Here we report the synthesis of nanoparticles based on a conjugated oligomer which is synthesized through Heckcoupling 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 halfmaximal inhibitory concentration (IC 50 ) 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. IC 50 values for camptothecin in the presence of nanoparticles with or without CB7 were significantly reduced in MCF7 and MDA-MB-231 cells. ■ INTRODUCTIONConjugated polymer nanoparticles (CPNs) are highly appealing for various advanced applications such as in vivo imaging, cell labeling, and delivery of therapeutic agents, as well as nanophotonics, owing to their high quantum yields and molar absorptivity, tunable properties, easy functionalization, photostability, and so forth. 1−7 To date, the use of CPNs has been demonstrated successfully in cell imaging, oxygen sensing, drug delivery, and nucleic acid delivery. 8−16 When these nanostructures are judiciously designed, they can be utilized in theranostic applications by combining more than one functionality to deliver therapeutic and imaging agents. 17−21 For the controlled delivery of therapeutic agents to the targets the nanoparticles could also include responsive groups that will respond to stimuli such as pH, oxidation−reduction, and enzymes. However, in the literature, examples are scarce regarding the multifunctional conjugated polymer nanoparticles (CPNs) and even less with conjugated oligomer-based nanoparticles (CONs). 22,23 Recently, Schenning et al. compared the capabilities of conjugated polymer nanoparticles to selfassembled oligomer-based nanoparticles in terms of their fluorescent quantum yields, stabilities, molar absorptivity, guest-holding, and releasing. 24 They demonstrated that oligomer nanoparticles have higher fluorescent quantum yields and comparable stabilities and molar absorptivity, but they release the guest faster than the conjugated polymer nanoparticles. Thus, this feature should be considered for the further design of oligomer-based nanoparticles for theranostic applications. CONs also offer some useful addi...

In the present article, we present a new and convenient optical method for the preparation of self-standing polyelectrolyte multilayer films. This method employs the disassembly of a sacrificial layer stratum composed of five poly(acrylate, merocyanine) PMC/poly(diallyldimethylammonium chloride) PDADMAC bilayers, which is triggered by the irradiation with visible light. This leads to the conversion of the zwitterionic PMC to its neutral isomer poly(acrylate, spiropyran) PSP, whereby the attractive ionic interactions between the neighboring bilayers vanish. The disassembly of the sacrificial layers in deionized water was completed within 47 s, when in-situ monitored at the maximum absorbance of PSP (λ = 360 nm), employing UV/visible spectrometry. Surprisingly, the disassembly duration of the sacrificial layers increased very little with an upper target film composed of 75 PDADMAC/PSS bilayers. The quick release of a thick target film (d ∼ 232 nm) composed of 100 (PDADMAC)/(PSS) bilayers in a large scale (7 × 18 mm(2)) could be ascribed not only to the vanished electrostatic attractive interaction between the layer pairs but also to increased hydrophobicity of the sacrificial layer element due to the photoisomerization of zwitterionic ionic PMC to neutral PSP. The unique advantages of this method as compared to the conventional approaches are demonstrated with the fast release (~2 min) of self-standing film combined with a well-defined, thin sacrificial layer (d ~ 30 nm). Moreover, harsh release conditions are also avoided, which significantly broadens the choice of materials that can be incorporated into the free-standing film.

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.

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 pHdependent 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 realtime 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.

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