A novel hybrid nanocomposite formed of carboxylated Nano Graphene Oxide (c-NGO), highly densely decorated by monodisperse citrate-coated Au nanoparticles (c-NGO/Au NPs), is synthesized and thoroughly characterized for photothermal applications. A systematic investigation of the role played by the synthetic parameters on the Au NPs decoration of the c-NGO platform is performed, comprehensively studying spectroscopic and morphological characteristics of the achieved nanostructures, thus elucidating their still not univocally explained synthesis mechanism. Remarkably, the Au NPs coating density of the c-NGO sheets is much higher than state-of-the-art systems with analogous composition prepared with different approaches, along with a higher NPs size dispersion. A novel theoretical approach for estimating the average number of NPs per sheet, combining DLS and TEM results, is developed. The assessment of the c-NGO/Au NPs photothermal activity is performed under continuous wave (CW) laser irradiation, at 532 nm and 800 nm, before and after functionalization with PEG-SH. c-NGO/Au NPs composite behaves as efficient photothermal agent, with a light into heat conversion ability higher than that of the single components. The c-NGO/Au NPs compatibility for photothermal therapy is assessed by in vitro cell viability tests, which show no significant effects of c-NGO/Au NPs, as neat and PEGylated, on cell metabolic activity under the investigated conditions. These results demonstrate the great potential held by the prepared hybrid nanocomposite for photothermal conversion technologies, indicating it as particularly promising platform for photothermal ablation of cancer cells

A novel hybrid nanocomposite, formed of Reduced Graphene Oxide (RGO) flakes surface functionalized with 1-pyrene carboxylic acid (PCA) and decorated by Au nanoparticles (NPs), has been synthesized for the electrochemical detection of the miRNA-221 cancer biomarker. The hybrid material has been prepared by a facile approach, relaying on the in situ synthesis of the Au NPs onto the PCA carboxylic groups in presence of 3,4-dimethylbenzenethiol (DMBT) and NaBH. The short aromatic thiol DMBT acts as reducing and coordinating agent, and hence, enables the dispersion of the nanocomposite in organic solvents. Concomitantly, DMBT favors the non-covalent anchoring of the Au NPs onto RGO, potentially allowing an efficient particle/RGO and interparticle ?-? mediated electron coupling, which enhances the electron conductivity and charge transfer. PCA-RGO flakes, densely and uniformly decorated with a multilayer network of DMBT-coated Au NPs, 2.8 ± 0.6 nm in size, have been obtained, overcoming limitations previously reported for similar hybrid materials in terms of coating density and NP size distribution. Screen-Printed Carbon Electrodes (SPCEs), modified by the hybrid material and then functionalized with a thiolated DNA capture probe, have been tested for the determination of miRNA-221 in spiked human serum samples.

Thermoelectric application of conjugated polymers has recently become a subject of scientific interest. This is due to the peculiar features of these organic materials, such as low cost, safety, abundance of atomic components, and easy processing, which make them an interesting alternative to inorganic materials commonly used for this application in the room temperature range, i.e., tellurides derivatives, such as Bi2Te3 and Sb2Te3. Two are the main drawbacks of organic materials employment: the first is their poor thermoelectrical performance, which is still low in comparison with inorganic benchmark, the second is the scarcity of stable and easy-to-dope n-type polymers. In order to address the first issue, we tried to obtain a further and crucial efficiency improvement, developing a nanocomposite embedding inorganic nanoparticles in a matrix of conjugated polymer. A hybrid film of poly(3,4-ethylenedioxithiophene):Tosylate (PEDOT:Tos) and Mn3O4 nanoparticles have been achieved through a novel strategy, involving nanoparticle functionalization and in situ polymerization. The purpose is to enable energy filtering thanks to the presence of the NPs so as to extend this beneficial effect already been observed in inorganic semiconductor to polymers. Our study indicates a new path to obtain PEDOT-based nanocomposite and enlightens the peculiar behaviour of this hybrid material. Copyright © 2017 American Scientific Publishers All rights reserved.