Construction of multi-layered white emitting organic nanoparticles by clicking polymers

A series of blue, green and red emitting polymers that are appropriately functionalized with alkyne and azide functional groups have been prepared and clicked together to construct bi-layered and tri-layered white emitting core-shell type nanoparticles. Here the use of these organic hetero-nanoparticles as colour converters to realize a white light-emitting diode platform acquiring a colour quality comparable to the existing phosphor-based ones was also demonstrated. © The Royal Society of Chemistry

High-Stability, High-Efficiency Organic Monoliths Made of Oligomer Nanoparticles Wrapped in Organic Matrix

Oligomer nanoparticles (OL NPs) have been considered unsuitable for solid-state lighting due to their low quantum yields and low temperature stability of their emission. Here, we address these problems by forming highly emissive and stable OL NPs solids to make them applicable in lighting. For this purpose, we incorporated OL NPs into sucrose matrix and then prepared their all-organic monoliths. We show that wrapping the OL NPs in sucrose significantly increases their quantum yield up to 44%, while the efficiency of their dispersion and direct solid-film remain only at ∼6%. We further showed ∼3-fold improved temperature stability of OL NP emission within these monoliths. Our experiments revealed that a physical passivation mechanism is responsible from these improvements. As a proof-of-concept demonstration, we successfully employed these high-stability, high-efficiency monoliths as color converters on a blue LED chip. Considering the improved optical features, low cost, and simplicity of the presented methodology, we believe that this study holds great promise for a ubiquitous use of organic OL NPs in lighting and possibly in other photonic applications. © 2016 American Chemical Society

pH-Responsive Near-Infrared Emitting Conjugated Polymer Nanoparticles for Cellular Imaging and Controlled-Drug Delivery

Cataloged from PDF version of article.In this article, pH-responsive near-infrared emitting conjugated polymer nanoparticles (CPNs) are prepared, characterized, and their stabilities are investigated under various conditions. These nanoparticles have capacity to be loaded with water insoluble, anticancer drug, camptothecin (CPT), with around 10% drug loading efficiency. The in vitro release studies demonstrate that the release of CPTs from CPNs is pH-dependent such that significantly faster drug release at mildly acidic pH of 5.0 compared with physiological pH 7.4 is observed. Time and dose-dependent in vitro cytotoxicity tests of blank and CPT-loaded nanoparticles are performed by real-time cell electronic sensing (RT-CES) assay with hepatocellular carcinoma cells (Huh7). The results indicate that CPNs can be effectively utilized as vehicles for pH-triggered release of anticancer drugs. (c) 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 114-12

Red emitting cucurbituril-capped, pH-responsive conjugated oligomer-based nanoparticles for drug delivery and cellular Imaging

Cataloged from PDF version of article.Here we report the synthesis of nanoparticles based on a conjugated oligomer which is synthesized through Heck-coupling of divinylfluorene and dibromobenzothiodiazole monomers. These water dispersible nanoparticles emit in the region of red tailing to the near-infrared region of the spectrum with high fluorescent quantum yield and brightness. The nanoparticles were found to be stable in water for a prolonged time without forming any aggregates and could carry camptothecin, an anticancer drug with high loading efficiency. MTT cell viability studies performed with breast cancer cell lines showed that half-maximal inhibitory concentration (IC50) values of nanoparticles for MCF7 and MDA-MB-231 were 44.7 μM and 24.8 μM, respectively. In order to further decrease the cytotoxicity and increase the stability of nanoparticles, amine groups were disguised by capping with cucurbit[7]uril (CB7). Drug release studies showed that drugs were released at low pH (at 5.0) faster than physiological pH (7.4) confirming the pH-responsive nature of the nanoparticles. On the other hand, CB7-capped drug-loaded nanoparticles regulated the release rate by providing slower release at pH 7.4 than the nanoparticles in the absence of CB7s. IC50 values for camptothecin in the presence of nanoparticles with or without CB7 were significantly reduced in MCF7 and MDA-MB-231 cells. © 2014 American Chemical Society

Molecular interactions driving the layer-by-layer assembly of multilayers

This article presents an overview of the different types of intermolecular interactions behind the fabrication of multilayer assemblies using the layer-by-layer (LbL) assembly approach. It comments on the potential impact of each type of intermolecular interaction and materials assembled through them on the development of advanced functional systems or devices for several emerging applications. The discussion begins with a brief overview of the most commonly used bottom-up methods to modify surfaces and fabricate functional multilayer thin films, with a special focus on their main advantages and disadvantages.This work received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement no. REGPOT-CT2012-316331-POLARIS. The work was also funded by FEDER through the Competitive Factors Operational Program (COMPETE) and by National funds through the Portuguese Foundation for Science and Technology (FCT) in the scope of the projects PTDC/FIS/115048/2009 and PTDC/CTM-BIO/1814/2012. The authors gratefully acknowledge Dr. Luca Gasperini (3B's Research Group, University of Minho, Portugal) for his help with the figures