Temperature- and redox-responsive magnetic complex micelles for controlled drug release

An amphiphilic PCL-SS-PDMAEMA copolymer was synthesized by the combination of ring-opening polymerization (ROP) and atom transfer radical polymerization (ATRP) using a new disulfide functionalized double-head initiator with both terminal hydroxyl and bromine groups. Based on the self-assembly of the PCL-SS-PDMAEMA copolymer with oleic acid modified Fe3O4 nanoparticles in aqueous solutions, magnetic PCL-SS-PDMAEMA/Fe3O4 complex micelles with a saturation magnetization of 10.20 emu g(-1) were prepared. The investigation of magnetothermal properties of the magnetic complex micelles showed that the temperature of the magnetic micellar systems increased in the alternating magnetic field (AMF) and the increasing rate and steady-state temperature could be adjusted through altering the magnetic flux density. Benefitting from the thermal response of PDMAEMA and redox response of the disulfide bond, the magnetic complex micelles presented obvious temperature-and redox-responsive properties. The R-h of the magnetic complex micelles would decrease when the micellar solutions were heated. And when DTT was added into the magnetic micellar systems, the distributions of R-h broadened with the emergence of aggregates. Due to the magnetic, magnetothermal, temperature-and redox-responsive properties, the magnetic complex micelles were used as a carrier for drug delivery systems. Doxorubicin (DOX), an anticancer drug, was used as a model drug and loaded into the magnetic complex micelles. The magnetic complex micelles presented good properties for controlled release. The release rate and level could be controlled by adding an external AMF and altering the DTT concentration.