Engineering Magnetically Activated Liposome-based Drug Delivery Systems

Localized drug delivery systems have shown promise, with a wide variety of approaches to creating an effective solution. We aim to combine synthetic biology and magnetics to create a novel liposomal drug delivery system. Robust liposomes were created using 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) lipids, cholesterol, and a small percentage of biotinylated lipids. Streptavidin coated magnetic beads were incorporated into the outer leaflet of the liposomes through a biotin-streptavidin bond. The liposomes were loaded with a fluorescent calcein dye as a method of visualizing the liposomes and to monitor leakage. Microfluidic channels were fabricated to retain the liposomes and magnetic forces were concentrated on the liposomes, in the microfluidic channel. We then placed the device under Helmholtz coils to generate a magnetic force to rupture the liposomes while performing live fluorescence microscopy imaging. The current in the Helmholtz coils was slowly increased until a sufficient magnetic force was achieved near the magnetic features to rupture the liposomes, allowing the contents to be released to the surrounding environment. We have analyzed the impact of varying magnetic designs on the magnetic force applied to the liposome constructs. Our work would be beneficial in many areas, including controlled drug delivery for intestinal disorders, such as the class of irritable bowel diseases. This approach will be useful in the future in a wide diversity of fields including drug delivery, biomaterials, and disease classes.