Preliminary 3-D analysis of a high gradient magnetic separator for biomedical applications

A prototype portable high-gradient magnetic separator is being developed for in vivo magnetic separation from human blood flow. In this separator design, an array of biocompatible capillary tubing and magnetizable wires is immersed in an external magnetic field, which is generated by two parallel permanent magnets. The wires are magnetized and the high magnetic field gradient from the magnetized wires helps to collect blood-borne magnetic nanospheres. In this study, a 3-D mathematical model was created and the effect of tubing–wire configurations on the capture efficiency (CE) of the system was analyzed using COMSOL Multiphysics 3.3®. The results show that an optimal design was a configuration characterized by bi-directionally alternating wires and tubes as an optimal design. In vitro experiments verified the theoretical predictions for the CE. The CE of the optimal design was more than 20% higher than that of the other design at 20 cm/s. The results further optimized a prototype portable magnetic separator suitable for rapid sequestration of magnetic nanospheres from the human blood stream while accommodating necessary clinical boundary conditions.