ABSTRACT
Pancreatic islet transplantation is an effective treatment for type I diabetes mellitus. However, many problems associated with pancreatic islet engraftment remain unresolved. In this study, we developed a hydrogel microwell device for islet implantation, fabricated by crosslinking gelatin-methacryloyl (GelMA) and 2-hydroxyethyl methacrylate (HEMA) in appropriate proportions. The fabricated hydrogel microwell device could be freeze-dried and restored by immersion in the culture medium at any time, allowing long-term storage and transport of the device for ready-to-use applications. In addition, due to its non-swelling properties, the shape of the wells of the device was maintained. Thus, the device allowed pancreatic ß cell lines to form spheroids and increase insulin secretion. Intraperitoneal implantation of the ß cell line-seeded GelMA/HEMA hydrogel microwell device reduced blood glucose levels in diabetic mice. In addition, they were easy to handle during transplantation and were removed from the transplant site without peritoneal adhesions or infiltration by inflammatory cells. These results suggest that the GelMA/HEMA hydrogel microwell device can go from spheroid and/or organoid fabrication to transplantation in a single step.
Subject(s)
Gelatin , Hydrogels , Insulin-Secreting Cells , Methacrylates , Animals , Mice , Insulin-Secreting Cells/metabolism , Insulin-Secreting Cells/cytology , Methacrylates/chemistry , Hydrogels/chemistry , Gelatin/chemistry , Spheroids, Cellular , Diabetes Mellitus, Experimental/therapy , Islets of Langerhans Transplantation , Blood Glucose/metabolism , Blood Glucose/analysis , Insulin/metabolism , Polyhydroxyethyl Methacrylate/chemistry , Diabetes Mellitus, Type 1/therapyABSTRACT
Extracellular environments significantly affect cell proliferation, differentiation, and functions. The extracellular environment changes during many physiological and pathological processes such as embryo development, wound healing, and tumor growth. To mimic these changes, we developed novel thiol-maleimide clickable alginate microcapsules, which can introduce thiol-containing peptides by " in situ conjugation" with maleimide-modified alginate, even in serum-containing cell culture media. Additive peptides were rapidly concentrated into microcapsules by a diffusion-reaction process in the capsule. The proliferation of encapsulated fibroblasts was accelerated by in situ conjugation of CRGDS, while free RGDS showed no effect. Moreover, encapsulated preosteoblastic cells started osteogenic differentiation via in situ conjugation of BMP-2 mimetic peptides such as CDWIVA and CG-BMP-2 knuckle epitope peptide, while BMP-2 did not induce differentiation of the encapsulated cells. Especially in tissue engineering, accurate and inexpensive methods for inducing cell differentiation are required. We believe that this in situ conjugation approach employing various functional peptides will be useful in biomedical, bioindustrial, and biochemical fields in the future.