| A drug delivery system based on dual responsive units was developed. An appealing pH- and
thermo-responsive triblock terpolymer as the drug carrier was synthesized by RAFT polymerization of
N-isopropyl acrylamide and methacrylic acid monomers using PEG-RAFT agent. The Fe3O4 magnetic
nanoparticles were synthesized by co-precipitation of Fe salts. Synthesized samples were characterized
by FT-IR, XRD, GPC, SEM and TEM. The dual responsive behaviour and self-assembly of the triblock terpolymers
in aqueous solution were investigated using UV–vis transmittance and DLS. Based on the results of
DLS and TEM, the average size of micelles was 170, 125 and 30 nm. The triblock terpolymer was used as a
chemotherapy drug carrier and doxorubicin as a model drug. The release rate of the drug at two different
temperatures (37 C and 42 C) and pHs (5.8 and 7.4) was studied. The in vitro cytotoxicity assay of free
doxorubicin and drug-loaded magnetic nanoparticles was studied. The MTT assay exhibited that these
polymers are biocompatible and no toxicity. As well, IC50 of the DOX-loaded triblock terpolymer in MTT
test demonstrated that these systems could be suitable for the treatment of cancer. |