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[en] Highlights: • The dissolution model of nanoparticles was established. • The size-dependent dissolution thermodynamics were derived. • The influence regularities of nano-Cu dissolved in dilute acid were discussed. • The dissolution behavior of nanoparticles could be explained by the dissolution model. • It provided guidance for the preparations and applications of the nanomaterials.
[en] A general and practical chemiluminescence (CL) biosensing platform for detection of tumor marker prostate-specific antigen (PSA) as a model analyte was developed for the first time based on the excellent catalytic performance of bimetallic Au-Ag core-shell nanoparticales ([email protected] NPs) on luminol-K3Fe(CN)6 CL system. The [email protected] NPs were synthesized by a simple and green aqueous phase successive reduction method. The prepared [email protected] NPs with remarkable synergistic catalytic activity effect could significantly catalyze luminol-K3Fe(CN)6 CL reaction to produce a great CL enhancement. Based on this synergistic catalytic activity, a luminol-K3Fe(CN)6[email protected] NPs CL system combined with immunoassay was designed for the sensitive detection of PSA. In this protocol, the [email protected] NPs were modified with anti-PSA-antibody ([email protected] NPs) to specifically capture target molecules PSA. In the presence of PSA, a non-competitive immunoreaction occurred between [email protected] NPs and PSA to form an immnunonanoshperes ([email protected] NPs). The results show that the CL catalytic ability of the immnunonanospheres decreased with the PSA concentration increasing. And the quenching degree of CL signals is proportional to the logarithm of PSA concentration in the range of 0.1 pg mL−1–100.0 ng mL−1. Thanks to the fine performance of the [email protected] NPs, the detection limit of the method is down to 0.047 pg mL−1 (S/N = 3). Moreover, the applicability of the present method was successfully applied for PSA determination in human serum samples with recoveries of 86.1–112.5%, demonstrating great promise for application in biochemical analysis.
[en] When considering the safety of ingested nanomaterials, it is important to quantitate their transfer across intestinal cells; however, little information exists about the effects of nanomaterial size or exposure side (apical versus basolateral epithelial surface) on nanomaterial transfer. Here, we examined cellular internalization and transcellular transport, and the effects of nanomaterials on Caco-2 monolayers after apical or basolateral exposure to Ag or Au nanoparticles with various sizes. After apical treatment, both internalization and transfer to the basolateral side of the monolayers were greater for smaller Ag nanoparticles than for larger Ag nanoparticles. In contrast, after basolateral treatment, larger Ag nanoparticles were more internalized than smaller Ag nanoparticles, but the transfer to the apical side was greater for smaller Ag nanoparticles. Au nanoparticles showed different rules of internalization and transcellular transport compared with Ag nanoparticles. Furthermore, the paracellular permeability of the Caco-2 monolayers was temporarily increased by Ag nanoparticles (5 μg/mL; diameters, ≤10 nm) following basolateral but not apical exposure. We conclude that the internalization, transfer, and effects of nanomaterials in epithelial cell monolayers depend on the size and composition of nanomaterials, and the exposure side. - Highlights: • Ag and Au nanoparticles can transfer across Caco-2 monolayers. • Cellular uptake of nanoparticles change between apical and basolateral exposure. • Basolateral Ag nanoparticle exposure increases the permeability of Caco-2 monolayers.
[en] Highlights: • Yeast cells were used as carriers for hosting metal nanoparticles via in situ metal ion reduction. • Yeast cells carrying metal nanoparticles are “green” hierarchical particle systems without any chemical stabilizers or dispersants. • Ag nanoparticles with size of about 4 nm were produced inside yeast cells by UV illumination. • Ag nanoparticles with size of about 9 nm were produced in the cell envelope by chemical reduction. • Pd nanoparticles with size of about 11 nm were almost evenly distributed in every parts of yeast cells.
[en] Nitrilimine cycloadditions to ethylenes, acetylenes, and activated nitriles have been exploited in the presence of catalytic amounts of oleic-acid-coated iron oxide nanoparticles (diameter = 11.9 ± 1.0 nm). The reactions were fully regioselective with monosubstituted ethylenes and ethyl cyanoformiate, while mixtures of cycloadducts were obtained in the presence of methyl propiolate. The intervention of iron oxide nanoparticles allowed carrying out the cycloadditions at milder conditions compared to the metal-free thermal processes. A labile intermediate has been proposed to explain this behavior. .
[en] In this study, green synthesis of silver nanoparticles (AgNPs) and silver-montmorillonite (MMT) nanocomposites (Ag/MMT) were carried out using two local plants from Iran (Ocimum basilicum L and Teucrium Polium L). The biomolecules presenting in the plant extracts acted as the reducing and capping agents. The average size of the synthesized AgNPs, using OB and TP plant extracts were around 80 nm and 20 nm, respectively. In addition, the nanoparticle sizes were further decreased using MMT as substrate, to 70 nm and 15 nm for OB and TP plant extracts, respectively. Finally, high antibacterial efficiency against E. coli and S. aureus pathogens as well as the appropriate cytotoxicity against HEP G2 cells were observed from the biosynthesized AgNPs. The present work is eco-friendly benign and can be used for large-scale fabrication of AgNPs. (paper)
[en] Highlights: • A triboelectric biosensor is developed for the self-powered detection of thrombin. • The selective recognition of thrombin is achieved by using aptamer. • The change in the electrical output upon sensing is resulted from the changes in the surface potential. • The triboelectric biosensor achieves a high detection sensitivity of 0.41 nM. • Thrombin detection is also directly demonstrated via an array of LED lights. An aptamer-based triboelectric biosensor is developed for a highly specific, label-free and self-powered detection of thrombin. For the first time, intermolecular recognition interactions are used to develop a selective nanosensor based on triboelectric effect. Positively charged Au nanoparticles (Au NPs+) with large difference in triboelectric polarity and work function are assembled onto Al film to increase the electrical output of triboelectric nanogenerators (TENG). Modification of anti-thrombin aptamers on the Au NPs+-assembled TENG affords the triboelectric nanosensor highly selective toward thrombin, even in clinical samples because of specific binding affinity between aptamers and thrombin unlike random DNA-modified TENGs with undetectable response. A 0.41 nM limit of detection is achieved, which is directly demonstrated by the number of commercial LED lights without any supporting equipment such as power source and electrometer. Our study demonstrates an innovative and unique approach toward the self-powered and label-free detection of thrombin for rapid and simple in-field analysis.
[en] A large area nano-duplex-imprint technique is presented in this contribution using natural cicada wings as stamps. The glassy wings of the cicada, which are abundant in nature, exhibit strikingly interesting nanopillar structures over their membrane. This technique, with excellent performance despite the nonplanar surface of the wings, combines both top-down and bottom-up nanofabrication techniques. It transitions micro-nanofabrication from a cleanroom environment to the bench. Two different materials, dicing tape with an acrylic layer and a UV optical adhesive, are used to make replications at the same time, thus achieving duplex imprinting. The promise of a large volume of commercial manufacturing of these nanostructure elements can be envisaged through this contribution to speeding up the fabrication process and achieving a higher throughput. The contact angle of the replicated nanowell arrays before and after oxygen plasma was measured. Gold nanoparticles (50 nm) were used to test how the nanoparticles behaved on the untreated and plasma-treated replica surface. The experiments show that promising nanoparticle self-assembly can be obtained. (paper)
[en] Highlights: • Electrodeposition of PEDOT polymers with alkyne groups toward platform surfaces • Use of the Huisgen reaction as post-functionalization • Different hydrophobic substituents tested • Influence of the grafting of nanoparticles before post-functionalization • The nanoparticles allow reaching superhydrophobic properties. Surface post-functionalization is one of the key modification pathways leading to superhydrophobic surfaces. The functionalization is deeply linked to the functionalizable area and the number of functionalizable groups. By grafting functional nanoparticles onto surfaces it is possible to dramatically increase both the area and the number of functionalizable groups. In this work, we report the elaboration of platform surfaces for direct functionalization by grafting nanoparticles and functionalization using the Huisgen reaction. The surfaces were functionalized with various hydrophobic side chain including alkyl, aryl and perfluorinated chains. The modified surfaces have enhanced hydrophobic, parahydrophobic or superhydrophobic properties. The surfaces were investigated for their wettability, morphology and roughness. This work shows that the use of nanoparticles to increase functionalizable surface area can highly enhance surface hydrophobic properties.