ABSTRACT
Magnetic manipulation is a technique that has been used since the middle of the nineteenth century, though in a nonbiological context. At that time, large magnets were used to separate metals from dirt in the mining industry. However, it was not until the invention of what is known as high-gradient magnetic separation (HGMS), usually attributed to J.H.P. Watson (Watson, 1973) that the method has found applications in medicine, chemistry, and biotechnology. The technique allows the trapping of even weakly magnetized particles by producing very strong and very local magnetic šeld gradients.
