Magnetic nanoparticle-based technologies for lab-on-a-chip applications

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Abstract/Contents

Abstract
Lab-on-a-Chip devices are attractive for medical diagnostics due to their ability to perform laboratory tasks on small scales. This manuscript explores magnetic nanoparticle-based technologies for low-power, remote actuation in Lab-on-a-Chip systems. Two specific applications -- microfluidic pumping and cell separation -- are investigated. First, chemistry-independent microfluidic pumping using magnetic nanoparticles suspended within a fluid has been demonstrated. Magnetic circuits to generate magnetic field gradients for actuating superparamagnetic nanoparticles in fluids have been fabricated, and changes in fluid velocities when the magnetic circuits are applied have been measured. Results show that the fluid velocity in a microchannel increases 30 [mu]m/sec when a magnetic field gradient of ~3 T/m is applied, and 10 -- 70 [mu]m/sec when a magnetic field gradient of ~5 T/m is applied. The magnetic, optical, and mechanical properties of a magnetic polymer that is composed of SU-8 polymer embedded with nickel nanoparticles (SU8-Ni) have also been characterized. Results show the SU8-Ni composites exhibit weak ferromagnetic behavior and saturate at magnetic fields around 0.2 T, the transmittance of light through SU8-Ni decreases with increasing Ni concentrations, and SU8-Ni has a Young's modulus that is 30 times lower and a hardness that is 1400 times lower than that of bulk Ni. A torsional microactuator made of SU8-Ni has been fabricated to demonstrate its use for magnetic actuation, and a model of the SU8-Ni based on deflection experiments of the actuator has been developed. Micropillars made of SU8-Ni have been fabricated for capturing and concentrating breast cancer cells in microchannels. Magnetic field gradients up to 10,000 T/m have been predicted for an SU8-Ni pillar that is 100 [mu]m tall, 100 [mu]m in diameter, and composed of 12.5% Ni by weight. Experimental results show the SU8-Ni micropillars capture magnetic bead-bound cells when an external magnet is applied and release the cells when the magnet is removed.

Description

Type of resource text
Form electronic; electronic resource; remote
Extent 1 online resource.
Publication date 2010
Issuance monographic
Language English

Creators/Contributors

Associated with Tsai, Katherine Lin
Associated with Stanford University, Department of Electrical Engineering
Primary advisor Howe, Roger Thomas
Thesis advisor Howe, Roger Thomas
Thesis advisor Field, Leslie
Thesis advisor Pruitt, Beth
Thesis advisor Wang, Shan
Advisor Field, Leslie
Advisor Pruitt, Beth
Advisor Wang, Shan

Subjects

Genre Theses

Bibliographic information

Statement of responsibility Katherine Lin Tsai.
Note Submitted to the Department of Electrical Engineering.
Thesis Thesis (Ph.D.)--Stanford University, 2010.
Location electronic resource

Access conditions

Copyright
© 2010 by Katherine Lin Tsai
License
This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).

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