Scheme 1. (a) Conjugation of PTX and CDDP with PMAn. (b) Schematic Representation of Self-Assembly of PMA–PTX–CDDP Conjugate into Spherical Nanoparticles. (c) Schematic Representation of Cellular Internalization of PMA–PTX–CDDP-NPs into Cancer Cells Lead to the Reduction of 3D-Tumor Spheroids.