title: Responsive micromolds for sequential patterning of hydrogel microstructures.
abstract: Microscale hydrogels have been shown to be beneficial for various applications such as tissue engineering and drug delivery. A key aspect in these applications is the spatial organization of biological entities or chemical compounds within hydrogel microstructures. For this purpose, sequentially patterned microgels can be used to spatially organize either living materials to mimic biological complexity or multiple chemicals to design functional microparticles for drug delivery. Photolithographic methods are the most common way to pattern microscale hydrogels but are limited to photocrosslinkable polymers. So far, conventional micromolding approaches use static molds to fabricate structures, limiting the resulting shapes that can be generated. Herein, we describe a dynamic micromolding technique to fabricate sequentially patterned hydrogel microstructures by exploiting the thermoresponsiveness of poly(N-isopropylacrylamide)-based micromolds. These responsive micromolds exhibited shape changes under temperature variations, facilitating the sequential molding of microgels at two different temperatures. We fabricated multicompartmental striped, cylindrical, and cubic microgels that encapsulated fluorescent polymer microspheres or different cell types. These responsive micromolds can be used to immobilize living materials or chemicals into sequentially patterned hydrogel microstructures which may potentially be useful for a range of applications at the interface of chemistry, materials science and engineering, and biology.
authors.affiliation: Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Halil
authors.initials: H
authors.lastname: Tekin
authors.forename: Tonia
authors.initials: T
authors.lastname: Tsinman
authors.forename: Jefferson G
authors.initials: JG
authors.lastname: Sanchez
authors.forename: Brianna J
authors.initials: BJ
authors.lastname: Jones
authors.forename: Gulden
authors.initials: G
authors.lastname: Camci-Unal
authors.forename: Jason W
authors.initials: JW
authors.lastname: Nichol
authors.forename: Robert
authors.initials: R
authors.lastname: Langer
authors.forename: Ali
authors.initials: A
authors.lastname: Khademhosseini
mesh_terms: D000178:Acrylamides; D000180:Acrylic Resins; D004337:Drug Carriers / Q000737:chemistry; D020100:Hydrogels / Q000737:chemistry* / Q000627:therapeutic use; D054802:Molecular Imprinting / Q000379:methods*; D015394:Molecular Structure; D011108:Polymers; D013696:Temperature; D023822:Tissue Engineering / Q000379:methods
chemical_list: D000178:Acrylamides; D000180:Acrylic Resins; D004337:Drug Carriers; D020100:Hydrogels; D011108:Polymers; C052970:poly-N-isopropylacrylamide