Research Highlights

Magnetophoretic Separation & Immunoassay

Magnetophoresis is a phenomenon explaining particle migration driven by magnetic force exerted on a particle. In a microchannel, magnetic force induced by an external magnetic field exerts an object to move toward the denser or sparser magnetic field. Previously, we have developed a new immunoassay system based on the magnetophoretic mobility of a microbead, depending on the amount of associated superparamagnetic nanoparticles under magnetic field gradient in a microfluidic channel [Lab Chip 2005, 5, 657]. By measuring the magnetophoretic deflection velocity of microbeads as the signal for the presence of analytes, the multiple disease biomarkers (such as allergen-specific IgEs or prostate-specific antigen) in a microchannel are simultaneously quantified by conjugated nanoparticles as a label [Anal. Chem. 2007, 79, 2214; Small 2009, 5, 2243]. In addition, the same technology  has been successfully applied to develop a magnetophoretic, continuous purification platform that rids single-walled carbon nanotubes (SWCNTs) of superparamagnetic iron-catalyst nanoparticles [Small 2007, 3, 1784]. We have also reported an improved magnetophoresis technique, called isomagnetophoresis, which discriminates subtle differences in magnetic susceptibility by using a magnetic susceptibility gradient in a microfluidic channel [JACS 2008, 130, 396]. The magnetic force exerted on a microbead is proportional to the magnetic susceptibility difference between the microbead and its surrounding solution, and the microbead moves toward or away from the high magnetic field in proportion to the magnetic susceptibility difference and stays at this isomagnetophoretic position. In isomagnetophoretic immunoassays, the magnetic nanoparticles are used as labels on microbeads in sandwich-type immunoassay, detecting the amount of bound analytes by isomagnetophoretic focusing the solid-support microbeads under the magnetic susceptibility gradient and magnetic field in a microchannel [Lab Chip 2011, 11, 2045]. The proposed immunoassay can be useful to accurately quantify the concentrations of biomarkers over the whole range of analyte concentrations, based on the current status and needs of the patient.

Related Articles:


Fengshan Shen, Je-Kyun Park, "Toxicity assessment of iron oxide nanoparticles based on cellular magnetic loading using magnetophoretic sorting in a trapezoidal microchannel," Anal. Chem., 90 (1), 920-927 (2018).  
External link Supporting Info. (Movie file zip, 22.8 MB)   


Younggeun Jo, Young Ki Hahn, Je-Kyun Park, "A magnetophoresis-based microfluidic platform under a static-fluid environment," Microfluid. Nanofluid., 21 (4), 74 (2017).


Younggeun Jo, Fengshan Shen, Young Ki Hahn, Ji-Ho Park, Je-Kyun Park, "Magnetophoretic sorting of single cell-containing microdroplets," Micromachines, 7 (4), 56 (2016).     OPEN ACCESS  
External link Highlighted in the MDPI blog (2016. 4. 22)



Chemical & Engineering News: Microfluidic Device Separates Unlabeled Cells (March 12, 2012)



Fengshan Shen, Hyundoo Hwang, Young Ki Hahn, Je-Kyun Park, "Label-free cell separation using a tunable magnetophoretic repulsion force," Anal. Chem., 84 (7), 3075-3081 (2012).  
External link
Supporting Info. (pdf, 159.2 KB)



Young Ki Hahn, Je-Kyun Park, "Versatile immunoassays based on isomagnetophoresis," Lab Chip, 11 (12), 2045-2048 (2011).    
External link Supporting Info. (pdf, 434 KB)
External link Selected for Vir. J. Bio. Phys. Res. (2011)/ Volume 21 / Issue 12 / INSTRUMENTATION DEVELOPMENT (2011. 6. 15)



Zongwen Jin, Young Ki Hahn, Eunkeu Oh, Young-Pil Kim, Je-Kyun Park, Seung Ho Moon, Jung-Tak Jang, Jinwoo Cheon, Hak-Sung Kim, "Magnetic nanoclusters for ultrasensitive magnetophoretic assays," Small, 5 (20), 2243-2246 (2009).   The first two authors contributed equally to this work.
External link Supporting Info. (pdf, 134 KB)


Joo H. Kang, Young Ki Hahn, Kyu Sung Kim, Je-Kyun Park, "Chapter 3. Magnetophoretic biosensing and separation using magnetic nanomaterials." In: Challa S. S. R. Kumar (ed), Magnetic Nanomaterials. Nanomaterials for the Life Sciences, Vol. 4. Wiley-VCH; pp. 77-118, 2009



Young Ki Hahn, Jae-Byum Chang, Zongwen Jin, Hak-Sung Kim, Je-Kyun Park, "Magnetophoretic position detection for multiplexed immunoassays using colored microspheres in a microchannel," Biosens. Bioelectron., 24 (7), 1870-1876 (2009).



Joo H. Kang, Sungyoung Choi, Wonhye Lee, Je-Kyun Park, "Isomagnetophoresis to discriminate subtle difference in magnetic susceptibility," J. Am. Chem. Soc., 130 (2), 396-397 (2008).  
External link Supporting Info. (pdf, 1.69 MB)



Joo H. Kang, Je-Kyun Park, "Magnetophoretic continuous purification of single-walled carbon nanotubes from catalytic impurities in a microfluidic device," Small, 3 (10), 1784-1791 (2007).



Young Ki Hahn, Zongwen Jin, Joo H. Kang, Eunkeu Oh, Min-Kyu Han, Hak-Sung Kim, Jung-Tak Jang, Jae-Hyun Lee, Jinwoo Cheon, Seung Hyun Kim, Hae-Sim Park, Je-Kyun Park, "Magnetophoretic immunoassay of allergen-specific IgE in an enhanced magnetic field gradient," Anal. Chem., 79 (6), 2214-2220 (2007).   The first two authors contributed equally to this work.



Kyu Sung Kim, Je-Kyun Park, "Superparamagnetic nanoparticle-based nanobiomolecular detection in a microfluidic channel," Curr. App. Phys., 6 (6), 976-981 (2006).


Kyu Sung Kim, Je-Kyun Park, "Magnetic force-based multiplexed immunoassay using superparamagnetic nanoparticles in microfluidic channel," Lab Chip, 5 (6), 657-664 (2005).  
External link Supporting Info. (doc, 838 KB)
This paper was selected as "The Most Cited Lab on a Chip Paper in Korea 2001-2010" at the 2010 Korea-EU Lab on a Chip Technology Workshop (9-10 September 2010, Seoul, Korea).