Theranostic nanostructures as nanomedicines

The development of therapeutics and imaging by nanostructure-based systems has posed an inspiring task for the current research in nanomedicine. This is due to the prerequisite of having innumerable nanocarriers and active agents for improved therapy, imaging, and controlled drug release in a single platform. The conventional diagnostic procedure and therapy (especially for cancer) are associated with many unfortunate consequences, such as severe side effects, high drug clearance rate, multiple drug resistance, unwanted drug distribution to other otherwise healthy tissues, and low concentration of drugs that finally reaches diseased cells. Consequently, it is necessary to develop novel approaches by employing novel nanocarriers to deliver the therapeutic and imaging agents specifically to the affected sites in a targetable manner and in sufficient amount within the therapeutic window. Theranostic nanomedicines are capable of achieving the systemic circulation, evading host defenses, and delivering the drugs and diagnostic agents at the targeted site to treat as well as to diagnose the disease at the cellular and molecular levels. Theranostic nanomedicines display several important merits over the conventional therapy due to high cellular drug uptake, high drug release, and minimum side effects. Various nanocarriers employed in nanotheranostics possess high drug accumulations in the targeted site of drug actions while minimizing the toxic effects on healthy tissues. This chapter focuses on the current research on nanostructure-based therapeutics and diagnostics systems, including benefits, costs, and future challenges.