROUND: Glucose fluctuation confers additional risks on diabetes-related vascular diseases, but the underlying mechanisms are unknown. Macrophage activation mediated by TLR4-JNK signaling plays an important role during the progress of diabetes. In the present study, we hypothesize that glucose fluctuation results in macrophage inflammation through TLR4-JNK signaling pathways. METHODS: THP-1 cells were treated with normal glucose (5 mM), constant high glucose (25 mM), and intermittent high glucose (rotation per 6 h in 5 mM or 25 mM) for 24 h. The mRNA and protein expression levels of TLR4, p-JNK, and adipocyte fatty acid-binding protein (A-FABP) were determined, and the proinflammatory cytokines TNF-α and IL-1ß were quantified. RESULTS: In constant high glucose, TLR4 expression and JNK phosphorylation levels increased, and this effect was more pronounced in intermittent high glucose. Accordingly, the expression of A-FABP and the release of the proinflammatory cytokines TNF-α and IL-1ß also increased in response to constant high glucose, an effect that also was more evident in intermittent high glucose. The inhibition of p-JNK by SP600125 did not attenuate TLR4 expression, but totally inhibited both A-FABP expression and the production of the proinflammatory cytokines TNF-α and IL-1ß in both constant and intermittent high glucose. CONCLUSIONS: Intermittent high glucose potentiates A-FABP activation and inflammatory responses via TLR4/p-JNK signaling in THP-1 cells. These findings suggest a more detrimental impact of glucose fluctuation on macrophage inflammation in diabetes-related vascular diseases than thus far generally assumed.

Core-shell Structure and Aggregation Number of Micelles Composed of Amphiphilic Block Copolymers and Amphiphilic Heterografted Polymer Brushes Determined by Small-Angle X-ray Scattering.

A large group of functional nanomaterials employed in biomedical applications, including targeted drug delivery, relies on amphiphilic polymers to encapsulate therapeutic payloads via self-assembly processes. Knowledge of the micelle structures will provide critical insights into design of polymeric drug delivery systems. Core-shell micelles composed of linear diblock copolymers poly(ethylene glycol)-b-poly(caprolactone) (PEG-b-PCL), poly(ethylene oxide)-b-poly(lactic acid) (PEG-b-PLA), as well as a heterografted brush consisting of a poly(glycidyl methacrylate) backbone with PEG and PLA branches (PGMA-g-PEG/PLA) were characterized by dynamic light scattering (DLS) and small angle X-ray scattering (SAXS) measurements to gain structural information regarding the particle morphology, core-shell size, and aggregation number. The structural information at this quasi-equilibrium state can also be used as a reference when studying the kinetics of polymer micellization.

Macromolecular Brushes as Stabilizers of Hydrophobic Solute Nanoparticles.

Macromolecular brushes bearing poly(ethylene glycol) and poly(d,l-lactide) side chains were used to stabilize hydrophobic solute nanoparticles formed by a rapid change in solvent quality. Unlike linear diblock copolymers with the same hydrophilic and hydrophobic block chemistries, the brush copolymer enabled the formation of ellipsoidal ß-carotene nanoparticles, which in cosolvent mixtures developed into rod-like structures, resulting from a combination of Ostwald ripening and particle aggregation. The stabilizing ability of the copolymer was highly dependent on the mobility of the hydrophobic component, influenced by its molecular weight. As shown here, asymmetric amphiphilic macromolecular brushes of this type may be used as hydrophobic drug stabilizers and potentially assist the shape control of nonspherical aggregate morphologies.

Nanoparticle stability in biologically relevant media: influence of polymer architecture.

We have contrasted the behavior of nanoparticles formed by the self-assembly of polymers based on poly(ethylene glycol) (PEG) and poly(D,L-lactide), with linear, linear-dendritic and bottle-brush architectures in biologically relevant media. Polymer PEG content ranged between 14% and 46% w/w, and self-assembly was triggered by a rapid and large change in solvent quality inside a four-stream vortex mixer. We examined nanoparticle interaction with human serum albumin (HSA), and solute release in the presence of fetal bovine serum. Dynamic light scattering data showed that PEG surface brushes of all nanoparticles provided effective steric stabilization, thus limiting their interaction with human serum albumin. Calorimetric experiments revealed that nanoparticle-HSA interaction was relatively weak and enthalpically driven, whereas dynamic light scattering results of incubated nanoparticles showed the absence of larger aggregates for most of the polymers examined. Solute core partitioning was examined by the loss of Forster resonance energy transfer (FRET) from a core-loaded donor-acceptor pair. The rate and magnitude of FRET efficiency loss was strongly dependent on the polymer architecture, and was found to be lowest for the bottle-brush, attributed to its covalent nature. Collectively, these findings are expected to impact the molecular design of increasingly stable polymeric carriers for drug delivery applications.

Toroidal structures from brush amphiphiles.

The self-assembly of macromolecular brushes of varying amphiphilic character from homogeneous solution under rapid assembly conditions results in unique morphologies, distinct from equilibrium structures. Kinetic features of the assembly process enabled the formation of toroid structures, the sizes of which were readily tuned according to solvent quality.