title: Electric field stimulation through a substrate influences Schwann cell and extracellular matrix structure.
abstract: OBJECTIVE
  Electric field (EF) stimulation has been used to cue cell growth for tissue engineering applications. In this study, we explore the electrical parameters and extracellular mechanisms that elicit changes in cell behavior when stimulated through the substrate.
  
  
  METHODS
  Rat Schwann cell morphology was compared when exposed to EF through the media or a conductive indium tin oxide substrate. Ionic and structural effects were then analyzed on Matrigel and collagen I, respectively.
  
  
  RESULTS
  When stimulating through media, cells had greater alignment perpendicular to the EF with higher current densities (106 mA cm(-2) at 245 mV mm(-1)), and reached maximum alignment within 8 h. Stimulation through the substrate with EF (up to 110 mV mm(-1)) did not affect Schwann cell orientation, however the EF caused extracellular matrix (ECM) coatings on substrates to peel away, suggesting EF can physically change the ECM. Applying alternating current (ac) 2-1000 Hz signals through the media or substrate both caused cells to flatten and protrude many processes, without preferential alignment. Matrigel exposed to a substrate EF of 10 mV mm(-1) for 2 h had a greater calcium concentration near the cathode, but quickly dissipated when the EF was removed. Schwann cells seeded 7 d after gels were exposed to substrate EF still aligned perpendicular to the EF direction. Microscopy of collagen I exposed to substrate EF shows alignment and bundling of fibrils.
  
  
  CONCLUSIONS
  These findings demonstrate EF exposure can control Schwann cell alignment and morphology, change ECM bulk/surface architecture, and align ECM structures.
authors.affiliation: Department of Biomedical Engineering, The University of Texas at Austin, 107 W. Dean Keeton, 1 University Station C0800, Austin, TX 78712, USA.
authors.forename: Hieu T
authors.initials: HT
authors.lastname: Nguyen
authors.forename: Claudia
authors.initials: C
authors.lastname: Wei
authors.forename: Jacqueline K
authors.initials: JK
authors.lastname: Chow
authors.forename: Lindsey
authors.initials: L
authors.lastname: Nguy
authors.forename: Hieu K
authors.initials: HK
authors.lastname: Nguyen
authors.forename: Christine E
authors.initials: CE
authors.lastname: Schmidt
mesh_terms: D000818:Animals; D020013:Calcium Signaling / Q000502:physiology* / Q000528:radiation effects; D016764:Cell Polarity / Q000502:physiology / Q000528:radiation effects; D049109:Cell Proliferation / Q000528:radiation effects; D048429:Cell Size / Q000528:radiation effects; D002478:Cells, Cultured; D004558:Electric Stimulation / Q000379:methods*; D005109:Extracellular Matrix / Q000502:physiology* / Q000528:radiation effects / Q000648:ultrastructure*; D011829:Radiation Dosage; D051381:Rats; D012583:Schwann Cells / Q000502:physiology* / Q000528:radiation effects