Macromolecular engineering and stimulus response in the design of advanced drug delivery systems

Extensive research activity is currently devoted to controlled drug delivery systems, mainly as nano-sized particles. Although biocompatible and (bio)degradable polymers play a key role in this field, their shaping into colloidal particles (e.g., polymeric micelles and nanoparticles) usually requires the proper design of amphiphilic copolymers as effective stabilizers. Strategies for synthesizing these copolymers that preserve the intrinsic properties of the constitutive polymers are discussed in this article. Synthesis of amphiphilic copolymers with a more complex structure and endowed with functionality is also considered, with the purpose of enhancing the performance of the nanocarriers. The focus is increasingly on nanocarriers of the third generation, which resist coalescence and elimination by the immune system, and which are readily incorporated into chosen target cells. The more recent quest is for smart nanocarriers that exhibit the additional capacity of being stimuli-responsive.