Bioorthogonal layer-by-layer encapsulation of pancreatic islets via hyperbranched polymers.
Encapsulation of viable tissues via layer-by-layer polymer assembly provides a versatile platform for cell surface engineering, with nanoscale control over the capsule properties. Herein, we report the development of a hyperbranched polymer-based, ultrathin capsule architecture expressing bioorthogonal functionality and tailored physiochemical properties. Random carbodiimide-based condensation of 3,5-dicarboxyphenyl glycineamide on alginate yielded a highly branched polysaccharide with multiple, spatially restricted, and readily functionalizable terminal carboxylate moieties. Poly(ethylene glycol) (PEG) was utilized to link azido end groups to the structured alginate. Together with a phosphine-functionalized poly(amidoamine) dendrimer, nanoscale layer-by-layer coatings, covalently stabilized via Staudinger ligation, were assembled onto solid surfaces and pancreatic islets. The effects of electrostatic and/or bioorthogonal covalent interlayer interactions on the resulting coating efficiency and stability, as well as pancreatic islet viability and function, were studied. These hyperbranched polymers provide a flexible platform for the formation of covalently stabilized, ultrathin coatings on viable cells and tissues. In addition, the hyperbranched nature of the polymers presents a highly functionalized surface capable of bioorthogonal conjugation of additional bioactive or labeling motifs.
Diabetes Research Institute, University of Miami , Miami, Florida 33136 United States.
Kerim M
KM
Gattás-Asfura
Cherie L
CL
Stabler
D000464:Alginates / Q000737:chemistry; D000818:Animals; D002214:Capsules / Q000737:chemistry* / Q000633:toxicity; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D050091:Dendrimers / Q000737:chemistry; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D007515:Islets of Langerhans / Q000166:cytology*; D010720:Phosphines / Q000737:chemistry; D011073:Polyamines / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry*; D051381:Rats; D011917:Rats, Inbred Lew; D012825:Silicon / Q000737:chemistry; D013499:Surface Properties
D000464:Alginates; D002214:Capsules; D050091:Dendrimers; D006603:Hexuronic Acids; D010720:Phosphines; C531249:Poly(amidoamine); D011073:Polyamines; D011108:Polymers; D011092:Polyethylene Glycols; D020723:Glucuronic Acid; D012825:Silicon