Thermoresponsive polymer brush-functionalized magnetic manganite nanoparticles for remotely triggered drug release

Abstract

International audienceA thermoresponsive hybrid system for drug delivery purposes is designed by modifying the surface of silica-coated magnetic lanthanum strontium manganite nanoparticles with block copolymers following a non-covalent approach. Block copolymers containing a short poly(L-lysine) segment and a polyether segment of varying composition are adsorbed through electrostatic interactions between positively charged lysine units and negatively charged SiO− groups at the silica surface, giving rise to mixed polyether brushes with a good control over the chain surface density and thickness of the polymer layer. The thermoresponsiveness of the assemblies is controlled by the ethylene oxide/propylene oxide ratio in the polymer brush and the corresponding LCST of the polyether blocks. Important parameters like the aggregation temperature of the particles can be finely adjusted by modifying this ratio. The polarity of the polymer layer can also be varied to maximize the encapsulation efficiency of a moderately hydrophobic drug like doxorubicin. Drug release experiments are performed by taking advantage of the ac magnetically induced heating properties of the magnetic core to speed up the release of doxorubicin owing to structural changes within the polyether brush

Smart micro/nanoparticles in stimulus-responsive drug/gene delivery systems

“…117 An external magnetic field can also enhance cellular uptake of NPs. 119 Louguet et al 118 developed silica-coated MagNPs functionalized with thermo-sensitive block copolymer brushes with an LCST transition. Application of an AC-magnetic field induced heat generation by the magnetic core and enhancement of the triggered release of the drug (DOX) due to conformational changes occurring in the brushes (Fig.…”

Stimuli-sensitive intrinsically disordered protein brushes

“…Some polymer brushes are environment-sensitive, with specific changes in solvent conditions triggering their expansion or collapse. These materials can be used to exert dynamic control over the spatial presentation of regulatory peptides and are under investigation for many applications 4,5 , including sensors 6 , flow valves 7 and controlled drug release systems 8 . However, because these brushes are almost universally constructed from synthetic polymers, they are frequently somewhat heterogeneous and are challenging to modify at specific monomeric positions along the chain.…”

Smart Stimuli-Responsive Nano-sized Hosts for Drug Delivery

“…There are two potential solutions to this problem, the fi rst being in vivo thermal monitoring via thermometry, which is invasive [ 88 ]. The second is to utilize the MNP's reliance upon thermal conditions; specifi cally, choosing materials possessing Curie temperatures that can mimic physiological conditions (i.e., lanthanum strontium manganese oxide MNPs) [ 89 ].…”