Facile Synthesis of Manganese Tellurite Nanoparticles for Magnetic Resonance Imaging-Guided Photothermal Therapy

In this study, manganese tellurite (MnTeO₃) nanoparticles are developed as theranostic agents for magnetic resonance imaging (MRI)-guided photothermal therapy of tumor. MnTeO₃ nanoparticles are synthesized via a simple one-step method. The as-synthesized MnTeO₃ nanoparticles with uniform size show good biocompatibility. In particular, MnTeO₃ nanoparticles exhibit a high photothermal conversion efficiency (η = 26.3%), which is higher than that of gold nanorods. Moreover, MnTeO₃ nanoparticles also have high MRI performance. The longitudinal relaxivity (r₁) value of MnTeO₃ nanoparticles is determined to be 8.08 ± 0.2 mm ⁻¹ s⁻¹, which is higher than that of clinically approved T₁-contrast agents Gd-DTPA (4.49 ± 0.1 mm ⁻¹ s⁻¹). The subsequent MnTeO₃ nanoparticles-mediated photothermal therapy displays a highly efficient ablation of tumor cells both in vitro and in vivo with negligible toxicity. It is demonstrated that MnTeO₃ nanoparticles can serve as promising theranostic agents with great potentials for MRI-guided photothermal therapy.     

A combination of dispersive liquid–liquid microextraction and surface plasmon resonance sensing of gold nanoparticles for the determination of ziram pesticide

We have developed a reliable, fast, and highly sensitive analytical method utilizing dispersive liquid–liquid microextraction and gold nanoparticles probes for ziram (zinc bis(dimethyldithiocarbamate)) determination. The method is based on the in situ formation of gold nanoparticles in carbon tetrachloride as an organic phase. It was found that the trace levels of ziram influenced the formation of gold nanoparticles, leading to absorbance change of a sedimented phase. The results of the colorimetric ziram determination were in the concentration range of 0.12–2.52 ng/mL with a limit of detection of 0.06 ng/mL. The formation of the stable and dispersed gold nanoparticles in the organic phase provides a good precision for dispersive liquid–liquid microextraction method, resulting in the relative standard deviation of 3.8 and 1.2% for 0.56 and 1.58 ng/mL of ziram, respectively. This method has been successfully used for the ziram determination in samples of well and river water, soil, potato, carrot, wheat, and paddy soil.     

Advantageous Interfacial Effects of AgPd/g-C3N4 for Photocatalytic Hydrogen Evolution: Electronic Structure and H2O Dissociation

Bimetallic AgPd nanoparticles have been synthesized before, but the interfacial electronic effects of AgPd on the photocatalytic performance have been investigated less. In this work, the results of hydrogen evolution suggest that the bimetallic AgPd/g-C₃N₄ sample has superior activity to Ag/g-C₃N₄ and Pd/g-C₃N₄ photocatalysts. The UV/Vis diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, CO adsorption diffuse reflectance FTIR spectroscopy, and FTIR results demonstrate that in the AgPd/g-C₃N₄, the surface electronic structures of Pd and Ag are changed, which is beneficial for faster photogenerated electron transfer and greater H₂O molecule adsorption. In situ ESR spectra suggest that, under visible light irradiation, there is more H₂O dissociation to radical species on the AgPd/g-C₃N₄ photocatalyst. Furthermore, DFT calculations confirm the interfacial electronic effects of AgPd/g-C₃N₄, that is, Pd^δ−⋅⋅⋅Ag^δ+, and the activation energy of H₂O molecule dissociation on AgPd/g-C₃N₄ is the lowest, which is the main contributor to the enhanced photocatalytic H₂ evolution.     

Tumor‐Targeting W18O49 Nanoparticles for Dual‐Modality Imaging and Guided Heat‐Shock‐Response‐Inhibited Photothermal Therapy in Gastric Cancer

Photothermal therapy (PTT) is an emerging noninvasive and precise localized therapeutic modality; however, it is deeply limited by its poor tumor accumulation, inadequate photothermal conversion efficiency, and the thermoresistance of cancer cells. Aimed at these shortcomings, tumor‐targeting nanoparticles (iRGD‐W₁₈O₄₉‐17AAG) comprising carboxyl‐group‐functionalized W₁₈O₄₉ nanoparticles, integrin‐targeting peptide iRGD, and HSP90‐inhibitor 17AAG are developed. The W₁₈O₄₉ nanoparticles act as excellent PTT carriers and computed tomography (CT) imaging contrast agents. The ring type polypeptide iRGD promotes the accumulation of nanoparticles in the tumour and further penetration into cancer cells. The introduction of 17AAG can inhibit the heat‐shock response and overcome the thermoresistance, thus increasing the curative effect of PTT and reducing the chance of tumor recurrence. The W₁₈O₄₉ nanoparticles can also be used to monitor and guide the phototherapeutic through CT and near‐infrared fluorescence imaging after modification with Cy5.5. In addition, superior biosafety is also indicated in both preliminary in vitro and in vivo assessments. The potential of iRGD‐W₁₈O₄₉‐17AAG in tumor targeting, dual modality imaging‐guided and remarkable enhanced PTT of gastric cancer with ignorable side effect both in vitro and in vivo, which may be further applied in clinic, is highlighted.     

Display of Potassium Channel–Blocking Tertiapin‐Q Peptides on Gold Nanoparticles Enhances Depolarization of Cellular Membrane Potential

The use of nanoparticle (NP) systems to control cellular physiology, including membrane potential, can facilitate furthered understanding of many disparate cellular processes ranging from cellular proliferation to tissue regeneration. A gold NP (AuNP) bioconjugate system based on the honeybee venom peptide, tertiapin‐Q (AuNP‐TPN‐Q), that depolarizes membrane potential by targeting inward rectifier potassium channels (Kir), is developed. The conjugate elicits, in a peptide concentration–dependent manner, a greater and more rapid depolarization response compared to the free peptide alone. The specificity of the interaction of the AuNP‐TPN‐Q conjugate with the Kir channel using immunocytochemistry and competition binding assays is confirmed. It is further shown that membrane depolarization is photothermally reversible via the laser‐induced plasmonic heating of the AuNP, providing a level of control over Kir channels not afforded by currently available drugs. The functional nanobioconjugate described herein provides a new research tool for understanding the intricacies of ion channel activity and the modulation of cellular membrane potential.     

Aurophilic Interactions in the Self‐Assembly of Gold Nanoclusters into Nanoribbons with Enhanced Luminescence

Aurophilic interactions (Au^I???Au^I) are crucial in directing the supramolecular self‐assembly of many gold(I) compounds; however, this intriguing chemistry has been rarely explored for the self‐assembly of nanoscale building blocks. Herein, we report on studies on aurophilic interactions in the structure‐directed self‐assembly of ultrasmall gold nanoparticles or nanoclusters (NCs, <2 nm) using [Au₂₅(SR)₁₈]^? (SR=thiolate ligand) as a model cluster. The self‐assembly of NCs is initiated by surface‐motif reconstruction of [Au₂₅(SR)₁₈]^? from short SR‐[Au^I‐SR]₂ units to long SR‐[Au^I‐SR]_x (x>2) staples accompanied by structure modification of the intrinsic Au₁₃ kernel. Such motif reconstruction increases the content of Au^I species in the protecting shell of Au NCs, providing the structural basis for directed aurophilic interactions, which promote the self‐assembly of Au NCs into well‐defined nanoribbons in solution. More interestingly, the compact structure and effective aurophilic interactions in the nanoribbons significantly enhance the luminescence intensity of Au NCs with an absolute quantum yield of 6.2 % at room temperature.     

Synthesis of silver nanoparticles with different shapes

Today the synthesis of silver nanoparticles is very common due to their numerous applications in various fields. Silver nanoparticles have unique properties such as: optical and catalytic properties, which, depend on the size and shape of the produced nanoparticles. So, today the production of silver nanoparticles with different shapes which have various uses in different fields such as medicine, are noted by many researchers. This article, is an attempt to present an overview of the shape-controlled synthesis of silver nanoparticles using various methods.     

Ultrathin,Porous and Oxygen Vacancies‐Enriched Ag/WO3−x Heterostructures for Electrocatalytic Hydrogen Evolution

Exploring advanced electrocatalysts for electrocatalytic hydrogen evolution is highly desired but remains a challenge due to the lack of an efficient preparation method and reasonable structural design. Herein, we deliberately designed novel Ag/WO_3?x heterostructures through a supercritical CO₂‐assisted exfoliation‐oxidation route and the subsequent loading of Ag nanoparticles. The ultrathin and oxygen vacancies‐enriched WO_3?x nanosheets are ideal substrates for loading Ag nanoparticles, which can largely increase the active site density and improve electron transport. Besides, the resultant WO_3?x nanosheets with porous structure can form during the electrochemical cycling process induced by an electric field. As a result, the exquisite Ag/WO_3?x heterostructures show an enhanced hydrogen evolution reaction (HER) activity with a low onset overpotential of ≈30 mV, a small Tafel slope of ≈40 mV dec^?1 at 10 mA cm^?2, and as well as long‐term durability. This work sheds light on material design and preparation, and even opens up an avenue for the development of high‐efficiency electrocatalysts.     

Tips and Tricks for the Surface Engineering of Well-Ordered Morphologically Driven Silver-Based Nanomaterials

Particularly-shaped silver nanostructures are successfully applied in many scientific fields, such as nanotechnology, catalysis, (nano)engineering, optoelectronics, and sensing. In recent years, the production of shape-controlled silver-based nanostructures and the knowledge around this topic has grown significantly. Hence, on the basis of the most recent results reported in the literature, a critical analysis around the driving forces behind the synthesis of such nanostructures are proposed herein, pointing out the important role of surface-regulating agents in driving crystalline growth by favoring (or opposing) development along specific directions. Additionally, growth mechanisms of the different morphologies considered here are discussed in depth, and critical points highlighted.     

Palladium nanoparticles‐decorated triethanolammonium chloride ionic liquid‐modified TiO2 nanoparticles (TiO2/IL‐Pd): A highly active and recoverable catalyst for Suzuki–Miyaura cross‐coupling reaction in aqueous medium

In this work, an easily obtained procedure was successfully implemented to prepare novel palladium nanoparticles decorated on triethanolammonium chloride ionic liquid‐functionalized TiO₂ nanoparticles [TiO₂/IL‐Pd]. Different methods were carried out for characterizations of the synthesized nanocatalyst (HR‐TEM, XPS, XRD, FE‐SEM, EDX, FT‐IR and ICP). TiO₂/IL‐Pd indicated good catalytic activity for the Suzuki–Miyaura cross‐coupling reaction of arylboronic acid with different aryl halides in aqueous media at ambient temperature. The recycled catalyst was investigated with ICP to amount of Pd leaching after 6 times that had diminished slightly, Thus, was confirmed that the nanocatalyst has a good sustainability for C–C Suzuki–Miyaura coupling reaction. The catalyst can be conveniently separated by filtration of the reaction mixture and reused for 6 times without significant loss of its activity. It supplies an environmentally benign alternative path to the existing protocols for the Suzuki–Miyaura reaction.