A novel solventless coating method to graft low-molecular weight polyethyleneimine on silica fine powders

Abstract

ABSTRACT:The overall objective of the present study was to modulate the surface characteristics of aerogel-like submicron and nanometric particles by coating them with polyethyleneimine (PEI) to suit specific biological applications. A new process for the covalent grafting of low-molecular weight PEI chains has been described, based on the use of compressed CO 2 as the initiator of the ring opening polymerization of the ethyleneimine monomer, which was performed in the presence of silica particles. Coating was done at low pressure and temperature and in the absence of any organic solvent. Obtained materials were compared with a product prepared following the standard soaking procedure for PEI coating. Materials were characterized regarding composition, structure, surface charge, particle size, morphology, and drug release. The developed process led to the covalent grafting of low-molecular weight PEI on the silica surface, which conferred an increased thermal stability for the coating and low cytotoxicity to the particles.

Green and Solvent-Free Supercritical CO2-Assisted Production of Superparamagnetic Graphene Oxide Aerogels: Application as a Superior Contrast Agent in MRI

“…48 Indeed, a facile scCO 2 strategy has been previously developed in our laboratory to functionalize aerogel magnetic NPs with pei polymer, with the objective of increasing biocompatibility and, simultaneously, controlling drug release. 28 The pei random branched structure is produced by the CO 2 -catalyzed exothermic polymerization of the aziridine monomer in the supercritical medium. This method was applied in this work to covalently conjugate the polymer to the aerogels' surface (Figure 9).…”

“…Next, the use of polyethylenimine (pei), a widely employed coating agent in the pharmaceutical industry, is investigated to modulate the behavior of the composite in water. 28 ■ MATERIALS AND METHODS Materials. GO sheets were purchased from Graphenea Inc. (Spain), supplied as a stable dispersion in water with a concentration of 4 mg•mL −1 .…”

“…Finally, the use of the ex situ procedure circumvents the drawback of NPs’ uncontrolled aggregation during growth, since it has been proven that only the controlled clustering of the magnetic NPs results in a considerable increase of MRI efficiency. − Eventually, the use of coating agents has also been proposed to control NP clustering. , Accordingly, this study first explores the use of small ligands, such as citrate, to functionalize the magnetic NPs for the control of the aggregation during deposition on the GO surface. Next, the use of polyethylenimine ( pei ), a widely employed coating agent in the pharmaceutical industry, is investigated to modulate the behavior of the composite in water …”

Exploring the potential of laser desorption ionisation time-of-flight mass spectrometry to analyse organic capping agents on inorganic nanoparticle surfaces

“…MALDI analysis of polymers showed that it was not possible to obtain intact ions of the polymer either. For instance, PEI with a molecular weight of ~ 8 kDa was not detected by its molecular ions but showed fragment ions in the range m/z 200–1000 [ 26 ]. A study of 20 kDa PVP revealed only fragment ions up to m/z 5000 [ 27 ], whereas in another study, a polydisperse 40 kDa PVP did not allow to obtain structural information such as the repeating unit or the end groups [ 28 ].…”

A silica-based magnetic platform decorated with mixed ligand gold nanoparticles: a recyclable catalyst for esterification reactions

“…Starting from a core@shell structure composed of superparamagnetic g-Fe 2 O 3 (maghemite) nanoparticles coated with SiO 2 and taking advantage of the chemical versatility of the silica materials, [8][9][10] we surface-functionalized them with amine to anchor the catalytically active AuNPs. We present the synthesis of these Fe 2 O 3 @SiO 2 @Au hierarchical nanospheres and verify that the AuNPs bonded to the silica retain their catalytic activity.…”