title: In situ cell manipulation through enzymatic hydrogel photopatterning.
abstract: The physicochemical properties of hydrogels can be manipulated in both space and time through the controlled application of a light beam. However, methods for hydrogel photopatterning either fail to maintain the bioactivity of fragile proteins and are thus limited to short peptides, or have been used in hydrogels that often do not support three-dimensional (3D) cell growth. Here, we show that the 3D invasion of primary human mesenchymal stem cells can be spatiotemporally controlled by micropatterning the hydrogel with desired extracellular matrix (ECM) proteins and growth factors. A peptide substrate of activated transglutaminase factor XIII (FXIIIa)--a key ECM crosslinking enzyme--is rendered photosensitive by masking its active site with a photolabile cage group. Covalent incorporation of the caged FXIIIa substrate into poly(ethylene glycol) hydrogels and subsequent laser-scanning lithography affords highly localized biomolecule tethering. This approach for the 3D manipulation of cells within gels should open up avenues for the study and manipulation of cell signalling.
authors.affiliation: 1] Institute of Bioengineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland [2].
authors.forename: Katarzyna A
authors.initials: KA
authors.lastname: Mosiewicz
authors.forename: Laura
authors.initials: L
authors.lastname: Kolb
authors.forename: André J
authors.initials: AJ
authors.lastname: van der Vlies
authors.forename: Mikaël M
authors.initials: MM
authors.lastname: Martino
authors.forename: Philipp S
authors.initials: PS
authors.lastname: Lienemann
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Hubbell
authors.forename: Martin
authors.initials: M
authors.lastname: Ehrbar
authors.forename: Matthias P
authors.initials: MP
authors.lastname: Lutolf
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D060846:Cell Engineering / Q000379:methods*; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism; D026122:Factor XIIIa / Q000737:chemistry* / Q000378:metabolism*; D006801:Humans; D020100:Hydrogels / Q000737:chemistry*; D008027:Light; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000378:metabolism; D051379:Mice; D055616:Microtechnology; D010782:Photolysis; D011092:Polyethylene Glycols / Q000737:chemistry; D011817:Rabbits
chemical_list: D004800:Enzymes, Immobilized; D020100:Hydrogels; D011092:Polyethylene Glycols; D026122:Factor XIIIa