title: Microcirculation within grooved substrates regulates cell positioning and cell docking inside microfluidic channels.
abstract: Immobilization of cells inside microfluidic devices is a promising approach for enabling studies related to drug screening and cell biology. Despite extensive studies in using grooved substrates for immobilizing cells inside channels, a systematic study of the effects of various parameters that influence cell docking and retention within grooved substrates has not been performed. We demonstrate using computational simulations that the fluid dynamic environment within microgrooves significantly varies with groove width, generating microcirculation areas in smaller microgrooves. Wall shear stress simulation predicted that shear stresses were in the opposite direction in smaller grooves (25 and 50 microm wide) in comparison to those in wider grooves (75 and 100 microm wide). To validate the simulations, cells were seeded within microfluidic devices, where microgrooves of different widths were aligned perpendicularly to the direction of the flow. Experimental results showed that, as predicted, the inversion of the local direction of shear stress within the smaller grooves resulted in alignment of cells on two opposite sides of the grooves under the same flow conditions. Also, the amplitude of shear stress within microgrooved channels significantly influenced cell retainment in the channels. Therefore, our studies suggest that microscale shear stresses greatly influence cellular docking, immobilization, and retention in fluidic systems and should be considered for the design of cell-based microdevices.
authors.affiliation: Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, 65 Landsdowne Street, Room 252, Cambridge, MA 02139, USA.
authors.forename: Amir
authors.initials: A
authors.lastname: Manbachi
authors.forename: Shamit
authors.initials: S
authors.lastname: Shrivastava
authors.forename: Margherita
authors.initials: M
authors.lastname: Cioffi
authors.forename: Bong Geun
authors.initials: BG
authors.lastname: Chung
authors.forename: Matteo
authors.initials: M
authors.lastname: Moretti
authors.forename: Utkan
authors.initials: U
authors.lastname: Demirci
authors.forename: Marjo
authors.initials: M
authors.lastname: Yliperttula
authors.forename: Ali
authors.initials: A
authors.lastname: Khademhosseini
mesh_terms: D018929:Cell Culture Techniques / Q000295:instrumentation* / Q000379:methods; D002468:Cell Physiological Phenomena; D003198:Computer Simulation; D004867:Equipment Design; D019544:Equipment Failure Analysis; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation* / Q000379:methods; D013499:Surface Properties; D046888:Tissue Array Analysis / Q000295:instrumentation*