Graphene/Carbon Dot Hybrid Thin Films Prepared by a Modified Langmuir-Schaefer Method

The special electronic, optical, thermal, and mechanical properties of graphene resulting from its 2D nature, as well as the ease of functionalizing it through a simple acid treatment, make graphene an ideal building block for the development of new hybrid nanostructures with well-defined dimensions and behavior. Such hybrids have great potential as active materials in applications such as gas storage, gas/liquid separation, photocatalysis, bioimaging, optoelectronics, and nanosensing. In this study, luminescent carbon dots (C-dots) were sandwiched between oxidized graphene sheets to form novel hybrid multilayer films. Our thin-film preparation approach combines self-assembly with the Langmuir-Schaefer deposition and uses graphene oxide nanosheets as template for grafting C-dots in a bidimensional array. Repeating the cycle results in a facile and low-cost layer-by-layer procedure for the formation of highly ordered hybrid multilayers, which were characterized by photoluminescence, UV-visible, X-ray photoelectron, and Raman spectroscopies, as well as X-ray diffraction and atomic force microscopy.</p

Synthesis, characterization and evaluation of aqueous Zn-based quantum dots for bioapplications

Semiconducting nanoparticles called quantum dots (Qds) present unique optoelectronic properties based on their extremely small size, composition, and spherical shape, which make them suitable for use as diagnostic and theranostic agents in biological samples. The main scope of the fabrication of Qds is real-time diagnosis, therapy, drug delivery, and in vitro and in vivo tracking, presenting strong resistance to photobleaching. In this work, quantum dots such as ZnO, ZnSe, ZnS, and doped ZnS : Mn and ZnS : Cd were developed via a simple sol-gel synthesis in an aqueous solution. Morphological, structural, and optical characterizations were investigated. Moreover, an in vitro biological evaluation of Qds was performed. The results indicate that the photoluminescence is enhanced after doping ZnS Qds with Mn2+ and Cd2+. Qds have been synthesized for use as fluorescent agents for real-time monitoring in bio-applications. © 2022 The Royal Society of Chemistry

Bimetallic gold-platinum nanoparticles as a drug delivery system coated with a new drug to target glioblastoma

A drug delivery nanosystem of noble bimetallic nanoparticles (NPs) which consists of Au NPs capped with Pt NPs (Au@Pt NPs) is constructed and functionalised with a quinazoline based small molecule (Au@Pt@Q NPs), acting as a theranostic agent against glioblastoma. Two different hydrothermal synthetic procedures for bimetallic Au@Pt NPs are presented and the resulting nanostructures are fully characterised by means of spectroscopic and microscopic methods. The imaging and targeting capacity of the new drug delivery system is assessed through fluorescent optical microscopy and cytotoxicity evaluations. The constructed Au@Pt NPs consist a monodispersed colloidal solution of 25 nm with photoluminescent, fluorescent and X-Ray absorption properties that confirm their diagnostic potential. Haemolysis testing demonstrated that Au@Pt NPs are biocompatible and fluorescent microscopy confirmed their entering the cells. Cytological evaluation of the NPs through MTT assay showed that they do not inhibit the proliferation of control cell line HEK293, whereas they are toxic in U87MG, U251 and D54 glioblastoma cell lines; rendering them selective targeting agents for treating glioblastoma. © 202

Controlled deposition of fullerene derivatives within a graphene template by means of a modified Langmuir-Schaefer method

The scientific and technological potential of graphene's includes the development of light, open 3D hybrid structures with high surface area, tunable pore size and aromatic functionalities. Towards this aim, we describe a scalable and low-cost bottom-up approach that combines self-assembly and Langmuir-Schaefer deposition for the production of fullerene-intercalated graphene oxide hybrids. This method uses graphene oxide (GO) nanosheets as template for the attachment of two types of fullerene derivatives (bromo-fullerenes, C60Br24 and fullerols, C-60(OH)(24)) in a bi-dimensional arrangement, allowing a layerby-layer growth with control at nanoscale. Our film preparation approach relies on a bottom-up process that includes the formation of a hybrid organo-graphene Langmuir film, which is transferred onto a substrate and then brought in contact with C-60(OH)(24) molecules in solution to induce self-assembly. In the case of grafting C60Br24 molecules into graphene a further modification of the GO platelets was performed by bringing the surface of the transferred GO Langmuir film in contact with a second amino surfactant solution. Repeating these deposition cycles, pillared structures were fabricated in thin films form. These fullerene-based hybrid thin films were characterized by Raman and X-ray photoelectron (XPS) spectroscopies, X-ray diffraction (XRD), Atomic Force Microscopy (AFM) and contact angle measurements. (C) 2018 Elsevier Inc. All rights reserved