Fig. 2
a UV–Vis spectra of PEI.NH2-(PEG-CTX)-mPEG, PEI.NH2-DTPA-(PEG-CTX)-mPEG, and mPEI-CTX/DOX dispersed in water at a polymer concentration of 200 μg/mL. b Cumulative release of DOX from mPEI-CTX/DOX in PBS buffer (pH = 7.4) and acetate buffer (pH = 5.0) at 37 °C. c and d CCK-8 assay of C6 cells treated with mPEI-CTX/DOX, mPEI/DOX, and free DOX at different DOX concentrations for 24 and 48 h