title: Biogrid--a microfluidic device for large-scale enzyme-free dissociation of stem cell aggregates.
abstract: Culturing stem cells as free-floating aggregates in suspension facilitates large-scale production of cells in closed systems, for clinical use. To comply with GMP standards, the use of substances such as proteolytic enzymes should be avoided. Instead of enzymatic dissociation, the growing cell aggregates may be mechanically cut at passage, but available methods are not compatible with large-scale cell production and hence translation into the clinic becomes a severe bottle-neck. We have developed the Biogrid device, which consists of an array of micrometerscale knife edges, micro-fabricated in silicon, and a manifold in which the microgrid is placed across the central fluid channel. By connecting one side of the Biogrid to a syringe or a pump and the other side to the cell culture, the culture medium with suspended cell aggregates can be aspirated, forcing the aggregates through the microgrid, and ejected back to the cell culture container. Large aggregates are thereby dissociated into smaller fragments while small aggregates pass through the microgrid unaffected. As proof-of-concept, we demonstrate that the Biogrid device can be successfully used for repeated passage of human neural stem/progenitor cells cultured as so-called neurospheres, as well as for passage of suspension cultures of human embryonic stem cells. We also show that human neural stem/progenitor cells tolerate transient pressure changes far exceeding those that will occur in a fluidic system incorporating the Biogrid microgrids. Thus, by using the Biogrid device it is possible to mechanically passage large quantities of cells in suspension cultures in closed fluidic systems, without the use of proteolytic enzymes.
authors.affiliation: Division of Nanobiotechnology, Department of Measurement Technology and Industrial Electrical Engineering, Lund University, P.O. Box 118, S-22100 Lund, Sweden.
authors.forename: Lars
authors.initials: L
authors.lastname: Wallman
authors.forename: Elisabet
authors.initials: E
authors.lastname: Åkesson
authors.forename: Dario
authors.initials: D
authors.lastname: Ceric
authors.forename: Per Henrik
authors.initials: PH
authors.lastname: Andersson
authors.forename: Kelly
authors.initials: K
authors.lastname: Day
authors.forename: Outi
authors.initials: O
authors.lastname: Hovatta
authors.forename: Scott
authors.initials: S
authors.lastname: Falci
authors.forename: Thomas
authors.initials: T
authors.lastname: Laurell
authors.forename: Erik
authors.initials: E
authors.lastname: Sundström
mesh_terms: D018929:Cell Culture Techniques / Q000295:instrumentation / Q000379:methods; D049109:Cell Proliferation; D002478:Cells, Cultured; D053595:Embryonic Stem Cells / Q000166:cytology; D006801:Humans; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation / Q000379:methods*; D058953:Neural Stem Cells / Q000166:cytology*; D011312:Pressure; D012825:Silicon / Q000737:chemistry
chemical_list: D012825:Silicon