Chapter Twenty Five - Neutrophil-based drug delivery systems

Neutrophils are the most abundant white cells in the blood circulation, and they are classically considered the first line of defense against intruders in the human body. Recent evidence has demonstrated that the neutrophils are key actor in several human diseases, including cancer. Neutrophils play crucial and multiroles in cancer development and progression. In particular, depending on the stimuli of the surrounding environment, they can polarize to different phenotypes, by exerting opposite functions. Neutrophils can have both anti-tumor properties as well as tumor-supportive and immune-suppressive properties. Taking advantage of their physiological properties like crossing biological barriers, they can be used as an innovative advanced drug delivery system for improving drug targeting and also therapeutic efficacy. In this book chapter, we discuss the most recent advances in engineering neutrophils as drug and targeting delivery systems. We provide recent examples from our own research work on neutrophil-based delivery systems as well as from others. With this chapter, we aim at providing a broad understanding of the potential of such neutrophil systems for cancer therapy and other biomedical applications.