title: Sensing and Sensibility: Single-Islet-based Quality Control Assay of Cryopreserved Pancreatic Islets with Functionalized Hydrogel Microcapsules.
abstract: Despite decades of research and clinical studies of islet transplantations, finding simple yet reliable islet quality assays that correlate accurately with in vivo potency is still a major challenge, especially for real-time and single-islet-based quality assessment. Herein, proof-of-concept studies of a cryopreserved microcapsule-based quality control assays are presented for single islets. Individual rat pancreatic islets and fluorescent oxygen-sensitive dye (FOSD) are encapsulated in alginate hydrogel microcapsules via a microfluidic device. To test the susceptibility of the microcapsules and the FOSD to cryopreservation, the islet microcapsules containing FOSD are cryopreserved and the islet functionalities (adenosine triphosphate, static insulin release measurement, and oxygen consumption rate) are assessed after freezing and thawing steps. The cryopreserved islet capsules with FOSD remain functional after encapsulation and freezing/thawing procedures, validating a simple yet reliable individual-islet-based quality control method for the entire islet processing procedure prior to transplantation. This work also demonstrates that the functionality of cryopreserved islets can be improved by introducing trehalose into the routinely used cryoprotectant dimethyl sulfoxide. The functionalized alginate hydrogel microcapsules with embedded FOSD and optimized cryopreservation protocol presented in this work serve as a versatile islet quality assay and offer tremendous promise for tackling existing challenges in islet transplantation procedures.
authors.affiliation: School of Materials Science and Engineering, Wuhan University of Technology, Wuhan, Hubei, 430070, China.
authors.forename: Wanyu
authors.initials: W
authors.lastname: Chen
authors.affiliation: Department of Mechanical Engineering, University of Washington, Seattle, WA, 98195, USA.|School of Mechanical and Materials Engineering, Washington State University, Everett, 98201, WA, USA.
authors.forename: Zhiquan
authors.initials: Z
authors.lastname: Shu
authors.affiliation: Department of Mechanical Engineering, University of Washington, Seattle, WA, 98195, USA.
authors.forename: Dayong
authors.initials: D
authors.lastname: Gao
authors.affiliation: Micro/Bio/Nanofluidics Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, 904-0495, Japan.
authors.forename: Amy Q
authors.initials: AQ
authors.lastname: Shen
mesh_terms: D000818:Animals; D001681:Biological Assay / Q000379:methods*; D002214:Capsules; D015925:Cryopreservation; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000494:pharmacology*; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D007515:Islets of Langerhans / Q000187:drug effects / Q000502:physiology*; D010101:Oxygen Consumption / Q000187:drug effects; D011786:Quality Control; D017207:Rats, Sprague-Dawley
chemical_list: D002214:Capsules; D007328:Insulin; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate
keywords: FOSD; cryopreservation; droplet microfluidics; fluorescent oxygen-sensitive dyes; quality control assays; single-islet capsules