title: Femtosecond laser micro-machined polyimide films for cell scaffold applications.
abstract: Engineering of sophisticated synthetic 3D scaffolds that allow controlling behaviour and location of the cells requires advanced micro/nano-fabrication techniques. Ultrafast laser micro-machining employing a 1030-nm wavelength Yb:KGW femtosecond laser and a micro-fabrication workstation for micro-machining of commercially available 12.7 and 25.4 μm thickness polyimide (PI) film was applied. Mechanical properties of the fabricated scaffolds, i.e. arrays of differently spaced holes, were examined via custom-built uniaxial micro-tensile testing and finite element method simulations. We demonstrate that experimental micro-tensile testing results could be numerically simulated and explained by two-material model, assuming that 2-6 μm width rings around the holes possessed up to five times higher Young's modulus and yield stress compared with the rest of the laser intacted PI film areas of 'dog-bone'-shaped specimens. That was attributed to material modification around the micro-machined holes in the vicinity of the position of the focused laser beam track during trepanning drilling. We demonstrate that virgin PI films provide a suitable environment for the mobility, proliferation and intercellular communication of human bone marrow mesenchymal stem cells, and discuss how cell behaviour varies on the micro-machined PI films with holes of different diameters (3.1, 8.4 and 16.7 μm) and hole spacing (30, 35, 40 and 45 μm). We conclude that the holes of 3.1 μm diameter were sufficient for metabolic and genetic communication through membranous tunneling tubes between cells residing on the opposite sides of PI film, but prevented the trans-migration of cells through the holes. Copyright © 2016 John Wiley & Sons, Ltd.
authors.affiliation: Institute of Cardiology of Lithuanian University of Health Sciences, Sukilėlių Ave. 17, LT-50009, Lithuania.
authors.forename: Ieva
authors.initials: I
authors.lastname: Antanavičiūtė
authors.affiliation: Institute of Materials Science of Kaunas University of Technology, K. Baršausko, Str. 59, LT-51423, Kaunas, Lithuania.
authors.forename: Linas
authors.initials: L
authors.lastname: Šimatonis
authors.affiliation: Institute of Materials Science of Kaunas University of Technology, K. Baršausko, Str. 59, LT-51423, Kaunas, Lithuania.
authors.forename: Orestas
authors.initials: O
authors.lastname: Ulčinas
authors.affiliation: Institute of Materials Science of Kaunas University of Technology, K. Baršausko, Str. 59, LT-51423, Kaunas, Lithuania.
authors.forename: Aušra
authors.initials: A
authors.lastname: Gadeikytė
authors.affiliation: Institute of Materials Science of Kaunas University of Technology, K. Baršausko, Str. 59, LT-51423, Kaunas, Lithuania.
authors.forename: Brigita
authors.initials: B
authors.lastname: Abakevičienė
authors.affiliation: Institute of Materials Science of Kaunas University of Technology, K. Baršausko, Str. 59, LT-51423, Kaunas, Lithuania.
authors.forename: Sigitas
authors.initials: S
authors.lastname: Tamulevičius
authors.affiliation: Institute of Cardiology of Lithuanian University of Health Sciences, Sukilėlių Ave. 17, LT-50009, Lithuania.
authors.forename: Valeryia
authors.initials: V
authors.lastname: Mikalayeva
authors.affiliation: Institute of Cardiology of Lithuanian University of Health Sciences, Sukilėlių Ave. 17, LT-50009, Lithuania.
authors.forename: Vytenis Arvydas
authors.initials: VA
authors.lastname: Skeberdis
authors.affiliation: Institute of Physiology and Pharmacology of Lithuanian University of Health Sciences, A. Mickevičiaus Str. 9, LT-44307, Kaunas, Lithuania.
authors.forename: Edgaras
authors.initials: E
authors.lastname: Stankevičius
authors.affiliation: Institute of Materials Science of Kaunas University of Technology, K. Baršausko, Str. 59, LT-51423, Kaunas, Lithuania.
authors.forename: Tomas
authors.initials: T
authors.lastname: Tamulevičius
mesh_terms: D001696:Biomechanical Phenomena; D002450:Cell Communication / Q000187:drug effects; D055119:Elastic Modulus; D020342:Finite Element Analysis; D006801:Humans; D007094:Imides / Q000494:pharmacology*; D007834:Lasers; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D055616:Microtechnology; D013718:Tensile Strength; D013997:Time Factors; D054457:Tissue Scaffolds / Q000737:chemistry*
chemical_list: D007094:Imides
keywords: Young's modulus; femtosecond laser; intercellular communication; membranous tunneling tubes; mesenchymal stem cells; micro-machining; polyimide film