Preparation and characterization of OH‐functionalized magnetic nanogels under UV irradiation

Abstract

ABSTRACT:A novel preparation method of net magnetic polymer nanogels with swollen shell was developed. UVinduced photopolymerization of 2-hydroxyethyl methacrylate (HEMA) was performed in the magnetite aqueous suspension, free of any additive to obtain monodisperse magnetic nanogels with swollen shell. Owing to the step-growth polymerization of the monomer, the particle size of magnetic nanogels can be conveniently manipulated by changing the irradiation time and the volume of the monomer dropped. The crystalline structure of Fe 3 O 4 core and chemical composition of PHEMA magnetic nanogels were characterized by using X-ray diffraction, Fourier transform infrared spectroscopy, and thermogravimetric analysis, respectively. Particle sizes, size distributions of magnetic nanogels in swollen state and dry state were measured by photo-correlation spectroscopy (PCS) and transmission electron microscopy (TEM), respectively. The morphology of swollen magnetic nanogels and that of polymer capsules obtained from magnetic nanogels etched by hydrochloride acid were observed by TEM. The high magnetizations and superparamagnetic behaviors of naked Fe 3 O 4 and magnetic nanogels at room temperature were confirmed by the measurement of hysteresis curves.

Poly(ethylene glycol)‐Coated Magnetite Nanoparticles: Preparation and Characterization

“…[3][4][5][6][7][8][9][10][11][12] The concentration of Fe 2þ /Fe 3þ was 1:2 and the synthesis was carried out under inert atmosphere to prevent Fe 2þ oxidation to Fe 3þ . DLS measurements showed an average size of Fe 3 O 4 particles of about 400 nm.…”

“…[11] These methods present some inconveniences such as the use of high temperature, the complexity of implementation, the difficulty to obtain narrow size distributions and the fact that generally the magnetic nanoparticles obtained are hydrophobic. We decided to use a reduction coprecipitation method [3][4][5][6][7][8][9][10][11][12] in order to obtain magnetite nanoparticles dispersed in water.…”

“…[12] The coating also often facilitates the stabilization of the nanoparticles in an environment with a slightly alkaline pH or a significant salt concentration. [1] In addition, coating plays an essential role in retarding clearance by the reticuloendothelial system (RES).…”

“…[2,21] In this article, we report a new fast and convenient method for preparing magnetic nanoparticles with a Fe 3 O 4 core and a poly(ethylene glycol) diacrylate (PEGDA) shell in water. We used a reduction coprecipitation method to obtain Fe 3 O 4 in aqueous solution [3,12] whereas the PEGDA coating was obtain via photochemical reaction at room temperature in an initiator free aqueous system. The fact that this method is solvent free and initiator free makes it ideal for biomedical applications.…”

Conjugation of enzyme on superparamagnetic nanogels covered with carboxyl groups

“…Theoretically, it was possible to prepare core-shell magnetic nanogels via photochemical method using quantum-sized Fe 3 O 4 nanoparticles as photoinitiator. Actually, magnetic nanogels with amino groups or hydroxyl groups had been successfully prepared by photochemical in situ polymerization in our group and the possible mechanism was proposed [20,21]. The surface of the synthesized magnetic nanogels remained reactive and could be available for post synthesis chemical modification.…”