(464f) Massively Scaled Microfluidic Device for the Flow-Based Formation of 3D Perfusable Scaffold

Miscible and immiscible liquids have been previously used to define and spatially organize microscale building blocks in planar microchannel networks [1, 2]. Although many applications, including tissue engineering, ultimately require three-dimensional organization, most efforts so far have been limited to planar approaches. The layer-by-layer microfabrication of microstructured materials has been achieved [3], although complex and highly organized three-dimensional microstructures have yet to be fully demonstrated.

We present a microfluidic strategy for the continuous in-flow formation of a soft material with a three-dimensionally organized and tunable microstructure. Our approach is enabled by a massively scaled microfluidic device. A soft lithography process was adapted to consecutively define 300micron wide and 100micron deep microchannels in ten 500micron thin elastomer substrates [4]. The device fabrication was completed by vertically bonding the obtained ten layers. Two fluids, aqueous alginate, A, and calcium chloride, C, entered the device at defined flow rates through separate inlets after which they were distributed into an array of ten by ten microchannels. An alternating configuration of A channels surrounded by C channels was obtained at the device exit where a complex fluid was produced. The three-dimensionally organized fluid was extruded into a water reservoir, in a continuous process. Diffusion of C initiated the polymerization of A, defining the soft material matrix and leaving a vascularized flow network in the areas initially occupied by C. A 10cm long microstructured sample was obtained in less than four minutes. Upon completion of the polymerization process, the microfluidic device was used to perfuse the vascularized sample.

REFERENCES:

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2. M. T. Tolley, M. Krishnan, D. Erickson, and H. Lipson, ?Dynamically Programmable Fluidic Assembly?, Appl. Phys. Lett., 93, 254105 (2008)

3. N.W. Choi, M. Cabodi, B. Held, J.P. Gleghorn, L.J. Bonassar, and A.D. Stroock, ?Microfluidic Scaffolds for Tissue Engineering?, Nature Mat., 6, 11 (2007)

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