title: Calcium pre-conditioning substitution enhances viability and glucose sensitivity of pancreatic beta-cells encapsulated using polyelectrolyte multilayer coating method.
abstract: Type I diabetics are dependent on daily insulin injections. A therapy capable of immunoisolating pancreatic beta-cells and providing normoglycaemia is an alternative since it would avoid the late complications associated with insulin use. Here, 3D-concave agarose micro-wells were used to culture robust pancreatic MIN-6 cell spheroids within 24 hours that were shown to exhibit cell-cell contact and uniform size (201 ± 2 μm). A polyelectrolyte multilayer (PEM) approach using alginate and poly-l-lysine was employed to coat cell spheroids. In comparison to conventional PEM, use of a novel Ca2+pre-coating step enhanced beta-cells viability (89 ± 6%) and metabolic activity since it reduced the toxic effect of the cationic polymer. Pre-coating was achieved by treating MIN-6 spheroids with calcium chloride, which enabled the adhesion of anionic polymer to the cells surface. Pre-coated cells coated with four bilayers of polymers were successfully immunoisolated from FITC-mouse antibody and pro-inflammatory cytokines. Novel PEM coated cells were shown to secret significantly (P < 0.05) different amounts of insulin in response to changes in glucose concentration (2 vs. 20 mM). This work presents a 3D culture model and novel PEM coating procedure that enhances viability, maintains functionality and immunoisolates beta-cells, which is a promising step towards an alternative therapy to insulin.
authors.affiliation: School of Chemical Engineering, University of Birmingham, Birmingham, B15 2TT, UK.
authors.forename: Niusha
authors.initials: N
authors.lastname: Nikravesh
authors.affiliation: School of Chemical Engineering, University of Birmingham, Birmingham, B15 2TT, UK.
authors.forename: Sophie C
authors.initials: SC
authors.lastname: Cox
authors.affiliation: School of Chemical Engineering, University of Birmingham, Birmingham, B15 2TT, UK.
authors.forename: Gurpreet
authors.initials: G
authors.lastname: Birdi
authors.affiliation: School of Chemical Engineering, University of Birmingham, Birmingham, B15 2TT, UK.
authors.forename: Richard L
authors.initials: RL
authors.lastname: Williams
authors.affiliation: School of Chemical Engineering, University of Birmingham, Birmingham, B15 2TT, UK.
authors.forename: Liam M
authors.initials: LM
authors.lastname: Grover
mesh_terms: D000464:Alginates; D002118:Calcium / Q000378:metabolism*; D018929:Cell Culture Techniques; D002470:Cell Survival; D018914:Cells, Immobilized / Q000187:drug effects* / Q000502:physiology*; D005947:Glucose / Q000378:metabolism*; D050417:Insulin-Secreting Cells / Q000187:drug effects* / Q000502:physiology*; D011107:Polylysine / Q000031:analogs & derivatives*; D018874:Spheroids, Cellular
chemical_list: D000464:Alginates; C051546:alginate-polylysine-alginate; D011107:Polylysine; D005947:Glucose; D002118:Calcium