(195e) Magnetic Particle Tracking Velocimetry as a Tool for Optimizing Magnetic Isolation of Pancreatic Islets

Magnetic isolation is a promising method for separating and concentrating pancreatic islets for transplantation in Type 1 Diabetes patients. We are developing a continuous magnetic islet sorter to overcome the restrictions of current purification methods that result in limited yield, viability and purity of the isolated islets. Islets are magnetized by infusing superparamagnetic microbeads into islets' vasculature via arteries that serve the pancreas. The performance of the islet sorter depends on the resulting speed of the islets in an applied magnetic field, a property known as magnetophoretic mobility. Essential to the design and operation of the magnetic sorter is a method to measure the magnetophoretic mobilities of magnetically infused islets. We have developed a magnetic particle tracking velocimeter (MPTV) to measure the magnetophoretic mobility of particles up to 1000 microns in diameter. Velocity measurements are performed in a well-characterized uniform magnetic energy gradient using video imaging followed by analysis of the video images using a computer algorithm that produces an absolute histogram of mobilities. High-density Ficoll® solutions were used to suspend magnetically-labeled islets and surrogate particles, such as 200 to 350 micron alginate beads. Mobility distributions obtained indicated that magnetized islets have sufficient mobility to be captured by the proposed sorting method, with this result confirmed in test isolations of magnetized islets.