title: Optical tweezers applied to a microfluidic system.
abstract: We will demonstrate how optical tweezers can be combined with a microfluidic system to create a versatile microlaboratory. Cells are moved between reservoirs filled with different media by means of optical tweezers. We show that the cells, on a timescale of a few seconds, can be moved from one reservoir to another without the media being dragged along with them. The system is demonstrated with an experiment where we expose E. coli bacteria to different fluorescent markers. We will also discuss how the system can be used as an advanced cell sorter. It can favorably be used to sort out a small fraction of cells from a large population, in particular when advanced microscopic techniques are required to distinguish various cells. Patterns of channels and reservoirs were generated in a computer and transferred to a mask using either a sophisticated electron beam technique or a standard laser printer. Lithographic methods were applied to create microchannels in rubber silicon (PDMS). Media were transported in the channels using electroosmotic flow. The optical system consisted of a combined confocal and epi-fluorescence microscope, dual optical tweezers and a laser scalpel.
authors.affiliation: Department of Physics, Chalmers University of Technology and Goteborg University, SE-412 96 Göteborg, Sweden.
authors.forename: Jonas
authors.initials: J
authors.lastname: Enger
authors.forename: Mattias
authors.initials: M
authors.lastname: Goksör
authors.forename: Kerstin
authors.initials: K
authors.lastname: Ramser
authors.forename: Petter
authors.initials: P
authors.lastname: Hagberg
authors.forename: Dag
authors.initials: D
authors.lastname: Hanstorp
mesh_terms: D002469:Cell Separation / Q000295:instrumentation; D003584:Cytological Techniques / Q000295:instrumentation*; D004926:Escherichia coli / Q000378:metabolism / Q000648:ultrastructure; D005456:Fluorescent Dyes; D007834:Lasers; D044085:Microfluidics / Q000295:instrumentation*; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D011419:Propidium / Q000378:metabolism
chemical_list: D005456:Fluorescent Dyes; D011419:Propidium