Next Article in Journal
Robust Tracking of a Cost-Effective Micro-Stereolithography System Based on a Compliant Nanomanipulator
Previous Article in Journal
Imine Reductase Based All-Enzyme Hydrogel with Intrinsic Cofactor Regeneration for Flow Biocatalysis
Previous Article in Special Issue
Continuous-Flow Separation and Efficient Concentration of Foodborne Bacteria from Large Volume Using Nickel Nanowire Bridge in Microfluidic Chip
Open AccessArticle

Configuration and Design of Electromagnets for Rapid and Precise Manipulation of Magnetic Beads in Biosensing Applications

Faculty of Engineering, Bar-Ilan University, Ramat Gan 5290002, Israel
*
Author to whom correspondence should be addressed.
Micromachines 2019, 10(11), 784; https://doi.org/10.3390/mi10110784
Received: 6 October 2019 / Revised: 5 November 2019 / Accepted: 13 November 2019 / Published: 15 November 2019
(This article belongs to the Special Issue Magnetic Biosensors)
Rapid and precise manipulation of magnetic beads on the nano and micro scales is essential in many biosensing applications, such as separating target molecules from background molecules and detecting specific proteins and DNA sequences in plasma. Accurately moving magnetic beads back and forth requires at least two adjustable magnetic field gradients. Unlike permanent magnets, electromagnets are easy to design and can produce strong and adjustable magnetic field gradients without mechanical motion, making them desirable for use in robust and safe medical devices. However, using multiple magnetic field sources to manipulate magnetic beads presents several challenges, including overlapping magnetic fields, added bulk, increased cost, and reduced durability. Here, we provide a thorough analysis, including analytical calculations, numerical simulations, and experimental measurements, of using two electromagnets to manipulate magnetic beads inside a miniature glass cell. We analyze and experimentally demonstrate different aspects of the electromagnets’ design, such as their mutual influence, the advantages and disadvantages of different pole tip geometries, and the correlation between the electromagnets’ positions and the beads’ aggregation during movement. Finally, we have devised a protocol to maximize the magnetic forces acting on magnetic beads in a two-electromagnet setup while minimizing the electromagnets’ size. We used two such electromagnets in a small footprint magnetic modulation biosensing system and detected as little as 13 ng/L of recombinant Zika virus antibodies, which enables detection of Zika IgM antibodies as early as 5 days and as late as 180 days post symptoms onset, significantly extending the number of days that the antibodies are detectable. View Full-Text
Keywords: magnetic tweezers; magnetic beads; biosensing; pole tip; Zika virus magnetic tweezers; magnetic beads; biosensing; pole tip; Zika virus
Show Figures

Figure 1

MDPI and ACS Style

Stern, M.; Cohen, M.; Danielli, A. Configuration and Design of Electromagnets for Rapid and Precise Manipulation of Magnetic Beads in Biosensing Applications. Micromachines 2019, 10, 784.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop