title: Cross polarization compatible dialysis chip.
abstract: We visualize birefringence in microliter sample volumes using a microfluidic dialysis chip optimized for cross polarization microscopy. The chip is composed of two overlapping polydimethylsiloxane (PDMS) channels separated by a commercial cellulose ester membrane. Buffer exchange in the sample chamber is achieved within minutes by dialyzing under continuous reservoir flow. Using fd virus as a birefringent model system, we monitor the fd virus isotropic to liquid crystal phase transition as a function of ionic strength. We show that the reorientation of the fd virus spans a few tens of seconds, indicative of fast ion exchange across the membrane. Complete phase separation reorganization takes minutes to hours as it involves diffusive virus mass transport within the storage chamber.
authors.affiliation: The Raymond and Beverly Sackler School of Physics and Astronomy, Tel-Aviv University, 69978 Tel Aviv, Israel. roy@post.tau.ac.il.
authors.forename: Micha
authors.initials: M
authors.lastname: Kornreich
authors.forename: Michael
authors.initials: M
authors.lastname: Heymann
authors.forename: Seth
authors.initials: S
authors.lastname: Fraden
authors.forename: Roy
authors.initials: R
authors.lastname: Beck
mesh_terms: D001718:Birefringence; D008567:Membranes, Artificial; D017551:Microdialysis / Q000295:instrumentation*; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation*
chemical_list: D008567:Membranes, Artificial