Numerical investigation of flow-through immunoassay in a microchannel

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American Institute of Physics


Immunomagnetic separation (IMS) is a method to isolate biomaterials from a host fluid in which specifically selected antibodies attached to magnetic particles bind with their corresponding antigens on the surface of the target biological entities. A magnet separates these entities from the fluid through magnetophoresis. The method has promising applications in microscale biosensors. We develop a comprehensive model to characterize the interaction between target species and magnetic particles in microfluidic channels. The mechanics of the separation of target nonmagnetic N particles by magnetic M particles are investigated using a particle dynamics simulation. We consider both interparticle magnetic interactions and the binding of the functionalizing strands of complementary particles. The temporal growth of a particle aggregate and the relative concentrations of M and N particles are investigated under different operating conditions. A particle aggregate first grows and then exhibits periodic washaway about a quasisteady mean size. The washaway frequency and amplitude depend on the initial fractional concentration of N particles while the aggregate size scales linearly with the dipole strength and inversely with the fluid flow rate.



Ion-mobility spectrometry, Microfluidics, Biophysical techniques, Collision theories, Magnetic fields


Sinha, A., Ganguly, R., Puri, I. K. (2010). Numerical investigation of flow-through immunoassay in a microchannel. Journal of Applied Physics, 107(3). doi: 10.1063/1.3284077