Red Blood Cells as Drug Delivery and Imaging Agents: An Update

Abstract

Red blood cells are essential physiologic cellular components that are produced constantly at abundant levels throughout life, making them an easily obtainable vehicle for both targeted cellular delivery of exogenous drugs as well as non-invasive in vivo imaging of the vasculature. As red blood cells are readily acquired in sufficient quantities and minimally immunogenic by nature, red blood cell-based agents may allow delivery of pharmaceuticals into the body under conditions of both reduced toxicity and increased physiologic half-life, when compared to the non-carrier-based drug equivalent. Research efforts in this area have recently seen major advances that are likely to accelerate the translation of red blood cell-based carrier methods into the clinical setting in the near future. This includes the coupling of therapeutic agents to the external surface of red blood cells, as well as more refined methods for internal encapsulation of drugs within red blood cells or cell-based derivatives. Here we review some of the more recent advances in the field regarding the loading of various therapeutic agents onto red blood cells as well as the use of red blood cell based imaging agents for in vivo vascularity imaging.