Native Magnetic Properties Research Articles

Six-stage cascade paramagnetic mode magnetophoretic separation system for human blood samples

This paper is focused on the development of a six-stage cascade paramagnetic mode magnetophoretic separation (PMMS) system for separating suspended cells in blood based on their native magnetic properties. The design and fabrication of a PMMS system are presented and the microfluidic separation system is characterized experimentally using human whole blood as the case study. The PMMS system can separate blood cells types continuously using the magnetophoretic force produced from a high magnetic field gradient without magnetic or fluorescent tagging. Experimental results demonstrated that red blood cell separation in the PMMS system at a volumetric flow rate of 28.8 microL/hr, resulting in a separation time of 10.4 min for a 5.0 microL blood sample with a separation efficiency of 89.5 +/- 0.20%. The PMMS system was tested at higher volumetric flow rates of 50.4 microL/hr and 72.0 microL/hr. The measured separation efficiencies were 86.2 +/- 1.60% and 59.9 +/- 6.06% respectively.

Lateral-driven continuous magnetophoretic separation of blood cells

We present a method for the lateral-driven continuous magnetophoretic separation of red and white blood cells from peripheral whole blood, based on their native magnetic properties. The separation is achieved using a high-gradient magnetic field, caused by a ferromagnetic wire array inlaid on glass substrate. The wire array creates an even lateral magnetophoretic force on the whole area of the microchannel, improving the separation efficiency and throughput. When the flow rate and external magnetic flux were 20 μl/h and 0.3 T, respectively, the microseparator continuously separated out 93.9% of red blood cells and 89.2% of white blood cells from the whole blood.

혈액 세포의 고유자성을 이용한 마이크로 자기영동 세포분리기

This paper presents the characterization of a continuous magnetophoretic microseparator for separating white and red blood cells from peripheral whole blood cells based on their native magnetic properties. The magnetophoretic microseparator separated the blood cells using a high gradient magnetic separation (HGMS) method without the use of additives such as magnetic beads or probing materials. Experimental results show that the paramagnetic capture mode microseparator can continuously separate out 93.5% of red blood cells and 97.4% of white blood cells from diluted whole blood, and the diamagnetic capture mode microseparator can continuously separate out 89.7% of red blood cells and 72.7 % of white blood cells by using applying an external magnetic flux of 0.2 T using a permanent magnet.

A glass microfluidic chip for continuous blood cell sorting by a magnetic gradient without labeling

This paper presents a microfluidic chip for highly efficient separation of red blood cells (RBCs) from whole blood on the basis of their native magnetic properties. The glass chip was fabricated by photolithography and thermal bonding. It consisted of one inlet and three outlets, and a nickel wire of 69-microm diameter was positioned in the center of a separation channel with 149-microm top width and 73-microm depth by two parallel ridges (about 10 microm high). The two ridges were formed simultaneously during the wet etching of the channels. The nickel wire for generating the magnetic gradient inside the separation channel was introduced from the side of the chip through a guide channel. The external magnetic field was applied by a permanent magnet of 0.3 T placed by the side of the chip and parallel to the main separation channel. The RBCs were separated continuously from the 1:40 (v/v) diluted blood sample at a flow rate in the range 0.12-0.92 microL/min (9-74 mm/min) with the chip, and up to 93.7% of the RBCs were collected in the middle outlet under a flow rate of 0.23 microL/min. The cell sedimentation was alleviated by adjusting the specific density of the supporting media with bovine serum albumin. Quantum dot labeling was introduced for visual fluorescence tracking of the separation process. The uneven distribution phenomenon of the blood cells around the nickel wire was reported and discussed.

Microsystems for isolation and electrophysiological analysis of breast cancer cells from blood

This paper presents the development of a microsystem for separating suspended breast cancer cells in peripheral blood and for sorting them based on their electrophysiological characteristics. A continuous paramagnetic capture mode (PMC) magnetophoretic microseparator was utilized for the isolation of suspended breast cancer cells in peripheral blood based on the native magnetic properties of blood cells without any tagging such as with magnetic probes. A micro-electrical impedance spectroscopy (mu-EIS) system was used as a downstream cell analysis tool to extract the pathological characteristics from the breast cancer cells. The system was fabricated on silicon and glass substrates utilizing microfabrication and stereolithography technologies. The experimental results of the PMC microseparator show that 94.8% of the breast cancer cells could be continuously separated out from a spiked blood sample with a 0.2 T external magnetic flux. The electrical impedances of human breast cancer cell lines of different pathological stages (MCF-7, MDA-MB-231, and MDA-MB-435) were measured using mu-EIS and compared to those of normal human breast tissue cell line MCF-10A.

Paramagnetic capture mode magnetophoretic microseparator for blood cells

The paper presents the characterisation of a continuous paramagnetic capture (PMC) mode magnetophoretic microseparator for separating red and white blood cells from whole blood based on their native magnetic properties. The PMC microseparator separates the blood cells using a high-gradient magnetic separation method without the use of additives such as magnetic tagging. The microseparator is fabricated using microfabrication technology, enabling the integration of micro-scale magnetic flux concentrators in an aqueous micro-environment. Experimental results show that the PMC microseparator can continuously separate out 91.1% of red blood cells from whole blood within 5 min, using an external magnetic flux of 0.2 T from a permanent magnet. Monitoring of white blood cells dyed with a fluorescent probe shows that 87.7% of white blood cells are separated out by the 0.2 T external magnetic flux applied to the PMC microseparator.

Paramagnetic capture mode magnetophoretic microseparator for high efficiency blood cell separations

This paper presents the characterization of continuous single-stage and three-stage cascade paramagnetic capture (PMC) mode magnetophoretic microseparators for high efficiency separation of red and white blood cells from diluted whole blood based on their native magnetic properties. The separation mechanism for both PMC microseparators is based on a high gradient magnetic separation (HGMS) method. This approach enables separation of blood cells without the use of additives such as magnetic beads. Experimental results for the single-stage PMC microseparator show that 91.1% of red blood cells were continuously separated from the sample at a volumetric flow rate of 5 microl h-1. In addition, the three-stage cascade PMC microseparator continuously separated 93.5% of red blood cells and 97.4% of white blood cells from whole blood at a volumetric flow rate of 5 microl h-1.

Diamagnetic capture mode magnetophoretic microseparator for blood cells

This paper presents the characterization of a continuous diamagnetic capture (DMC) mode magnetophoretic microseparator for separating red and white blood cells from diluted whole blood based on their native magnetic properties. The DMC microseparator separated the blood cells using a high-gradient magnetic separation (HGMS) method without the use of additives such as magnetic beads. The microseparator was fabricated using microfabrication technology, enabling the integration of microscale magnetic flux concentrators in an aqueous microenvironment. Experimental results show that the DMC microseparator can continuously separate out 89.7% of red blood cells (RBCs) from diluted whole blood within 5 min using an external magnetic flux of 0.2 T from a permanent magnet. Monitoring white blood cells (WBCs) probed with a fluorescence dye show that 72.7% of WBCs were separated out within 10 min in the DMC microseparator using a 0.2 T external applied magnetic flux. Consequently, the DMC microseparator may facilitate the separation of WBCs from whole blood in applications such as a genetic sample preparation and blood borne disease detection. [1574].

Continuous magnetophoretic separation of blood cells in microdevice format

This paper presents a method for continuous magnetophoretic separation of red and white blood cells from whole blood based on their native magnetic properties. The microsystem separates the blood cells using a high gradient magnetic separation method without the use of additives such as magnetic tagging or inducing agents. A theoretical model of the magnetophoretic microseparator is derived and verified by comparison with finite element simulation. The microseparator is fabricated using microfabrication technology, enabling the integration of microscale magnetic flux concentrators in an aqueous microenvironment, providing strong magnetic forces, and fast separations. Experimental tests are performed using a permanent magnet to create an external magnetic flux of 0.2T, and measuring the movement of red blood cells within the microchannel of the microseparator. The experimental results correlate well with the theoretical results.