title: A microfluidic system in combination with optical tweezers for analyzing rapid and reversible cytological alterations in single cells upon environmental changes.
abstract: We report on the development of an experimental platform where epi-fluorescence microscopy and optical tweezers are combined with a microfluidic system to enable the analysis of rapid cytological responses in single cells. The microfluidic system allows two different media to be merged in a Y-shaped channel. Microscale channel dimensions ensure purely laminar flow and, as a result, an environmental gradient can be created between the two media. Optical tweezers are used to move a single trapped cell repeatedly between the different environments. The cell is monitored continuously by fluorescence microscopy during the experiment. In a first experiment on yeast (Saccharomyces cerevisiae) we observed changes in cell volume as the cell was moved between environments with different osmolarity. This demonstrated that the platform allowed analysis of cytological alterations on a time scale shorter than 0.2 s. In a second experiment we observed the spatial migration of the Yap1p transcription factor fused to GFP as a cell was moved from an environment of low to high oxidative capacity. The system is universal allowing the response to numerous environmental changes to be studied on the sub second time scale in a variety of model cells. We intend to use the platform to study how the age of cells, their progression through the cell cycle, or their genetic landscape, alter their capacity (kinetics and amplitude) to respond to environmental changes.
authors.affiliation: Department of Physics, Göteborg University, SE-412 96, Göteborg, Sweden.
authors.forename: Emma
authors.initials: E
authors.lastname: Eriksson
authors.forename: Jonas
authors.initials: J
authors.lastname: Enger
authors.forename: Bodil
authors.initials: B
authors.lastname: Nordlander
authors.forename: Nika
authors.initials: N
authors.lastname: Erjavec
authors.forename: Kerstin
authors.initials: K
authors.lastname: Ramser
authors.forename: Mattias
authors.initials: M
authors.lastname: Goksör
authors.forename: Stefan
authors.initials: S
authors.lastname: Hohmann
authors.forename: Thomas
authors.initials: T
authors.lastname: Nyström
authors.forename: Dag
authors.initials: D
authors.lastname: Hanstorp
mesh_terms: D003470:Culture Media; D003584:Cytological Techniques / Q000295:instrumentation / Q000379:methods; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation / Q000379:methods; D008856:Microscopy, Fluorescence; D052898:Optical Tweezers; D012441:Saccharomyces cerevisiae / Q000166:cytology*
chemical_list: D003470:Culture Media