9 - Block copolymers for nanoscale drug and gene delivery

Abstract

Delivery systems play a vital role in disease treatment, especially cancer therapy. Typically, simple delivery systems and free drugs cannot tolerate the harsh condition of the biological systems. Therefore designing more sophisticated and smart platforms is a necessity for proper disease diagnosis and treatment. Amphiphilic block copolymers, which combine hydrophilic and hydrophobic segments at nanoscale, can interact with a variety of hydrophilic and hydrophobic drugs. Their microstructure depends on self-assembly at nanoscale, which itself depends on the chemical structure and surrounding environment. Block copolymers can form polymeric micelles in dilute solutions, which can serve as carriers for therapeutic and diagnostic agents. Moreover, such platforms can be engineered to enter the cell and deliver the payload to cytoplasm or cell nucleus. Block copolymer containing cationic residue can condense DNA or RNA via electrostatic interactions to carry them into the cells while preserving them from extracellular environment. Furthermore, such platforms can be tailored to respond to various endogenous/exogenous stimuli such as temperature and pH, which is highly desired for cancer therapy. In this section, various types of block copolymer for manufacturing nanostructured delivery systems will be discussed to pave a way for scientist to choose a best platform as a delivery agent.