Single plane, confocal fluorescent images of rat islets cross-section 24 h post-encapsulation with 3-layer coatings (Images). Islet viability, via MTT metabolic assay, normalized to control (Graph). Groups: uncoated (Control); 3-layer coating using either PAMAM 15/0 (1), 15/20 (2), 15/30 (3), or 15/40 (4), interlayered with fluorescently-labeled hyperbranched Alg-N3; and NHS-PEG-N3, followed by 3-layer coating using PAMAM 15/40 interlayered with fluorescently-labeled hyperbranched Alg-N3. Error = standard deviation. Scale bar = 200 μm. * P < 0.05