title: Three-dimensional microfiber devices that mimic physiological environments to probe cell mechanics and signaling.
abstract: Many physiological systems are regulated by cells that alter their behavior in response to changes in their biochemical and mechanical environment. These cells experience this dynamic environment through an endogenous biomaterial matrix that transmits mechanical force and permits chemical exchange with the surrounding tissue. As a result, in vitro systems that mimic three-dimensional, in vivo cellular environments can enable experiments that reveal the nuanced interplay between biomechanics and physiology. Here we report the development of a minimal-profile, three-dimensional (MP3D) experimental microdevice that confines cells to a single focal plane, while allowing the precise application of mechanical displacement to cells and concomitant access to the cell membrane for perfusion with biochemical agonists. The MP3D device--an ordered microfiber scaffold erected on glass--provides a cellular environment that induces physiological cell morphologies. Small manipulations of the scaffold's microfibers allow attached cells to be mechanically probed. Due to the scaffold's minimal height profile, MP3D devices confine cells to a single focal plane, facilitating observation with conventional epifluorescent microscopy. When examining fibroblasts within MP3D devices, we observed robust cellular calcium responses to both a chemical stimulus as well as mechanical displacement of the cell membrane. The observed response differed significantly from previously reported, mechanically-induced calcium responses in the same cell type. Our findings demonstrate a key link between environment, cell morphology, mechanics, and intracellular signal transduction. We anticipate that this device will broadly impact research in fields including biomaterials, tissue engineering, and biophysics.
authors.affiliation: Department of Biomedical Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213, USA.
authors.forename: Warren C
authors.initials: WC
authors.lastname: Ruder
authors.forename: Erica D
authors.initials: ED
authors.lastname: Pratt
authors.forename: Sasha
authors.initials: S
authors.lastname: Bakhru
authors.forename: Metin
authors.initials: M
authors.lastname: Sitti
authors.forename: Stefan
authors.initials: S
authors.lastname: Zappe
authors.forename: Chao-Min
authors.initials: CM
authors.lastname: Cheng
authors.forename: James F
authors.initials: JF
authors.lastname: Antaki
authors.forename: Philip R
authors.initials: PR
authors.lastname: LeDuc
mesh_terms: D000818:Animals; D020013:Calcium Signaling / Q000502:physiology; D060833:Cellular Microenvironment / Q000502:physiology*; D003584:Cytological Techniques / Q000295:instrumentation* / Q000379:methods*; D005456:Fluorescent Dyes / Q000737:chemistry; D040542:Mechanotransduction, Cellular / Q000502:physiology; D051379:Mice; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation*; D018613:Microscopy, Confocal; D041681:NIH 3T3 Cells; D011126:Polypropylenes / Q000737:chemistry; D054457:Tissue Scaffolds / Q000737:chemistry*
chemical_list: D005456:Fluorescent Dyes; D011126:Polypropylenes