Biological Cells as Therapeutic Delivery Vehicles

Cells have innate targeting mechanisms that can improve drug-delivery efficacy and decrease off-target effects. Multiple cell types, such as red blood cells (RBCs), platelets, neutrophils, mesenchymal stem cells (MSCs), and bacteria can be used as delivery vehicles. Cells can be engineered to have desired surface markers for improved tissue and cell targeting. Synthetic biology can be used to engineer cells to implement desired therapeutic outcomes when native cells do not exhibit the required phenotype. One of the significant challenges remaining in the field of drug delivery is insufficient targeting of diseased tissues or cells. While efforts to perform targeted drug delivery by engineered nanoparticles have shown some success, there are underlying targeting, toxicity, and immunogenicity challenges. By contrast, live cells usually have innate targeting mechanisms, and can be used as drug-delivery vehicles to increase the efficiency with which a drug accumulates to act on the intended tissue. In some cases, when no native cell types exhibit the desired therapeutic phenotype, preferred outcomes can be achieved by genetically modifying and reprogramming cells with gene circuits. This review highlights recent advances in the use of cells to deliver therapeutics. Specifically, we discuss how red blood cells (RBCs), platelets, neutrophils, mesenchymal stem cells (MSCs), and bacteria have been utilized to advance drug delivery. One of the significant challenges remaining in the field of drug delivery is insufficient targeting of diseased tissues or cells. While efforts to perform targeted drug delivery by engineered nanoparticles have shown some success, there are underlying targeting, toxicity, and immunogenicity challenges. By contrast, live cells usually have innate targeting mechanisms, and can be used as drug-delivery vehicles to increase the efficiency with which a drug accumulates to act on the intended tissue. In some cases, when no native cell types exhibit the desired therapeutic phenotype, preferred outcomes can be achieved by genetically modifying and reprogramming cells with gene circuits. This review highlights recent advances in the use of cells to deliver therapeutics. Specifically, we discuss how red blood cells (RBCs), platelets, neutrophils, mesenchymal stem cells (MSCs), and bacteria have been utilized to advance drug delivery. a disease that causes enlarged blood vessels and uncoordinated movements. the synthesis of materials, synthetic systems, or machines that are inspired by nature. a water-soluble vitamin that can be used to for labeling target molecules. a disease that affects the lungs and limits the ability to breathe over time. an aggressive type of cancer that occurs in the brain and/or spinal cord. a bleeding disorder from missing the clotting factor VIII protein. a process to prevent and stop bleeding. cells derived from adult cells and reprogrammed to become pluripotent stem cells, which are stem cells that have the ability to self-renew and to give rise to all of the cells of the tissues in the body. directional movement of a cell in response to a magnetic field. a cancer that forms in the bone marrow. a microscopic particle that is commonly used to transport small molecules for therapeutic applications. a biologically inactive compound that can be metabolized in the body to produce an active drug. a multipotent cell that is programmed to become a specific type of adult cell. T cells that have a reduced capacity to secrete cytokines and an increased expression of inhibitory receptors. abnormally low platelet counts in the blood.