Up-converting ß-NaY0.8[Yb0.18Er0.02]F4 nanoparticles coated by superparamagnetic γ-Fe2O3 nanosatellites: elaboration, characterization and in vitro cytotoxicity.

Current biomedical imaging techniques are vital for the diagnosis of various diseases. They are related to the development of multimodal probes encompassing all the functionalities required for comprehensive imaging. In this context, we applied a simple and reproducible wet synthesis route to produce such probes. This method allowed us to prepare about 100 nm sized lanthanide-doped yttrium fluoride nanoparticles ß-NaY0.8[Yb0.18Er0.02]F4, coated with about 10 nm sized iron oxide γ-Fe2O3 nanocrystals. By this way, the built granular hetero-nanostructures combine desirable up-converting photoluminescence (the core) and superparamagnetic properties (the satellites), enabling dual optical and magnetic resonance imaging applications. Through citrate ligand grafting, the designed core-satellite particles formed stable aqueous colloids, which are valuable for biomedical applications. Optical spectroscopy and confocal microscopy revealed their capability for sustained visible light emission (predominantly green) upon near-infrared excitation (980 nm). Additionally, based on XTT assays, when incubated for 24 hours with mammalian healthy or cancer cells, even at doses as high as 0.1 mg mL-1 (milligrams of particles), they did not induce significant cytotoxicity. The measured body temperature magnetization of the engineered nanoconstructs was found to be about 10 emu g-1 (grams of particles) at 1.5 T, which is high enough to use them as positive or negative contrast magnetic resonance agents in the clinic, as confirmed by relaxometry measurements in Milli-Q water. This result underscores their promising biomedical utility as bimodal probes for optical and magnetic imaging.

Multi-functionalization of lithographically designed gold nanodisks by plasmon-mediated reduction of aryl diazonium salts.

Plasmon-driven surface functionalization of nanoparticles is receiving increasing attention as it allows locally tailored chemical reactivity to be generated on the nanoparticle surface. The extension to surface multi-functionalization still represents a major breakthrough in chemistry. We address this issue by triggering regiospecific surface double-functionalization under plasmon excitation, using diazonium salts as surface functionalization agents.

Correction: Quantum dot-imprinted polymers with size and shell-selective recognition properties.

Correction for 'Quantum dot-imprinted polymers with size and shell-selective recognition properties' by S. Gam-Derouich et al., Chem. Commun., 2015, DOI: 10.1039/c5cc05203c.

Quantum dot-imprinted polymers with size and shell-selective recognition properties.

The emergence of nanotechnology has stimulated a great deal of research to detect engineered nanoparticles spread out in the environment. We address this issue here by designing quantum dot-imprinted polymers for the speciation of nanoparticles based on their size, shape and surface chemistry.