Dual-Responsive Magnetic Core–Shell Nanoparticles for Nonviral Gene Delivery and Cell Separation

Abstract

IntroductionThere exist two main approaches for the functionalization of nanoparticles (NPs) with polymer chains fixed on the NPs' surface. The "grafting-to" method is performed by utilizing polymers bearing suitable functional end groups (anchor groups), which are able to bind to the surface of the particle. Alternatively, the "grafting-from" approach can be used to obtain core-shell nanoparticles. In this case, the initiating moiety is immobilized on the nanoparticle surface and the polymerization takes place directly from the surface. 1,2 We present the synthesis of core-shell NPs via the grafting-from approach utilizing a dopamine based ATRP initiator. Dopamine is considered to be a robust anchor for iron oxide surfaces in aqueous media. Grafting of 2-(dimethylamino)ethyl methacrylate (DMAEMA) via surface-initiated ATRP yielded dual responsive core-shell NPs being responsive to temperature and pH. Due to the great potential of cationic polymers for non-viral gene delivery the hybrid material was further investigated related to biotechnical applications. The cytotoxicity and the efficiency as transfection reagent were studied under standard conditions and compared to the "gold standard" poly(ethylene imine), PEI.

A poly(ethylene glycol)-brush decorated magnetic polymer for highly specific enrichment of phosphopeptides

“…The molecular weight of degrafted PEG brushes from Fe 3 O 4 @SiO 2 @PEG nanoparticles measured by GPC was 125 400 g mol À1 with a polydispersity index of 1.32. By combining the results from TGA and GPC (described in ESI †), 59,60 the density of the initiator Br on the magnetic nanoparticles is evaluated to be approximately 10.5 initiators per nm 2 and the grafting density of PEG brushes was about 0.79 chains per nm 2 . The successful introduction of functional group (amine, phosphate and titanium ion) was confirmed by z potential measurements (Table S1 †) and X-ray photoelectron spectrometry (XPS) analysis (Table S2 and Fig.…”

Pentablock copolymers of pluronic F127 and modified poly(2-dimethyl amino)ethyl methacrylate for internalization mechanism and gene transfection studies

“…its monomer can be polymerized in differently controlled manners like atom transfer radical polymerization (ATRP), [7][8][9] and reversible addition-fragmentation chain transfer polymerization. 10,11 However, the transfection efficiency and cytotoxicity of PDMAEMA go hand-in-hand with increasing the molecular weight.…”

Preparation of a Magnetic-responsive Polycation with a Tetrachloroferrate Anion

“…Majewski et al 6 have reported the preparation of magnetic-responsive nanoparticles prepared via surface-initiated atom transfer radial polymerization of 2-(N,N-dimethylamino)ethyl methacrylate from Fe 2 O 3 nanoparticles. Dai et al 7 have reported coreshellcorona-type magneticresponsive particles prepared from diblock copolymers composed of poly(acrylic acid) and polystyrene decorated surfaces on iron oxide particles.…”