A model for predicting magnetic particle capture in a microfluidic bioseparator

Abstract

A model is presented for predicting the capture of magnetic micro/nano-particles in a bioseparation microsystem. This bioseparator consists of an array of conductive elements embedded beneath a rectangular microfluidic channel. The magnetic particles are introduced into the microchannel in solution, and are attracted and held by the magnetic force produced by the energized elements. Analytical expressions are obtained for the dominant magnetic and fluidic forces on the particles as they move through the microchannel. These expressions are included in the equations of motion, which are solved numerically to predict particle trajectories and capture time. This model is well-suited for parametric analysis of particle capture taking into account variations in particle size, material properties, applied current, microchannel dimensions, fluid properties, and flow velocity.

Effects of particle–fluid coupling on particle transport and capture in a magnetophoretic microsystem

“…These can be integrated using a number of different numerical techniques. We have used a fourth-order RungeKutta method for our analysis (Furlani 2006;Furlani et al 2007).…”

“…Magnetic functionality can be integrated into these systems by embedding magnetic field source elements in the substrate, in proximity to the flow channels. These elements can be magnetically passive structures such as nickel-based microbars, or active voltage-driven conductors (Choi et al 2000(Choi et al , 2001Furlani 2001;Smistrup et al 2005Furlani 2006Furlani and Sahoo 2006;Furlani et al 2007;Smistrup et al 2008). In the former case, an external field source is used to magnetize the elements.…”

“…His results show that blood cells can be efficiently separated by embedded magnetic element array. Furlani has also developed transport models to study various biomedical applications including magnetic-assisted gene transfection (magnetofection) (Furlani and Ng 2008) and magnetic targeting of therapeutic drugs in the human vascular system (Furlani and Ng 2006;Furlani and Furlani 2007). Nandy et al (2008) analytically computed capture efficiency as a function of the strength of a field-induced magnetic dipole and the particle size.…”

Microdevice for continuous flow magnetic separation for bioengineering applications

“…neodymium magnet) or soft microstructures (e.g. nickel-based) elements have been employed for realizing magnetophoresis [16][17][18][19][20][21][22][23][24][25]. Soft magnetic materials are realized on the bottom or wall of microfluidic devices using standard microfabrication processes.…”

Magnetic micro/nanoparticle flocculation-based signal amplification for biosensing

“…7,8 The forces that affect the motion of the magnetic particles in a microfluidic system are magnetic force, drag force, gravity force, Brownian force, and lift force and have been reviewed in various articles. 2,[9][10][11] Magnetic separation allows removing only target molecules from complex biological mixtures and preparing "clean" solutions that can be used with delicate micro/nano devices. This feature makes magnetic particles attractive tools to cooperate with other micro/nano devices, such as microcantilevers, 12 nanowires, 13 and microfluidic-based biochips.…”