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Nanoporous elements in microfluidics for multi-scale separation of bioparticles

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dc.contributor.advisor Mehmet Toner. en_US Chen, Grace Dongqing en_US
dc.contributor.other Harvard--MIT Program in Health Sciences and Technology. en_US 2012-09-13T19:37:20Z 2012-09-13T19:37:20Z 2012 en_US 2012 en_US
dc.description Thesis (Ph. D. in Biomedical Engineering)--Harvard-MIT Program in Health Sciences and Technology, 2012. en_US
dc.description Cataloged from PDF version of thesis. en_US
dc.description Includes bibliographical references (p. 103-112). en_US
dc.description.abstract The efficient isolation of specific bioparticles in lab-on-a-chip platforms is important for many applications in clinical diagnostics and biomedical research. The majority of microfluidic devices designed for specific particle isolation are constructed of solid materials such as silicon, glass, or polymers. Such devices are hampered by some critical challenges: the low efficiency of particle-surface interactions in affinity based particle capture, the difficulty in accessing sub-micron particles, and design inflexibility between platforms for different particle sizes. Existing porous materials do not offer the structural properties or patterning capabilities to address these challenges. This work introduces Vertically Aligned Carbon Nanotubes (VACNTs) as a new porous material in microfluidics, and demonstrates the different ways in which it can improve bioparticle separation across both the micro and nano size scales. Our devices are fabricated by integrating patterned VACNT forests with ultra-high (99%) porosity inside of microfluidic channels. We demonstrated both mechanical and chemical capture of particles ranging over three orders of magnitude in size using simple device geometries. Nanoparticles below the inter-nanotube spacing (80 nm) of the forest can penetrate inside the forest and interact with the large surface area created by individual nanotubes. For larger particles (>80 nm), the ultra-high porosity of the nanotube elements enhances particlestructure interactions on the outer surface of the patterned nanoporous elements. We showed using both modeling and experiment that this enhancement is achieved through two mechanisms: the increase of direct interception and the reduction of near-surface hydrodynamic resistance. We verified that the improvement of interception efficiency also results in an increase in capture efficiency when comparing nanoporous VACNT post arrays with solid PDMS post arrays of the same geometry, using both bacteria and cells as model systems. The technology developed in this thesis can provide improved control of bioseparation processes to access a wide range of bioparticles, opening new pathways for both research and point-of-care diagnostics. en_US
dc.description.statementofresponsibility by Grace Dongqing Chen. en_US
dc.format.extent 112 p. en_US
dc.language.iso eng en_US
dc.publisher Massachusetts Institute of Technology en_US
dc.rights M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. en_US
dc.rights.uri en_US
dc.subject Harvard--MIT Program in Health Sciences and Technology. en_US
dc.title Nanoporous elements in microfluidics for multi-scale separation of bioparticles en_US
dc.type Thesis en_US Biomedical Engineering en_US
dc.contributor.department Harvard--MIT Program in Health Sciences and Technology. en_US
dc.identifier.oclc 809083196 en_US

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