University PhD Dissertation Defense
"Interrogating, manipulating, and controlling nano-bio interfaces"
Jules J. VanDersarl
Department of Materials Science & Engineering
Advisor: Prof. Nicholas A. Melosh
Thursday, May 26th, 2011
1:00 pm
(Refreshments at 12:45pm)
Location: Paul G. Allen Auditorium (CIS-X 101)
http://campus-map.stanford.edu/index.cfm?ID=04-055
Cells communicate through direct contact and soluble chemical signals. Mimicking an extracellular environment requires controlling these signals at micron length scales. Integrated circuits make electronic control at these scales trivial, but fluidic control at these length scales requires very different principles. Standard microfluidic devices can finely control flowing fluids, but fluid flow affects cells in a myriad of ways. Alternatively, diffusion based chemical delivery methods tend to be crude, ill defined systems that offer very limited control.
Our lab has developed several techniques that combine the active spatial and temporal control of microfluidic systems with a delivery system that relies purely on diffusion. First, we show a silicon based array of nanoreservoirs underneath the cell culture surface which are used to store and release bioactive molecules. These reservoirs are opened and closed with electrochemical dissolution and deposition at a narrow reservoir opening. Next, we show an adaptation of traditional, elastomer based microfluidics. In these devices the cell culture area is separated from a microfluidic channel located directly underneath the chamber by a nanoporous membrane. The desirable microfluidic properties, including temporal and spatial control, are preserved, while fluidic flow over the cells is eliminated. Finally, we demonstrate a novel "nanostraw" culture surface, which is combined with the previous device to offer fluidic access directly to the cell cytosol, creating a powerful tool with implications for cell delivery and sampling.
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