Richard Gillilan (Macromolecular Diffraction Facility, Cornell High Energy Synchrotron Source)
Detlef Smilgies (CHESS and Cornell Chemical Engineering)
X-ray small angle solution scattering on biological systems (BioSAXS) is a rapidly growing field in structural biology that has proven to be a powerful tool both in answering fundamental questions about living systems and in advancing drug development and delivery. Full characterization of biological samples using BioSAXS requires that a whole range of concentrations and buffer conditions (pH, salt concentration etc.) be examined with minimal sample consumption. This project will build upon our recent paper demonstrating in-situ sample concentration using a semipermeable membrane (Skou, M., Skou, S., Jensen, T. G., Vestergaard, B., & Gillilan, R. E. (2014). In situ microfluidic dialysis for biological small-angle X-ray scattering. Journal of Applied Crystallography, 47(4), 1355-1366).
Students with appropriate skills will examine one of more of the following problems:
1. Numerically solve the Navier-Stokes equations for full 3-dimensional models of microfluidic chips containing semi-permeable membranes. The resulting velocity fields will be used as input for (FiPy-based) solutions of the convection-diffusion equation for protein concentration. The student will explore possible chip designs that allow for both concentration and mass separation and will characterize possible tradeoffs and physical limitations (can we even have concentration and separation at the same time?).
2. Design and fabricate an asymmetric flow field flow fractionation (AF4) device that will attach to our existing chromatography pump and conduct a proof-of-concept test of the device as both a protein concentrator and as a possible separation device.
3. Use the same computational tools developed in (1) to investigate the maximum speed at which small-volume biological sample mixing (chaotic mixing regime) can be achieved within a microfluidic chip given realistic pressure constraints.
Students should have some knowledge of computational fluid mechanics and microfluidics and be able to recommend and use appropriate software for this project. Knowledge of Python is a plus since previous calculations used the FiPy package. Fabrication experience (production of engineering drawings, selection of materials, and machining) is also a plus, though designs generated by the student may be machined by CHESS staff as appropriate.