title: A photoreversible protein-patterning approach for guiding stem cell fate in three-dimensional gels.
abstract: Although biochemically patterned hydrogels are capable of recapitulating many critical aspects of the heterogeneous cellular niche, exercising spatial and temporal control of the presentation and removal of biomolecular signalling cues in such systems has proved difficult. Here, we demonstrate a synthetic strategy that exploits two bioorthogonal photochemistries to achieve reversible immobilization of bioactive full-length proteins with good spatial and temporal control within synthetic, cell-laden biomimetic scaffolds. A photodeprotection-oxime-ligation sequence permits user-defined quantities of proteins to be anchored within distinct subvolumes of a three-dimensional matrix, and an ortho-nitrobenzyl ester photoscission reaction facilitates subsequent protein removal. By using this approach to pattern the presentation of the extracellular matrix protein vitronectin, we accomplished reversible differentiation of human mesenchymal stem cells to osteoblasts in a spatially defined manner. Our protein-patterning approach should provide further avenues to probe and direct changes in cell physiology in response to dynamic biochemical signalling.
authors.affiliation: 1] Division of Chemistry and Chemical Engineering California Institute of Technology, 1200 East California Boulevard Pasadena, California 91125, USA [2] Department of Chemical Engineering, University of Washington, 4000 15th Avenue NE Seattle, Washington 98195, USA.
authors.forename: Cole A
authors.initials: CA
authors.lastname: DeForest
authors.affiliation: Division of Chemistry and Chemical Engineering California Institute of Technology, 1200 East California Boulevard Pasadena, California 91125, USA.
authors.forename: David A
authors.initials: DA
authors.lastname: Tirrell
mesh_terms: D040761:Biomimetic Materials / Q000737:chemistry*; D002454:Cell Differentiation; D006801:Humans; D020100:Hydrogels / Q000737:chemistry*; D055767:Immobilized Proteins / Q000737:chemistry*; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000378:metabolism*; D010006:Osteoblasts / Q000166:cytology / Q000378:metabolism*; D055668:Photochemical Processes; D054457:Tissue Scaffolds / Q000737:chemistry; D019096:Vitronectin / Q000737:chemistry
chemical_list: D020100:Hydrogels; D055767:Immobilized Proteins; D019096:Vitronectin