Formation of Metal Selenide and Metal-Selenium Nanoparticles using Distinct Reactivity between Selenium and Noble Metals

Acoustic-Activated Se Crystalline Nanodomains at Atomically-Thin Liquid-Metal Piezoelectric Heterointerfaces for Synergistic CO2 Conversion

Acoustic-activated polarization at two-dimensional (2D) domains provide supplementary mechanisms for adjustment of empty and occupied orbitals at material heterointerfaces, activating a wide range of physicochemical applications. The piezoelectric nanodomains grown at 2D liquid-metal heterointerfaces represent a new class of polarization-dependent hybrid nanostructures with a highly challenging fabrication process. Here, the controlled growth of selenium-rich piezoelectric nanodomains on the nonpolar 2D surface of liquid Ga-based nanoparticles (NPs) enabled highly efficient and sustainable CO2 conversion. The Ga-based NPs were engulfed in carbon nanotube (CNT) frameworks. The initial hindrance effects of CNT frameworks suppressed the undesirable Ga-Se amalgamation to guarantee the suitable functions of piezocatalyst. Simultaneously, the CNT-Se mesoporous network enhances the transport and interaction of ionic species at heterointerfaces, providing unique selectivity features for CO2 conversion. Driven by acoustic energy, the multiple contributions of Ga-Se polarized heterointerfaces facilitated the piezoelectric switching and therefore increased the CO2 conversion efficiency to the value of 95.8%. The inherent compositional and functional tunability of the Ga-Se nanojunction reveal superior control over the catalyst heterointerfaces and thereby show promising potential for nanoscale applications.

Plasmonic Nanodomains Decorated on Two-Dimensional Oxide Semiconductors for Photonic-Assisted CO2 Conversion

Plasmonic nanostructures ensure the reception and harvesting of visible lights for novel photonic applications. In this area, plasmonic crystalline nanodomains decorated on the surface of two-dimensional (2D) semiconductor materials represent a new class of hybrid nanostructures. These plasmonic nanodomains activate supplementary mechanisms at material heterointerfaces, enabling the transfer of photogenerated charge carriers from plasmonic antennae into adjacent 2D semiconductors and therefore activate a wide range of visible-light assisted applications. Here, the controlled growth of crystalline plasmonic nanodomains on 2D Ga₂O₃ nanosheets was achieved by sonochemical-assisted synthesis. In this technique, Ag and Se nanodomains grew on 2D surface oxide films of gallium-based alloy. The multiple contribution of plasmonic nanodomains enabled the visible-light-assisted hot-electron generation at 2D plasmonic hybrid interfaces, and therefore considerably altered the photonic properties of the 2D Ga₂O₃ nanosheets. Specifically, the multiple contribution of semiconductor-plasmonic hybrid 2D heterointerfaces enabled efficient CO₂ conversion through combined photocatalysis and triboelectric-activated catalysis. The solar-powered acoustic-activated conversion approach of the present study enabled us to achieve the CO₂ conversion efficiency of more than 94% in the reaction chambers containing 2D Ga₂O₃-Ag nanosheets.

Diallyl disulphide-loaded spherical gold nanoparticles and acorn-like silver nanoparticles synthesised using onion extract: catalytic activity and cytotoxicity

Onion (Allium cepa) extract was used for the green synthesis of gold and silver nanoparticles. Each colloidal solution exhibited surface plasmon resonance, with a peak at 532 nm for gold nanoparticles and 391 nm for silver nanoparticles. Microscopic results confirmed the presence of spherical shapes. The X-ray diffraction pattern demonstrated a face-centered cubic structure. Both nanoparticles had negative zeta potentials and retained colloidal stability in cell culture medium. Catalytic applications were evaluated for 4-nitrophenol reduction and methyl orange degradation reactions by monitoring with UV-visible spectrophotometry. Furthermore, the nanoparticles demonstrated no significant cytotoxicity against human pancreas ductal adenocarcinoma cells (PANC-1) and human colorectal adenocarcinoma cells (HT-29). PEGylation and diallyl disulphide loading of the gold and silver nanoparticles meaningfully reduced the cell viability of both cell lines. Furthermore, diallyl disulphide loading resulted in more cytotoxicity against PANC-1 cells than against HT-29 cells. Additionally, the gold nanoparticles were more cytotoxic than the silver nanoparticles upon diallyl disulphide loading. Interestingly, after PEGylation and diallyl disulphide loading, the silver nanoparticles exhibited acorn-like shapes, while the gold nanoparticles retained spherical shapes. This result suggested that nanoparticles green-synthesised by onion extract have possibilities as nanocatalysts and drug delivery nanocarriers for catalytic and nanomedicine applications.

Environmentally Friendly Synthesis of Au-Te-Clustered Nanoworms via Galvanic Replacement for Wavelength-Selective Combination Cancer Therapy

Au-Te-clustered nanoworms (AuTeNWs) were successfully synthesized under ambient conditions by spontaneous galvanic replacement using Te nanorods as a sacrificial nanotemplate. Along with the gradual replacement and on-surface crystalline Au cluster formation, Te nanotemplates were transformed into a serpentine nanoworm-like morphology. The present strategy was an environmentally friendly method that did not use surfactants to control the surface structure. The synthesized nanoworms exhibited excellent photothermal conversion, photocatalytic efficiencies, and high payloads for thiolated genes and cell-penetrating peptides. According to the visible and near-infrared wavelengths of light, the photodynamic and photothermal therapeutic pathways were dominantly acting, respectively. From this, wavelength-selective combination treatment with gene therapy was successfully accomplished. Taken together, excellent therapeutic effects for in vitro and in vivo mouse models against hepatitis C replicon human hepatocarcinoma were clearly identified by using the present AuTeNWs as a phototherapeutic nanocarrier.

Catalytic System Based on Sub-2 nm Pt Particles and Its Extraordinary Activity and Durability for Oxygen Reduction

Carbon-supported Pt nanoparticles are used as catalysts for a variety of reactions including the oxygen reduction reaction (ORR) key to proton-exchange membrane fuel cells, but their catalytic performance has long been plagued by detachment and sintering. Here we report the in situ growth of sub-2 nm Pt particles on a commercial carbon support via the galvanic reaction between a Pt(II) precursor and a uniform film of amorphous Se predeposited on the support. The residual Se could serve as a linker to strongly anchor the Pt nanoparticles to the carbon surface, leading to a catalytic system with extraordinary activity and durability toward ORR. Even after 20 000 cycles of accelerated durability test, the sub-2 nm Pt particles were still dispersed well on the carbon support and maintained a mass activity more than three-times as high as the pristine value of a commercial Pt/C catalyst.

Synthesis and Thermoelectric Properties of Selenium Nanoparticles Coated with PEDOT:PSS

We synthesized a hybrid nanocomposite comprised of selenium nanoparticles coated with a thin layer of a conductive polymer, poly(3,4-ethylenedioxythiophene), and studied its thermoelectric properties. The conductive polymer layer on the surface of nanoparticles in the composites formed a percolating network running between the stacked nanoparticles, exhibiting an electrical conductivity close to or higher than that of pure polymer. The thermoelectric power factor of the resulting composite was higher than that of individual polymer or selenium nanoparticles. We further increased the electrical conductivity of the composite by thermal annealing, thereby improving the power factor to 15 μW/cmK² which is nine times higher than that of the polymer.

Green synthesis of Se/Ru alloy nanoparticles using gallic acid and evaluation of theiranti-invasive effects in HeLa cells

Methods for the synthesis of nanoparticles (NPs) for biomedical applications ideally involve the use of nontoxic reducing and capping agents, and more importantly, enable control over the shape and size of the particles. As such, we used gallic acid (GA) as both a reducing and a capping agent in a simple and "green" synthesis of stable Se/Rualloy NPs (GA-Se/RuNPs). The diameter and morphology of the Se/Ru alloy NPs were regulated by GA concentration, and the presence of Ru was found to be a key factor in regulating and controlling the size of GA-Se/RuNPs. Moreover, GA-Se/RuNPs suppressed HeLa cell proliferation through the induction of apoptosis at concentrations that were nontoxic in normal cells. Furthermore, GA-Se/RuNPs effectively inhibited migration and invasion in HeLa cells via the inhibition of MMP-2 and MMP-9 proteins. Our findings confirm that bimetallic (Se/Ru) NPs prepared via GA-mediated synthesis exhibit enhanced anticancer effects.

PEG functionalized selenium nanoparticles as a carrier of crocin to achieve anticancer synergism

Schematic representation of crocin extraction from saffron stigmas and possible mechanism of pH based crocin delivery system of PEG-SeNP induced apoptosis in lung cancer cell.

Distinct reactivities on segmented selenium nanorods

We demonstrate a new approach to synthesize several unique nanostructures by tuning the selective reactivities on individual symmetry-breaking segmented selenium nanorods (SBS-SeNRs). The segment-selective reactions from thiolated silane endowed the formation of float-like SBS-SeNR@SiO2 with a silica coating on the t-Se segment. Several other unique nanostructures were further synthesized by applying other selective reactions, such as Se chemical removal and nanogold deposition. Such a segmented nanomaterial of SBS-SeNRs acts as a new chemical template for preparing various segmented nanocomposites.