Magnetic nano-particles and their applications in immunoassays

Biocompatible magnetic nano-particles show great potential in bio-magnetic applications, such as MRI contrast agents, drug delivery, magnetically labeled immunoassays, and so on. In this work, the feasibility of magnetically labeled immunoassay using bio-compatible magnetic nano-particles is investigated. To do this, we study the synthesis technologies for magnetic nano-particles of Fe ₃O₄, as well as the coating of various bio-probes onto the magnetic nano-particles to detect the bio-targets avidin, such as, etc. Furthermore, different measurements, like magnetic relaxation and saturated magnetization, for the amounts of bio-targets are developed. In order to achieve an ultra-high sensitivity in magnetically labeled immunoassays, we used SQUIDs because SQUIDs are the most sensitive sensors for magnetic signals. The characterizations of these magnetically labeled immunological measurements are discussed.