Portable Biosensor Based on Magnetic Nanoparticles

Title: A portable handheld AC magnetic susceptometer for detection of biomolecules tagged to magnetic nanoparticles (Completed)


Advisor: Prof. Sameer Sonkusale (ECE.,Tufts), Prof. Eddie Goldberg (Molecular Biology., Tufts), Late Prof. Robert Guertin (Physics, Tufts)


Researchers: Kyoungchul Park



Magnetic nanoparticles have recently received increased interest as a feasible basis for the development of rapid and compact biological sensors. Measurement of the AC magnetic susceptibility of nanomagnets is known to yield information about the hydrodynamic behavior of the magnet and has been shown to be an effective way to detect the binding of proteins to nanomagnets.

The time-dependent magnetic properties of aqueous media containing magnetic particles are altered when biomolecules such as proteins bind to the nanoscale particles in suspension. The cause of the change in magnetic relaxation times is the larger hydrodynamic radius of the biomolecule-magnetic particle composite compared with the magnetic particle alone. Theory shows that the relaxation time is proportional to the hydrodynamic volume of the particle in suspension. Time-sensitive magnetic measurement devices such as AC magnetic susceptometers with very small magnetic fields are able to measure a spectrum of relaxation times within a suspension of magnetic particles thus enabling particle sizes to be measured.

Our final goal is to develop a single chip solution of AC magnetic susceptometer for the rapid identification of cellular, viral, and molecular targets in clinical and environmental samples.


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