PEO coated magnetic nanoparticles for biomedical application

Abstract

International audienceThis paper reports on the preparation, characterization and stealthiness of superparamagnetic nanoparticles (magnetite Fe3O4) with a 5 nm diameter and stabilized in water (pH > 6.5) by a shell of water-soluble poly(ethylene oxide) (PEO) chains. Two types of diblock copolymers, i.e., poly(acrylic acid)-b-poly(ethylene oxide), PAA-PEO, and poly(acrylic acid)-b-poly(acrylate methoxy poly(ethyleneoxide)), PAA-PAMPEO, were prepared as stabilizers with different compositions and molecular weights. At pH > 6.5, the negatively ionized PAA block interacts strongly with the positively-charged nanoparticles, thus playing the role of an anchoring block. Aggregates of coated nanoparticles were actually observed by dynamic light scattering (DLS) and transmission electron microscopy (TEM). The hydrodynamic diameter was in the 50-100 nm range and the aggregation number (number of nanoparticles per aggregate) was lying between several tens and hundred. Moreover, the stealthiness of these aggregates was assessed "in vitro" by the hemolytic CH50 test. No response of the complement system was observed, such that biomedical applications can be envisioned for these magnetic nanoparticles. Preliminary experiments of magnetic heating (10 kA/m; 108 kHz) were performed and specific absorption rate varied from 2 to 13 W/g(Fe)

Positively-Charged, Porous, Polysaccharide Nanoparticles Loaded with Anionic Molecules Behave as ‘Stealth’ Cationic Nanocarriers

“…Our study showed an inhibition of complement activation by BSA or DG loading inside NP + , which might be compared to inhibition obtained after long chain of poly(ethylene glycol) (PEG) addition to strong activator nanoparticles, as shown by Van Butsele et al, Aqil et al and Layer et al (48)(49)(50)(51). Indeed, PEG create a steric barrier around particles able to protect against protein adsorption due to a decrease of surface hydrophobicity and a neutralization of surface potential.…”

Physicochemical properties of pH-controlled polyion complex (PIC) micelles of poly(acrylic acid)-based double hydrophilic block copolymers and various polyamines

“…The DHBC polymer poly(acrylic acid)-b-poly(acrylate methoxy poly(ethylene oxide)) (PAA 48 -b-PAMPEO 36 ; M PAA 03,500 g/mol; M PAMPEO 016,300 g/mol; polydispersity index, PDI01.23) was synthesized according to [20]. The neutral chains have a comb-like architecture with pendant polyethylene oxide chains of seven to eight monomers, while the PAA block is linear.…”

Nanostructured silica templated by double hydrophilic block copolymers with a comb-like architecture

“…(Figure 3), according to the procedure of Aqil et al [21]. The polymer polydispersity was determined to be 1.31.…”

“…For a same molecular weight as that of the neutral linear part, the comb block (expected to interact with silica) is shorter and denser than the linear homologue and so, this modification should influence the organic/inorganic interactions ( Figure 2). Moreover, the PAA-b-PAMPEO copolymer is here synthesized quickly by using only one polymerization technique, the RAFT (Reversible Addition Fragmentation chain Transfer) polymerization for the two polymeric blocks and it is easy to control the size of the two blocks separately [21]. In comparison, the synthesis of PAA-b-PEO block copolymers was reported in the literature by either anionic polymerization [22][23][24] or atom transfer radical polymerization (ATRP) [25,26].…”