Styrene coated iron nanobead for medical use

Medical magnetic beads encapsulated in polymer coating with bioactive molecules immobilized on the surface will be used as carriers for the most advanced medical techniques such as bio-screening and proteome analyses. Magnetic separation of the beads expedites the screening and analyses. The performances will be further improved by decreasing the sizes of the beads, thus increasing their specific surface area. However, for ferrite medical magnetic beads, which have been so far developed, decreasing their sizes down to nm region lowers magnetization, and thus making magnetic separation difficult. To solve this problem, Fe nanoparticles were prepared by a reverse micelle method, using FeSO/sub 4/ and NaBH/sub 4/ as starting material and a reducing reagent respectively. Magnetic beads of 150 nm size, in which iron nanoparticles of 10 nm diameter are encapsulated in a styrene polymer coating successfully fabricated. These styrene coated Fe (St-Fe) beads have magnetization about two times stronger, and a specific surface area about 300 times wider, than those reported for Dynabeads of 2.8 /spl mu/m diameter. Therefore, the fabricated beads are much more advantageous for magnetic separation and affinity couplings to capture targeted materials in bio-screening and analyses.