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Nanofluidic Networks Expand Diagnostic Technology

AUTHOR: ND Staff

PUBLISHED: June 18, 2014

Small fluid samples need careful handling to preserve sample integrity. Some samples, like pheromones or neurotransmitters, are available only in limited quantities, and they can be destroyed during multi-step procedures. Others are small due to an aspect of the substance itself. For example, toxins must be handled in minute quantities to minimize potential harm to the diagnostician.

Paul Bohn
Paul W. Bohn

A team of University of Notre Dame researchers, led by Paul W. Bohn, the Arthur J. Schmitt Professor of Chemical and Biomolecular Engineering and concurrent professor of chemistry and biochemistry, has successfully addressed this challenge. They have developed platforms to capture individual molecules of interest in mass-limited quantities and created intelligent chemical reaction chambers in the space of a nanopore. Information can now be extracted from samples consisting of a few hundred-thousand molecules and manipulated as needed.

The team accomplished this by designing hybrid microfluidic/nanofluidic networks with nanoporous membranes in layered (3D) architectures. In previous studies at other research universities, devices had been limited to two microfluidic layers using a single layer of nanofluidic interconnects. Bohn’s hybrid networks with 3D architecture combine the advantages of traditional microfluidic devices with integrated-circuit-like capabilities, such as the ability to maintain separate, chemically unique environments within a single interconnected device, as well as the ability to transfer fluid between these two environments at will.

Each nanopore of a nanocapillary array membrane (NCAM) in the 3D hybrid microfluidic/nanofluidic system works as an intelligent chemical reaction chamber where substances can be loaded or unloaded externally via fluidic manipulation.

Each nanopore of a nanocapillary array membrane (NCAM) in the 3D hybrid microfluidic/nanofluidic system works as an intelligent chemical reaction chamber where substances can be loaded or unloaded externally via fluidic manipulation. The ability to confine mass-limited reactants within a nanopore also significantly increases the probability of a desired reaction. The use of chemical reaction chambers speeds up the reaction rate in cases where the kinetics is transport limited.

Notre Dame researchers’ success offers several possibilities for future lab-on-a-chip devices. For instance, a gated injection could be performed from a microchannel filled with a complex sample mixture into another channel where a preparative electrophoretic separation would be carried out. A specific component band could then be collected from this separation, transferred to yet another spatial plane and into a channel filled with a chiral separator where, after an additional separation, a specific enantiomer could be transferred to a final microchannel interface and a mass spectrometer for detection. Another possibility is an antibody-modified NCAM capturing a specific property from a complex sample mixture, thus performing a combined preparatory separation and de facto preconcentration, prior to an on-demand release by fluidic manipulation for further analytic steps.

SUGGESTED READING

Iannacone, J., Kim, B.-Y., Sweedler, J.V., King, T.L., and Bohn, P.W., “Manipulating Mass Limited Samples Using Hybrid Microfluidic/ nanofluidic Networks,” Biological Applications of Microfluidics, F.A. Gomez, ed., John Wiley & Sons, New York, 2008, Ch. 23, pp. 451-472.

Gatimu, E.N., Sweedler, J.V., and Bohn, P.W., “Nanofluidics and Mass-limited Chemical Analysis,” Analyst, 2006, 131, 705-709.

Kuo, T.C., Cannon, D.M. Jr., Feng, W., Shannon, M.A., Sweedler, J.V, and Bohn, P.W., “Gateable Nanofluidic Interconnects in Multilevel Microanalytical Systems,” Analytical Chemistry, 2003, 75, 1861-1867.