Two-Photon Fluorescence Imaging and Bimodal Phototherapy of Epidermal Cancer Cells with Biocompatible Self-Assembled Polymer Nanoparticles

We have developed herein an engineered polymer-based nanoplatform showing the convergence of two-photon fluorescence imaging and bimodal phototherapeutic activity in a single nanostructure. It was achieved through the appropriate choice of three different components: a β-cyclodextrin-based polymer acting as a suitable carrier, a zinc phthalocyanine emitting red fluorescence simultaneously as being a singlet oxygen (1O2) photosensitizer, and a tailored nitroaniline derivative, functioning as a nitric oxide (NO) photodonor. The self-assembly of these components results in photoactivable nanoparticles, approximately 35 nm in diameter, coencapsulating a multifunctional cargo, which can be delivered to carcinoma cells. The combination of steady-state and time-resolved spectroscopic and photochemical techniques shows that the two photoresponsive guests do not interfere with each other while being enclosed in their supramolecular container and can thus be operated in parallel under control of light stimuli. Specifically, two-photon fluorescence microscopy allows mapping of the nanoassembly, here applied to epidermal cancer cells. By detecting the red emission from the phthalocyanine fluorophore it was also possible to investigate the tissue distribution after topical delivery onto human skin ex vivo. Irradiation of the nanoassembly with visible light triggers the simultaneous delivery of cytotoxic 1O 2 and NO, resulting in an amplified cell photomortality due to a combinatory effect of the two cytotoxic agents. The potential of dual therapeutic photodynamic action and two-photon fluorescence imaging capability in a single nanostructure make this system an appealing candidate for further studies in biomedical research. © 2014 American Chemical Society

A “green” strategy to construct non-covalent, stable and bioactive coatings on porous MOF nanoparticles

AbstractNanoparticles made of metal-organic frameworks (nanoMOFs) attract a growing interest in gas storage, separation, catalysis, sensing and more recently, biomedicine. Achieving stable, versatile coatings on highly porous nanoMOFs without altering their ability to adsorb molecules of interest represents today a major challenge. Here we bring the proof of concept that the outer surface of porous nanoMOFs can be specifically functionalized in a rapid, biofriendly and non-covalent manner, leading to stable and versatile coatings. Cyclodextrin molecules bearing strong iron complexing groups (phosphates) were firmly anchored to the nanoMOFs' surface, within only a few minutes, simply by incubation with aqueous nanoMOF suspensions. The coating procedure did not affect the nanoMOF porosity, crystallinity, adsorption and release abilities. The stable cyclodextrin-based coating was further functionalized with: i) targeting moieties to increase the nanoMOF interaction with specific receptors and ii) poly(ethylene glycol) chains to escape the immune system. These results pave the way towards the design of surface-engineered nanoMOFs of interest for applications in the field of targeted drug delivery, catalysis, separation and sensing.</jats:p

Thermostimulable Wax@SiO2 Core-Shell Particles

We propose a new synthesis pathway without any sacrificial template to prepare original monodisperse thermo-7 responsive capsules made of a wax core surrounded by a silica shell. Under heating, the inner wax expands and the shell 8 breaks, leading to the liquid oil release. Such capsules that allow triggered deliverance provoked by an external stimulus 9 belong to the class of smart materials. The process is based on the elaboration of size-controlled emulsions stabilized by 10 particles (Pickering emulsions) exploiting the limited coalescence phenomenon. Then the emulsions are cooled down 11 and the obtained suspensions are mineralized by the hydrolysis and condensation of a monomer at the wax-water 12 interface, leading to the formation of capsules. The shell break and the liquid oil release are provoked by heating above 13 the wax melting temperature. We characterize the obtained materials and examine the effect of processing parameters 14 and heating history. By an appropriate choice of the wax, the temperature of release can easily be tuned