Dual Nano-Carriers using Polylactide-block-Poly(N-isopropylacrylamide-random-acrylic acid) Polymerized from Reduced Graphene Oxide Surface for Doxorubicin Delivery Applications

The stimuli-responsive nanocomposites were designed as drug delivery nanocarriers. Thanks to promising properties such as large surface area and easy chemical functionalization, the graphene derivatives can be used for the drug delivery applications. For this purpose, in the current work, the poly(L,D-lactide)-block-poly(N-isopropylacrylamide-rand-acrylic acid) grafted from reduced graphene oxide (rGO-graft-PDLA-block-P(NIPAAm-rand-AAc)) was synthesized by the ring opening polymerization (ROP) and atom transfer radical polymerization (ATRP). As compared with the traditional radical polymerizations, living polymerizations are among the most-utilized methods to achieve surface initiated polymer brushes as they provide excellent control over the polymers composition. The average sizes of rGO-graft-PDLA-block-P(NIPAAm-rand-AAc) nanocomposite using the dynamic light scattering (DLS) measurements at pH values of 4.0 and 7.4 were 240 and 150 nm, respectively. The lower critical solution temperature (LCST) of rGO-graft-PDLA-block-P(NIPAAm-rand-AAc) was determined to be 39 °C through the ultraviolet-visible (UV-Vis) spectroscopy. The doxorubicin hydrochloride (DOX)-loading capacity was 99 %. The release of DOX increased at 42 °C compared to 37 °C. The results confirmed that the pH- and temperature-dependent releasing of this drug nano-carrier was beneficial for the anticancer at the tumor-like environment. The biocompatibility was also confirmed by assessing the survival rate of breast cancer cell line (MCF7) using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The synthesized nanoparticles would have an excellent potential in the anticancer drug delivery.