Compact electromagnetically operated microfluidic system for detection of sub-200-nm magnetic labels for biosensing without external pumps

Morimoto, Yoshitaka; Takamura, Tsukasa; Sandhu, Adarsh

doi:10.1063/1.3352584

Cited by 5 publications

(6 citation statements)

References 7 publications

(4 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Morimoto et al [20] developed a microfluidic system where target mMBs were immobilized on a substrate and were used to capture columnar mMBs. NdFeB magnetic grains assembled onto a microfluidic chip to form alternating magnetic dipoles have been reported to efficiently remove magnetically tagged cells from suspension [19].…”

Section: Previous Studies and Designsmentioning

confidence: 99%

Efficient capture of magnetic microbeads by sequentially switched electroosmotic flow—an experimental study

Das

Al-Rjoub

Heineman

et al. 2016

J. Micromech. Microeng.

View full text Add to dashboard Cite

Magnetophoretic separation is a commonly used immunoassay technique in microfluidic platforms where magnetic microbeads (mMBs) coated with specific epitopes (antibodies) entrap target pathogens by antigen-antibody kinetics. The mMB-cell complexes are then separated from the continuous flow using an external magnetic field. The goal of this study was to design and test a microfluidic device for efficient separation of fluorescence-tagged mMBs driven by electroosmotic flow (EOF) under steady (time invariant) and switched (time varying) electric field conditions. The EOF was driven at electric fields of 100-180 V cm −1. The mMBs were captured by a neodymium (NdFeB) permanent earth magnet. The capture efficiency (η c) of these mMBs was improved by sequential switching of the applied electric field driven-EOF. The fluorescent images of the captured mMBs, obtained using an inverted epifluorescence microscope, were quantified using image processing tools. In steady EOF, induced by constant electric field, the number of captured mMBs decreased by 72.3% when the electric field was increased from 100 V cm −1 to 180 V cm −1. However, alternating the direction of flow through sequential switching of EOF increased the η c by bringing the escaped mMBs back to the capture zone and increasing their residence time in the area of higher magnetic fields. The average increase in η c was 54.3% for an mMB concentration of 1 × 10 6 beads ml −1 (C 1) and 41.6% for a concentration of 2 × 10 6 beads ml −1 (C 2). These improvements were particularly significant at higher electric fields where the η c with switching was, on average, ~70% more compared to flow without switching. The technique of sequential switching demonstrates an efficient method for capture of mMBs for application in magnetophoretic immunoassay.

show abstract

Section: Previous Studies and Designsmentioning

confidence: 99%

Efficient capture of magnetic microbeads by sequentially switched electroosmotic flow—an experimental study

Das

Al-Rjoub

Heineman

et al. 2016

J. Micromech. Microeng.

View full text Add to dashboard Cite

show abstract

“…To meet such a demand, we also investigated the use of our novel detection method in micro fluidic devices. More specifically, our detection method was carried out in micro channel made from poly-dimethylsiloxane (PDMS) [ 11 ].…”

Section: The Detection Via Columnar Particle Magnetically Capturedmentioning

confidence: 99%

“… ( a ) An aqueous solution containing superparamagnetic micrometer size columnar beads was dropped into one of reservoirs; ( b ) An electric field was applied across the channels to manipulate the columnar beads; ( c ) The external magnetic field was applied to the microfluidic chip to detect the 130-nm-diameter target beads immobilized on the surface of channels. Adapted from [ 11 ]. …”

Section: The Detection Via Columnar Particle Magnetically Capturedmentioning

confidence: 99%

“…( g , h ) Columnar particles begin to move through the microchannel again in the absence of an external magnetic field due to the electric force still acting on the columnar particles. Adapted from [ 11 ].…”

Section: The Detection Via Columnar Particle Magnetically Capturedmentioning

confidence: 99%

“…Here, we summarized our recent works related to magnetic detection by magnetic sensors [ 3 , 4 , 5 , 6 , 7 ]. We also describe novel techniques utilizing columnar magnetic particles to detect magnetic nano-sized particles which are difficult to observe by typical optical microscope and difficult to detect by magnetic sensor due to the sensor’s intrinsic noise [ 8 , 9 , 10 , 11 ]. Subsequently, two of our optical detection methods are presented [ 12 , 13 ].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Magnetic-Particle-Sensing Based Diagnostic Protocols and Applications

Takamura

Sharma

et al. 2015

Sensors

View full text Add to dashboard Cite

Magnetic particle-labeled biomaterial detection has attracted much attention in recent years for a number of reasons; easy manipulation by external magnetic fields, easy functionalization of the surface, and large surface-to-volume ratio, to name but a few. In this review, we report on our recent investigations into the detection of nano-sized magnetic particles. First, the detection by Hall magnetic sensor with lock-in amplifier and alternative magnetic field is summarized. Then, our approach to detect sub-200 nm diameter target magnetic particles via relatively large micoro-sized “columnar particles” by optical microscopy is described. Subsequently, we summarize magnetic particle detection based on optical techniques; one method is based on the scattering of the magnetically-assembled nano-sized magnetic bead chain in rotating magnetic fields and the other one is based on the reflection of magnetic target particles and porous silicon. Finally, we report recent works with reference to more familiar industrial products (such as smartphone-based medical diagnosis systems and magnetic removal of unspecific-binded nano-sized particles, or “magnetic washing”).

show abstract

Synthesis and applications of magnetic nanoparticles for biorecognition and point of care medical diagnostics

2010

View full text Add to dashboard Cite

Functionalized magnetic nanoparticles are important components in biorecognition and medical diagnostics. Here, we present a review of our contribution to this interdisciplinary research field. We start by describing a simple one-step process for the synthesis of highly uniform ferrite nanoparticles (d = 20-200 nm) and their functionalization with amino acids via carboxyl groups. For real-world applications, we used admicellar polymerization to produce 200 nm diameter 'FG beads', consisting of several 40 nm diameter ferrite nanoparticles encapsulated in a co-polymer of styrene and glycidyl methacrylate for high throughput molecular screening. The highly dispersive FG beads were functionalized with an ethylene glycol diglycidyl ether spacer and used for affinity purification of methotrexate-an anti-cancer agent. We synthesized sub-100 nm diameter magnetic nanocapsules by exploiting the self-assembly of viral capsid protein pentamers, where single 8, 20, and 27 nm nanoparticles were encapsulated with VP1 pentamers for applications including MRI contrast agents. The FG beads are now commercially available for use in fully automated bio-screening systems. We also incorporated europium complexes inside a polymer matrix to produce 140 nm diameter fluorescent-ferrite beads (FF beads), which emit at 618 nm. These FF beads were used for immunofluorescent staining for diagnosis of cancer metastases to lymph nodes during cancer resection surgery by labeling tumor cell epidermal growth factor receptor (EGFRs), and for the detection of brain natriuretic peptide (BNP)-a hormone secreted in excess amounts by the heart when stressed-to a level of 2.0 pg ml(-1). We also describe our work on Hall biosensors made using InSb and GaAs/InGaAs/AlGaAs 2DEG heterostructures integrated with gold current strips to reduce measurement times. Our approach for the detection of sub-200 nm magnetic bead is also described: we exploit the magnetically induced capture of micrometer sized 'probe beads' by nanometer sized 'target beads', enabling the detection of small concentrations of beads as small as 8 nm in 'pumpless' microcapillary systems. Finally, we describe a 'label-less homogeneous' procedure referred to as 'magneto-optical transmission (MT) sensing', where the optical transmission of a solution containing rotating linear chains of magnetic nanobeads was used to detect biomolecules with pM-level sensitivity with a dynamic range of more than four orders of magnitude. Our research on the synthesis and applications of nanoparticles is particularly suitable for point of care diagnostics.

show abstract

Compact electromagnetically operated microfluidic system for detection of sub-200-nm magnetic labels for biosensing without external pumps

Cited by 5 publications

References 7 publications

Efficient capture of magnetic microbeads by sequentially switched electroosmotic flow—an experimental study

Efficient capture of magnetic microbeads by sequentially switched electroosmotic flow—an experimental study

Magnetic-Particle-Sensing Based Diagnostic Protocols and Applications

Synthesis and applications of magnetic nanoparticles for biorecognition and point of care medical diagnostics

Contact Info

Product

Resources

About