title: Tuning the mechanical properties of bioreducible multilayer films for improved cell adhesion and transfection activity.
abstract: A simple approach to the mechanical modulation of layer-by-layer (LbL) films is through manipulation of the film assembly. Here, we report results based on altering the salt concentration during film assembly and its effect on film rigidity. Based on changes in film rigidity, cell adhesion characteristics and transfection activity were investigated in vitro. LbL films consisting of reducible hyperbranched poly(amide amine) (RHB) have been implemented along with DNA for investigating fibroblast adhesion on [RHB/DNA](n/2) films with varying rigidities. The rigidity was varied by changing the ionic concentration of the deposition solution between 0.01 m NaCl and 1.0 m NaCl. Molecular force probe (MFP) measurements were performed to measure the apparent Young's modulus, E(APP), of the films in situ. Cell adhesion and stress-fiber characteristics were investigated using total internal reflectance microscopy (TIRF-M). The average cell peripheral area, fiber density and average fiber length during 5 days of cell growth on films with either low (below 2.0 MPa) or high (above 2.0 MPa) film elastic modulus were investigated. Transfection studies were performed using gfpDNA and SEAP-DNA to investigate if changes in cell adhesion affect transfection activity. Furthermore, cell proliferation and cytotoxicity studies were used to investigate cellular viability over a week. The results have shown that surface modification of bioreducible LbL films of controlled thickness and roughness promotes cellular adhesion, stress-fiber growth and increased transfection activity without the need for an additional adhesive protein pre-coating of the surface or chemical cross-linking of the film.
authors.affiliation: Max Planck Institute of Colloids and Interfaces, Department of Interfaces, Research Campus Golm, Potsdam, Germany. blacklock@mpikg.mpg.de
authors.forename: Jenifer
authors.initials: J
authors.lastname: Blacklock
authors.forename: Andreas
authors.initials: A
authors.lastname: Vetter
authors.forename: Andreas
authors.initials: A
authors.lastname: Lankenau
authors.forename: David
authors.initials: D
authors.lastname: Oupický
authors.forename: Helmuth
authors.initials: H
authors.lastname: Möhwald
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D002448:Cell Adhesion / Q000187:drug effects* / Q000502:physiology; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D008567:Membranes, Artificial; D051379:Mice; D018625:Microscopy, Atomic Force; D008856:Microscopy, Fluorescence; D041681:NIH 3T3 Cells; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D023822:Tissue Engineering; D014162:Transfection
chemical_list: D001672:Biocompatible Materials; D008567:Membranes, Artificial; D011108:Polymers