L'acide polymethacrylique est thermosensible en solvant organique

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Recent insights in magnetic hyperthermia: From the “hot-spot” effect for local delivery to combined magneto-photo-thermia using magneto-plasmonic hybrids

International audienceMagnetic hyperthermia which exploits the heat generated by magnetic nanoparticles (MNPs) when exposed to an alternative magnetic field (AMF) is now in clinical trials for the treatment of cancers. However, this thermal therapy requires a high amount of MNPs in the tumor to be efficient. On the contrary the hot spot local effect refers to the use of specific temperature profile at the vicinity of nanoparticles for heating with minor to no long-range effect. This magneto-thermal effect can be exploited as a relevant external stimulus to temporally and spatially trigger drug release.In this review, we focus on recent advances in magnetic hyperthermia. Indirect experimental proofs of the local temperature increase are first discussed leading to a good estimation of the temperature at the surface (from 0.5 to 6 nm) of superparamagnetic NPs. Then we highlight recent studies illustrating the hot-spot effect for drug- release. Finally, we present another recent strategy to enhance the efficacity of thermal treatment by combining photothermal therapy with magnetic hyperthermia mediated by magneto-plasmonic nanoplatforms

Magnetic Nanoparticles Create Hot Spots in Polymer Matrix for Controlled Drug Release

Herein, original magnetic drug delivery nanomaterials for cancer therapy are developed and compared, with the purpose to show active control over drug release by using an alternative magnetic field (AMF). The rationale is to combine polymers and superparamagnetic nanoparticles to trigger such drug release under AMF. Two magnetic nanosystems are thus presented: magnetic nanogels made of thermosensitive and biocompatible polymers and core-shell nanoparticles with a magnetic core and a molecularly imprinted polymer as shell. Both encapsulate doxorubicin (DOX) and the DOX controlled release was investigated in vitro and in cells under AMF excitation. It confirms that the local heat profile at the vicinity of the iron oxide core can be used for the DOX controlled release. It also shows that both nanosystems help delivering more DOX inside the cells compared to internalization of free DOX. Finally, the DOX intracellular release could be remotely triggered under AMF, in athermal conditions, thus enhancing DOX cytotoxicity

Gélification physique de copolymères AB alternés composés d'unités vinylphénol et maléimide: coopération entre les groupes pendants phénol et alkyle incorporés avec précision.

International audienceA series of alternating copolymers consisting of vinyl phenol and n-alkyl maleimide was synthesized via radical copolymerization of a protected styrene derivative with a functional maleimide monomer followed by the deprotection. The copolymers carrying long alkyl pendant such as C12H25-or C18H37-chains on the maleimide unit showed UCST-type thermal response in aromatic solvents and organogels were specifically formed upon cooling of the fluid solution prepared at higher temperature. Hydrogen bonding of the phenol units is crucial for the gelation and the gelation temperature and stiffness were tuneable by varying concentration, solvent and polymerization degree. Analyses by 1 H-NMR, linear rheology, WAXD, SANS and cryo-TEM gave the picture of vermicular self-assembled nano-objects formed through segregated and hydrogen-bonded packing by the precisely incorporated two units in alternating sequence

Magnetic Nanoparticles Create Hot Spots in Polymer Matrix for Controlled Drug Release

International audienceHerein, original magnetic drug delivery nanomaterials for cancer therapy are developed and compared, with the purpose to show active control over drug release by using an alternative magnetic field (AMF). The rationale is to combine polymers and superparamagnetic nanoparticles to trigger such drug release under AMF. Two magnetic nanosystems are thus presented: magnetic nanogels made of thermosensitive and biocompatible polymers and core-shell nanoparticles with a magnetic core and a molecularly imprinted polymer as shell. Both encapsulate doxorubicin (DOX) and the DOX controlled release was investigated in vitro and in cells under AMF excitation. It confirms that the local heat profile at the vicinity of the iron oxide core can be used for the DOX controlled release. It also shows that both nanosystems help delivering more DOX inside the cells compared to internalization of free DOX. Finally, the DOX intracellular release could be remotely triggered under AMF, in athermal conditions, thus enhancing DOX cytotoxicity

Doxorubicin Intracellular Remote Release from Biocompatible Oligo(ethylene glycol) Methyl Ether Methacrylate-Based Magnetic Nanogels Triggered by Magnetic Hyperthermia

International audienceHybrid nanogels, composed of thermoresponsive polymers and superparamagnetic nanoparticles (MNPs) are attractive nanocarriers for biomedical applications, being able – as polymer matrix – to uptake and release high quantities of chemotherapeutic agents and – as magnetic nanoparticles – to heat when exposed to an alternative magnetic field (AMF), better known as magnetic hyperthermia. Herein, biocompatible, pH-, magnetic-and thermo-responsive nanogels, based on oligo (ethylene glycol) methacrylate monomers 2 (OEGMAs) and methacrylic acid co-monomer (MAA) were prepared by conventional precipitation radical co-polymerization in water, post-assembled by complexation with iron oxide magnetic nanoparticles (MNPs) of maghemite (-Fe 2 O 3) and loaded with an anticancer drug (doxorubicin – DOX), for remotely controlled drug release by " hot-spot " , as an athermal magnetic hyperthermia strategy against cancer. These nanogels, noted MagNanoGels, with a hydrodynamic diameter from 328 to 460 nm, as a function of MNPs content, have a swelling-deswelling behavior at their volume phase temperature transition (VPTT) around 47 °C in a physiological medium (pH 7.5), which is above the human body temperature (37 °C). Applying an alternative magnetic field increases twice the release of DOX, while no macroscopic heating was recorded. This enhanced drug release is due to a shrinking of the polymer network by local heating, as illustrated by the MagNanoGels size decrease under AMF. In cancer cells, not only the DOX-MagNanoGels internalize DOX more efficiently than free DOX, but also DOX intracellular release can be remotely triggered under AMF, in athermal conditions, thus enhancing DOX cytotoxicity