Browsing by Author "Koh, Jaekyung"
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Item Open Access Activating an adaptive immune response from a hydrogel scaffold imparts regenerative wound healing.(Nature materials, 2021-04) Griffin, Donald R; Archang, Maani M; Kuan, Chen-Hsiang; Weaver, Westbrook M; Weinstein, Jason S; Feng, An Chieh; Ruccia, Amber; Sideris, Elias; Ragkousis, Vasileios; Koh, Jaekyung; Plikus, Maksim V; Di Carlo, Dino; Segura, Tatiana; Scumpia, Philip OMicroporous annealed particle (MAP) scaffolds are flowable, in situ crosslinked, microporous scaffolds composed of microgel building blocks and were previously shown to accelerate wound healing. To promote more extensive tissue ingrowth before scaffold degradation, we aimed to slow MAP degradation by switching the chirality of the crosslinking peptides from L- to D-amino acids. Unexpectedly, despite showing the predicted slower enzymatic degradation in vitro, D-peptide crosslinked MAP hydrogel (D-MAP) hastened material degradation in vivo and imparted significant tissue regeneration to healed cutaneous wounds, including increased tensile strength and hair neogenesis. MAP scaffolds recruit IL-33 type 2 myeloid cells, which is amplified in the presence of D-peptides. Remarkably, D-MAP elicited significant antigen-specific immunity against the D-chiral peptides, and an intact adaptive immune system was required for the hydrogel-induced skin regeneration. These findings demonstrate that the generation of an adaptive immune response from a biomaterial is sufficient to induce cutaneous regenerative healing despite faster scaffold degradation.Item Open Access Enhanced In Vivo Delivery of Stem Cells using Microporous Annealed Particle Scaffolds.(Small (Weinheim an der Bergstrasse, Germany), 2019-09) Koh, Jaekyung; Griffin, Donald R; Archang, Maani M; Feng, An-Chieh; Horn, Thomas; Margolis, Michael; Zalazar, David; Segura, Tatiana; Scumpia, Philip O; Di Carlo, DinoDelivery to the proper tissue compartment is a major obstacle hampering the potential of cellular therapeutics for medical conditions. Delivery of cells within biomaterials may improve localization, but traditional and newer void-forming hydrogels must be made in advance with cells being added into the scaffold during the manufacturing process. Injectable, in situ cross-linking microporous scaffolds are recently developed that demonstrate a remarkable ability to provide a matrix for cellular proliferation and growth in vitro in three dimensions. The ability of these scaffolds to deliver cells in vivo is currently unknown. Herein, it is shown that mesenchymal stem cells (MSCs) can be co-injected locally with microparticle scaffolds assembled in situ immediately following injection. MSC delivery within a microporous scaffold enhances MSC retention subcutaneously when compared to cell delivery alone or delivery within traditional in situ cross-linked nanoporous hydrogels. After two weeks, endothelial cells forming blood vessels are recruited to the scaffold and cells retaining the MSC marker CD29 remain viable within the scaffold. These findings highlight the utility of this approach in achieving localized delivery of stem cells through an injectable porous matrix while limiting obstacles of introducing cells within the scaffold manufacturing process.