Redox-responsive degradable microgel modified with superparamagnetic nanoparticles exhibiting controlled, hyperthermia-enhanced drug release

Abstract

A novel degradable microgel based on poly(N-isopropylacrylamide) (pNIPA) cross-linked with N,N’-bisacryloylcystine (BISS) and containing superparamagnetic iron oxide nanoparticles (SPION@CA) was synthesized by semi-batch precipitation polymerization and examined as a potential hyperthermia-enhanced drug carrier. The pNIPA provided the microgel with temperature sensitivity, the BISS was responsible for degradation in the presence of glutathione (GSH) (an –S–S–bond reductor naturally present in cells), while the SPION@CA permitted remote control of temperature to improve drug release. The microgels exhibited volume phase transition temperature at ca. 34 °C, which is near the human body temperature, and were stable across a wide range of temperatures and ionic strengths, as well as in the blood plasma at 37 °C. It was found that the presence of SPION@CA in the polymer network of the microgels enabled the temperature to be increased up to 42 °C by an alternating magnetic field, and that increasing the temperature from 37 to 42 °C significantly enhanced the releasing of the anticancer drug doxorubicin (DOX). The highest DOX release (82%) was observed at pH 5, 42 °C, and in the presence of GSH, and the lowest (20%) at pH 7.4, 37 °C, and in the absence of GSH. MTT assay indicated that compared to free doxorubicin, the microgel particles loaded with doxorubicin have comparable cytotoxicity against MCF-7 cancer cells while being significantly less toxic to MCF-10A healthy cells. Graphical abstract

Upcycling of Acid-Leaching Solutions from Li-Ion Battery Waste Treatment through the Facile Synthesis of Magnetorheological Fluid

“…The M s values for samples 1 and 3 are 84.4 and 65.6 emu g −1 , respectively. The values of the saturation magnetization and the shape of the hysteresis for sample 1 are similar to the characteristics of the bare iron oxide nanoparticles, where M s is about ~90 emu g −1 [ 38 , 39 , 40 , 41 ]. According to the values for the nanoparticles obtained from the hydrometallurgical waste, Sankaran et al present ferromagnetic Co 0.87 Ni 0.13 Fe 2 O 4 and CoFe 2 O 4 nanoparticles with M s of about 62 emu g −1 and a coercivity of about 1420 and 760 Oe, respectively [ 32 ].…”

1H-NMR studies on the volume phase transition of DNA-modified pNipmam microgels

“…For drug delivery systems this is important since the VPT should be used to trigger the release of the drugs. 3,23,[38][39][40] mG-DNA hybrid structures could for example be useful for siRNA delivery 9,41 as well as for biosensing, as it is described for glucose. 42 A VPTT around the body temperature combined with the high specific surface of mG and with that a high loading capacity makes them promising candidates for these and even more biomedical applications.…”

Crafting Iron Oxides for Next-Generation Biomedical Applications

“…The release becomes faster, up to 82% under hyperthermia conditions existing in certain cancer cells (pH 5.0, with a GSH concentration of 40 mM). 125 In this condition, the degradation of the polymer matrix can be achieved by combinational means, such as redox GSH, pH, and thermal degradation. This higher degradation leads to a more rapid release of the drug within the carrier.…”