Incorporation of iron oxide nanoparticles into temperature-responsive poly (N-isopropylacrylamide-co-acrylic acid) P (NIPAAm-AA) polymer hydrogel

Abstract

Magnetic polymer particles have attracted much attention because of their ubiquitous use in biomedical field such as biomolecule separation, drug carriers, imaging and etc. Iron oxide magnetic nanoparticles were incorporated into temperature responsive poly (N-isopropylacrylamide) (PNIPAAm) polymer hydrogel by a seed polymerization following a surface modification step. Iron oxide magnetic nanoparticles (50-100 nm) prepared by co-precipitation method were modified with silica (SiO 2 ) and 3-(trimethoxysilyl) propyl methacrylate (MPS) to introduce polymerizable vinyl group (−CH=CH 2 ) at the surface of the nanoparticles. Then, the Fe 3 O 4 /SiO 2 /MPS particles were used as seed in polymerization of N-isopropylacrylamide (NIPAAm) and acrylic acid (AA). Here N, N'-methylenebisacrylamide (MBA) and potassium persulphate (KPS) were used as a cross-linker and initiator respectively. Dynamic Light scattering (DLS) results indicated a decrease of hydrodynamic diameter of magnetic Fe 3 O 4 /SiO 2 /MPS/poly (NIPAAm-AA) polymer particles with increasing temperature. Surface functionality and polymer coating, morphology, chemical composition and presence of iron oxide in the magnetic polymer particles were evaluated by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), thermogravimetric analysis (TGA) and X-ray diffraction (XRD) respectively. The content of magnetic part was more than 50 wt.% determined by TGA, satisfactory for separation of the final particles from a dispersed media by external magnet. Therefore, the magnetic polymer particles prepared here could be a potential candidate for separation technology.

Synthesis and Characterization of Thermoresponsive Hydrogels Based on N-Isopropylacrylamide Crosslinked with 4,4′-Dihydroxybiphenyl Diacrylate

“… 17 This temperature-modulated swelling property has been applied to develop an on–off switch for various activities such as drug delivery, controlled release, etc. 14 , 18 , 19 In addition, the LCST can be modified through incorporating a hydrophobic or hydrophilic comonomer/crosslinker to adjust the hydrophilic–hydrophobic balance within the polymer. Usually, biomedical applications require the LCST to be between ambient temperature and body temperature (∼37 °C) or even above body temperature.…”

Novel dual‐responsive semi‐interpenetrating polymer network hydrogels for controlled release of anticancer drugs

“…So, there is no comparison possible. However, loading and release of drugs for poly(NIPAA‐co‐AA) hydrogels have been studied a lot, but the results are different (Kim & Healy, ; Lue et al, ; Ma et al, ; Ma & Liu, ; Park et al, ; Pei et al, ; Prasannan et al, ; Rahman et al, ; Samah & Heard, ; Venegas‐Sanchez et al, ; Xia et al, ; Xiong et al, ; Xue et al, ; Zhang et al, ; Zhao et al, ). For an example, Samah and Heard synthesized poly(NIPAA‐co‐AA) nanogel with 5% (wt/vol) of AA using caffeine as a model permeant.…”

“…After incorporation of pH‐sensitive monomers like AA units, this continuous sequence of isopropylamide pendant groups and subsequently the continuous hydrophobic‐hydrophilic balance in PNIPAA chains are interrupted. As a result, the temperature sensitivity of copolymerized hydrogels would be expected to be much weaker (Park et al, ; Rahman, Nahar, Ullah, Elaissari, & Ahmad, ; Wei et al, ).…”

Epoxide functionalized γ‐Al2O3/Fe3O4/SiO2 nanocomposite and comparative adsorption behavior of a model reactive azo dye

“…Reference Fe 3 O 4 nanoparticles were prepared following standard procedure with slight modification . Co‐precipitation of Fe 2+ (2.855 g, 0.0102 mol) and Fe 3+ (3.127 g, 0.0190 mol) from their aqueous 25% NH 4 OH solution (pH ~ 10) was carried out in a three necked round flask under a nitrogen atmosphere for 2 hours at 85°C.…”