Tumor Microenvironment and Intracellular Signal-Activated Nanocomposites for Anticancer Drug Delivery

The use of nanomaterials for drug delivery and cancer therapy has well established itself over the past decades. Compared with free chemotherapeutics, nanoparticle drug delivery systems achieve better performance in various areas, such as enhanced bioavailability, extended blood circulation time, and systemic control of drug release. Furthermore, coupling stimuli-activated functionality with these nanocomposites provides them with superior advantages in bypassing biological obstacles, maximizing the therapeutic efficacy, and minimizing the side effects of loaded drugs. Because of the active metabolism of tumor cells, the tumor microenvironment exhibits several distinguishing properties (e.g., acidic pH, over-expressed enzyme, hypoxia, and reductive environment) compared with normal tissues or cells, which has been a key rationale for the development of stimuli-activated nanomaterials for cancer therapy. In this chapter, we summarized the recent advances in various tumor microenvironment and intracellular signal-activated nanocomposites for anticancer drug delivery. Future perspectives on design consideration were also discussed in detail.