Micro- and nano-magnetic particles for applications in biosensing

This article reviews the development of electrochemical biosensors, incorporating magnetic particles, for detecting biomolecules (nucleic acids and proteins) and cells. Magnetic particles (MPs) of micro- and nanoscale, mimicking the size of molecules in nature, possess interesting characteristics that facilitate the purification and detection of biomolecules in a wide range of samples. In particular, the high surface area and the paramagnetic or superparamagnetic properties of these tiny particles provide an attractive technology platform for the design of electrochemical biosensors. Examples of electrochemistry-based approaches to achieve the separation and detection of bioentities utilizing MPs are described. Emphasis is placed on the strategies to incorporate the electrochemical labels to the MPs and the methods to achieve the dual function of electrochemical detection and magnetic separation. The protocols to make MPs as labels in biological sensors are also discussed.