title: A controlled-release strategy for the generation of cross-linked hydrogel microstructures.
abstract: Microscale hydrogels of controlled sizes and shapes are useful for cell-based screening, in vitro diagnostics, tissue engineering, and drug delivery. However, the rapid cross-linking of many chemically and pH cross-linkable hydrogel materials prevents the application of existing micromolding techniques. In this work we present a method for fabricating micromolded calcium alginate and chitosan structures through controlled release of the gelling agent from a hydrogel mold. Replica molding was employed to generate patterned membranes, whereas microtransfer molding was used to produce microparticles of controlled shapes. To explore the viability of this technique for producing complex tissue engineering micro-architectures, this approach was used to generate cell-laden size- and shape-controlled 3D microgels as well as composite hydrogels with well-defined spatially segregated regions. In addition, shape-controlled microstructures that can exhibit differential release properties were loaded with macromolecules to verify the potential of this approach for drug delivery applications.
authors.affiliation: Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Giovanni Talei
authors.initials: GT
authors.lastname: Franzesi
authors.forename: Bin
authors.initials: B
authors.lastname: Ni
authors.forename: Yibo
authors.initials: Y
authors.lastname: Ling
authors.forename: Ali
authors.initials: A
authors.lastname: Khademhosseini
mesh_terms: D000464:Alginates / Q000138:chemical synthesis / Q000737:chemistry*; D000818:Animals; D048271:Chitosan / Q000138:chemical synthesis / Q000737:chemistry*; D003432:Cross-Linking Reagents / Q000737:chemistry; D003692:Delayed-Action Preparations / Q000138:chemical synthesis* / Q000737:chemistry; D053595:Embryonic Stem Cells / Q000166:cytology; D016650:Fluorescein-5-isothiocyanate / Q000031:analogs & derivatives / Q000737:chemistry; D020723:Glucuronic Acid / Q000138:chemical synthesis / Q000737:chemistry; D022781:Hepatocytes / Q000166:cytology; D006603:Hexuronic Acids / Q000138:chemical synthesis / Q000737:chemistry; D020100:Hydrogels / Q000138:chemical synthesis* / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008567:Membranes, Artificial; D051379:Mice; D041681:NIH 3T3 Cells; D010316:Particle Size; D012235:Rhodamines / Q000737:chemistry; D012710:Serum Albumin, Bovine / Q000737:chemistry; D023822:Tissue Engineering / Q000379:methods
chemical_list: D000464:Alginates; D003432:Cross-Linking Reagents; D003692:Delayed-Action Preparations; D006603:Hexuronic Acids; D020100:Hydrogels; D008567:Membranes, Artificial; D012235:Rhodamines; C039217:fluorescein isothiocyanate bovine serum albumin; D012710:Serum Albumin, Bovine; D020723:Glucuronic Acid; D048271:Chitosan; D016650:Fluorescein-5-isothiocyanate