Magnetic and Thermal-sensitive Poly(<em>N</em>-isopropylacrylamide)-based Microgels for Magnetically Triggered Controlled Release

Abstract

Magnetically and thermally sensitive poly(N-isopropylacrylamide) (PNIPAAm)/Fe3O4-NH2 microgels with the encapsulated anti-cancer drug curcumin (Cur) were designed and fabricated for magnetically triggered release. PNIPAAm-based magnetic microgels with a spherical structure were produced via a temperature-induced emulsion followed with physical-crosslinking by mixing PNIPAAm, polyethylenimine (PEI), and Fe3O4-NH2 magnetic nanoparticles. Because of their dispersity, the Fe3O4-NH2 nanoparticles were embedded inside the polymer matrix. The amine groups exposed on the Fe3O4-NH2 and PEI surface supported the spherical structure by physically crosslinking with the amide groups of the PNIPAAm. The hydrophobic anti-cancer drug curcumin can be dispersed in water after encapsulation into the microgels. The microgels were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), and UV-Vis spectral analysis. Furthermore, magnetically triggered release was studied under an external high frequency magnetic field (HFMF). A significant "burst release" of curcumin was observed after applying the HFMF to the microgels due to the magnetic inductive heating (hyperthermia) effect. This manuscript describes the magnetically triggered controlled release of Cur-PNIPAAm/Fe3O4-NH2 encapsulated curcumin, which can be potentially applied for tumor therapy.

Externally Addressable Smart Drug Delivery Vehicles: Current Technologies and Future Directions

“…Regardless of the method of heating, the actuator for thermally triggered delivery vehicles is typically a biomaterial that can retain its payload at physiological body temperature (∼37 °C) but rapidly deliver the drug upon localized heating (∼40−42 °C), as illustrated in Figure 2. 12 Among the most widely used actuator materials are those that can undergo some kind of phase transition between normal physiological temperature and a physiologically safe and accessible higher temperature, including polymers that exhibit a lower critical solution temperature (LCST) such as poly(N-isopropylacrylamide) (PNIPAM) 34 or poly(oligoethylene glycol methacrylate) (POEGMA), 35 hydrogels comprised of the same materials that exhibit a volume phase transition temperature (VPTT), 36 block copolymer micelles that conformationally reorient or invert upon heating, 37 or liposomes that undergo a phase transition and thus associated conformational variations in the lipid bilayer upon heating. 38 This latter category of thermally activated liposomes has in particular attracted interest given that the choice of phospholipid(s) used to assemble the liposome can result in the creation of either leaky membrane structures 38 or effective solubilization of the entire nanostructure 39 depending on the type of release kinetics desired.…”

Preparation and Application of Iron Oxide Nanoclusters

“…The biomedical applications of iron oxide nanoclusters have been focused on magnetically triggered drug release [48][49][50][51] and MRI contrast agents with high sensitivity [30,[52][53][54]. For magnetically triggered drug release, either iron oxide nanoparticles (>10 nm) and drugs were colocalized in nanocarriers [55] or porous iron oxide nanoclusters were created to increase drug loading by surface adsorption [16].…”

Magnetic Graphene-Based Nanosheets with Pluronic F127-Chitosan Biopolymers Encapsulated α-Mangosteen Drugs for Breast Cancer Cells Therapy

“…A wide variety of materials such as polymeric material [ 7 , 8 , 9 ], dendrimers [ 10 ], liposomes [ 5 , 11 , 12 , 13 , 14 ], magnetic nanoparticles [ 13 ], or graphene-based materials [ 15 , 16 , 17 ] have been proposed as a drug carrier to deliver anticancer drugs. Since it can be loaded with various anticancer drugs and can load both hydrophilic and hydrophobic pharmaceutical agents, graphene oxide (GO), a family of graphene-based material derivatives, is one of the potential novel drug delivery systems that is being developed widely.…”