Several assays were conducted to assist in the assessment of the microencapsulated cells’ biological activity induced by glucose. Assays including glucose-induced cellular insulin release studies with an ultrasensitive mouse insulin ELISA kit (Mercodia Cooperation, Uppsala, Sweden) and MTT studies were used to assess glucose-induced viability. MTT reagent, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (Sigma Chemical Co. St. Louis, MO, USA) was utilised in a validated method, previously established by the laboratory, allowing accurate assessment of cell viability in microcapsules without having to rupture the capsules [33 (link),34 (link)]. Measurements of antioxidant activity were taken using a plate reader (Enspire, PerkinElmer, Waltham, MA, USA) for fluorescence, with increased fluorescent readings indicating increased oxidative stress, and therefore, decreased antioxidant activity. Oxidative stress measurements were taken from oxidized radical species following incubation with a mixture of dichloro-dihydro-fluorescein diacetate and 2,2′-azobis-2-methyl-propanimidamide dihydrochloride [25 (link),37 (link),38 (link)]. Assessments were taken under glycaemic and hyperglycaemic conditions.
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