Circulatory Cells as Tumortropic Carrier for Targetability Improvement

Background How to achieve high targeting efficiency for drug delivery system is still one of the most important issues that tumor diagnosis and non-surgical therapies faced. Although nanoparticle-based drug delivery system made an amount of progress in extending circulation time, improving targetability, controlled drug release etc., yet the targeting efficiency remained low, and the development was limited to reduce side effects with overall survival rates unchanged or improved a little. Objective This paper aims to review current researches on the cell-driven drug delivery systems, and discuss the potential obstacles and directions for cell-based cancer therapies and diagnosis. Methods More than one hundred references were collected, and this paper focused on red blood cells, monocytes, macrophages, neutrophils, natural killer cells, T lymphocytes, mesenchymal stem cells, cell membrane, artificial cells and extracellular vesicles, then summarized 1) the utilizable properties, 2) balancing cargo-loading amounts and cell function, 3) cascade strategies for targetability improvement. Main findings circulatory cells and their derivatives were featured by good biocompatibility, long circulation time in blood, unique chemo-migration and penetration ability. On the base of backpack and encapsulation approach, cargo loading amounts and cell function could be balanced through regulating membrane receptors, particle material/size/shape/structure and incubation temperature, etc. The cell-driven drug delivery system met most of the demands that nanoparticle-based delivery system failed to for effective tumortropic delivery. Conclusion Despite of new challenges, cell-driven drug delivery system generally brought great benefits to and shed a light on for cancer therapy and diagnosis.