Magnetic separations for biological molecules (abstract)

Abstract

Magnetic separations in biological systems have been used as alternative to gravitational or centrifugal separations. There are several advantages to using magnetically separable particles as supports for biological molecules such as enzymes, antibodies, and other bioaffinity adsorbents. For example, when magnetic particles are used as solid-phase supports in immobilized enzyme systems, the enzyme can be selectively recovered from the media, including media containing suspended solids, allowing recycling in enzyme reactors. The practical development of magnetic separations has been hindered by several critical properties of the magnetic particles developed thus far. For example, large magnetic particles (e.g., having a mean diameter in solution greater then 10 μm) respond to weak magnetic fields and magnetic field gradients; however, they tend to settle rapidly, limiting their usefulness for reactions requiring homogeneous conditions. Superparamagnetic particles coated with polymers capable of binding bioaffinity adsorbents have been prepared. Their used in the separation of biological molecules from, or directed movement of the molecules in, the surrounding medium is discussed and separation times and efficiency is compared to conventional protein processing methods.