ph-responsive nanosystems based on reduced graphene oxide grafted with polycaprolactone-block-poly(succinyloxyethylmethacrylate) for doxorubicin release

Ph-responsive nanocarriers were synthesized via polycaprolactone-b-poly(succinyloxyethylmethacrylate) copolymers grafted onto reduced graphene oxide (rgo-g-pcl-b-psema) for anticancer drug delivery applications. for this propose, ε-caprolactone monomer was polymerized from –oh groups of rgo with ring-opening polymerization (rop) to obtain polycaprolactone grafts (rgo-g-pcl). in the next step, 2-hydroxyethylmethacrylate monomer was polymerized from pcl end through atom transfer radical polymerization to afford rgo-g-pcl-b-poly(hydroxyethylmethacrylate) (phema). the ph-responsive rgo-g-pcl-b-psema was obtained by reacting rgo-g-pcl-b-phema with excess succinic anhydride in pyridine under mild conditions. the ph sensitivity of nanosystems was confirmed via dynamic light scattering at ph values of 4 and 7.4. doxorubicin encapsulation efficacy was calculated to be 92%. the effect of ph on release behaviors of rgo-g-pcl-b-psema nanocarriers was investigated. the release rates at ph values of 7.4, 5.4 and 4 were about 52.1, 64.2 and 68.63 wt% after 775 min and at 37 °c. the release rate was improved at tumor simulated environment (42 °c and ph ≤ 5.4). the cytotoxic effects of nanosystems were appraised by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (mtt) assay, and the results indicated that novel smart nanosystems were nontoxic to mcf-7 cells and can be applied as anticancer drug delivery systems.