On-chip magnetophoretic isolation of CD4 + T cells from blood

Abstract

This paper presents the design, fabrication, and testing of a magnetophoretic bioseparation chip for the rapid isolation and concentration of CD4 þ T cells from the peripheral blood. In a departure from conventional magnetic separation techniques, this microfluidic-based bioseperation device has several unique features, including locally engineered magnetic field gradients and a continuous flow with a buffer switching scheme to improve the performance of the separation process. Additionally, the chip is capable of processing significantly smaller sample volumes than conventional methods and sample losses are eliminated due to decreased handling. Furthermore, the possibility of sample-to-sample contamination is reduced with the disposable format. The overall dimensions of the device were 22 mm by 60 mm by 1 mm, approximately the size of a standard microscope slide. The results indicate a cell purity of greater than 95% at a sample flow rate of 50 ml/h and a cell recovery of 81% at a sample flow rate of 10 ml/h. The cell purity was found to increase with increasing the sample flow rate. However, the cell recovery decreases with an increase in the flow rate. A parametric study was also performed to investigate the effects of channel height, substrate thickness, magnetic bead size, and number of beads per cell on the cell separation performance. V C 2013 AIP Publishing LLC. [http://dx

Isolation of cells for selective treatment and analysis using a magnetic microfluidic chip

“…Darabi et al employed an array of thin nickel stripes on a glass substrate excited by an array of external magnets to separate CD4 þ T cells from peripheral blood with 90% purity. 12 The magnetic elements can be either passive or active; passive elements are usually softferromagnetic structures, [13][14][15][16][17][18] while active elements are microelectromagnets. [19][20][21][22][23][24][25] Soft-ferromagnetic structures can be magnetized by applying an external magnetic field and demagnetized by removing the field.…”

Magnetophoretic-based microfluidic device for DNA isolation

“…A detailed description of the device fabrication and assembly has been described in an earlier publication and it is not repeated here for brevity. 21 Briefly, the device consists of a glass substrate on which a nickel grid is deposited and patterned. The fluidic channels were cut into a doublesided polyimide film.…”

“…These forces include hydrodynamic drag force, gravitational force, and magnetic force. There are varying assumptions made by researchers in this field but the ones that are the most common are a Newtonian fluid (for the sample or the buffer solution), 6 spherical magnetic particles, 21 non-rotational, 22 no slip conditions for the walls of the device, 23 and laminar flow. 24,25 The governing equations are Navier-Stokes for fluid flow and Maxwell's equations for magnetic fields.…”

“…These features have been shown to be effective in the separation of cells. 21 A schematic of the microfluidic device is shown in Fig. 1.…”

Magnetic Microfluidic Linear Halbach Array Configuration for Cell Separation

“…There are many researcher have studied the cells deformability and being able to sort different cells types based on those parameters [ [7]. All these techniques of particle and cell counting required methods to capture and sort particles in a liquid for sorting based on different properties.…”