Leukocyte-based delivery systems for enhanced nanotheranostics of inflammation and cancer.

As a part of the immune system, leukocytes (LEs) have the features of circumvention of immunogenicity as well as recruitment to sites of inflammation during infection and tumorigenesis. Utilizing LEs as vehicles to carry theranostic agents is a promising strategy for highly efficient targeted delivery and treatment for inflammation and cancer. Specifically, the LEs, similar to 'Trojan horses', can bypass the immune system and thus enhance the therapeutic effects on inflammation and cancer. In this context, the latest progress of LEs-based delivery systems for improving theranostics of inflammations and cancers is summarized, includingincubation andinternalization strategy. Although the therapeutic efficacy of LEs-based delivery systems has been achieved, the system construction is complex and the effect is not fulfilling demand completely. Encouragingly, a most recent work reported that the supramolecular arrangement of proteins on the nanocarriers would drive them to be selectively uptaken by neutrophils, opening a new avenue for diagnosis and treatment of inflammation. Moreover, enucleated cells are considered as the biomimetic drug delivery vehicle to retain the organelles for a range of diseases in a safe, controllable and effective manner. These novel findings provide more opportunities for researchers to rethink and redesign the LEs-based delivery systems to overcome existing limitations and broaden their usage, especially in clinical medicine.