In situ synthesis of magnetic poly(N-tert-butyl acrylamide-co-acrylic acid)/Fe₃O₄ nanogels for magnetic resonance imaging

Abstract

Poly(N-tert-butylacrylamide-co-acrylic acid)/Fe 3 O 4 (P(TBA-co-AA)/Fe 3 O 4 ) nanogels have been synthesized successfully by two steps: firstly, poly(N-tert-butylacrylamide-co-acrylic acid) (P(TBA-co-AA)) nanogels were synthesized through emulsion precipitation polymerization by using N-tertbutylacrylamide (TBA) and acrylic acid (AA) as reactive monomers; then P(TBA-co-AA)/Fe 3 O 4 nanogels were synthesized by in situ oxidation of Fe 2+ into Fe 3 O 4 nanoparticles inside the networks of the P(TBA-co-AA) nanogels. The prepared P(TBA-co-AA)/Fe 3 O 4 nanogels were about 70 nm in dry state, and 118.9 nm in aqueous solution with a low polydispersity index (PDI) of 0.124. The small size and low PDI of the magnetic nanogels could be applied in living body. Besides, the nanogels had good superparamagnetic property, and high r 2 relaxivity value of about 512.01 mM À1 s À1 . These magnetic properties endowed the nanogels with a new ability to be applied in T 2 -style imaging. In short, this work would provide the possibility of using the P(TBA-co-AA)/Fe 3 O 4 nanogels as contrast agents for high resolution of magnetic resonance imaging (MRI).

Revealing the NIR-triggered chemotherapy therapeutic window of magnetic and thermoresponsive nanogels

“…First, the maximum tolerated dose of the MNGs was studied in healthy NMRI nude mice to evaluate sufficient doses and short-term toxicity. Five doses with increasing amounts of MNG (10,20,40,70, and 100 mg kg −1 ) were injected intravenously through the tail vein and the mice were observed for 15 days. Since there were no signs of compound-related toxicity, five extra injections of 100 mg kg −1 were performed for five consecutive days to reach a total accumulated dose of 500 mg kg −1 .…”

“…These range from a simple mixture of MNPs and nanogel suspensions 20,32,37 to the in situ synthesis of nanogels in the presence of a solution of MNPs, 35,38,39 or vice versa by the in situ synthesis of MNPs in a nanogel dispersion. 40,41 However, the non-covalent incorporation methods have important drawbacks like the desorption of the MNPs or the aggregation of the particles inside the nanogels that affects both the magnetic properties of the composites and the drug loading capacity of the systems.…”

Synthesis and self‐assembly of multiple‐responsive magnetic nanogels

“…In this study, compared with our group's previous work, monodisperse IPN NGs composed of poly(N‐isopropylacrylamide) (PNIPAM) and poly (methacrylic acid) (PMAA) interpenetrating networks were prepared by emulsion precipitation polymerization method, and then Fe 3 O 4 NPs were incorporated into IPN matrix by in‐situ oxidation‐reduction precipitation method. The as‐prepared monodisperse magnetic NGs were sensitive to temperature, pH, and magnetic field, respectively.…”