title: Neutrophil chemotaxis in linear and complex gradients of interleukin-8 formed in a microfabricated device.
abstract: Although a wealth of knowledge about chemotaxis has accumulated in the past 40 years, these studies have been hampered by the inability of researchers to generate simple linear gradients instantaneously and to maintain them at steady state. Here we describe a device microfabricated by soft lithography and consisting of a network of microfluidic channels that can generate spatially and temporally controlled gradients of chemotactic factors. When human neutrophils are positioned within a microchannel, their migration in simple and complex interleukin-8 (IL-8) gradients can be tested. The cells exhibit strong directional migration toward increasing concentrations of IL-8 in linear gradients. Neutrophil migration halts abruptly when cells encounter a sudden drop in the chemoattractant concentration to zero ("cliff" gradient). When neutrophils are challenged with a gradual increase and decrease in chemoattractant ("hill" gradient), however, the cells traverse the crest of maximum concentration and migrate further before reversing direction. The technique described in this paper provides a robust method to investigate migratory cells under a variety of conditions not accessible to study by earlier techniques.
authors.affiliation: Center for Engineering in Medicine and Surgical Services, Massachusetts General Hospital, Harvard Medical School, and Shriners Hospitals for Children, Boston, MA 02114, USA.
authors.forename: Noo
authors.initials: N
authors.lastname: Li Jeon
authors.forename: Harihara
authors.initials: H
authors.lastname: Baskaran
authors.forename: Stephan K W
authors.initials: SK
authors.lastname: Dertinger
authors.forename: George M
authors.initials: GM
authors.lastname: Whitesides
authors.forename: Livingston
authors.initials: L
authors.lastname: Van de Water
authors.forename: Mehmet
authors.initials: M
authors.lastname: Toner
mesh_terms: D001681:Biological Assay / Q000295:instrumentation* / Q000379:methods; D018929:Cell Culture Techniques / Q000295:instrumentation; D002630:Chemotactic Factors / Q000494:pharmacology*; D002634:Chemotaxis, Leukocyte / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004867:Equipment Design; D016209:Interleukin-8 / Q000494:pharmacology*; D008832:Microchemistry; D008904:Miniaturization; D009504:Neutrophils / Q000166:cytology* / Q000187:drug effects*
chemical_list: D002630:Chemotactic Factors; D016209:Interleukin-8