(A) Islets were incubated with PLL, PPB[5], and PPB[2.5] at 1 mg/mL, and viability was assessed after various incubation times (mean ± standard deviation, *p < 0.05 compared to untreated controls). PLL exerted significant toxicity after only 15 min, while incubation with PPB[5] decreased islet viability slightly, but significantly, after 4 h. PPB[2.5] did not reduce islet viability even after a 12 h incubation (p > 0.05). (B) Representative confocal micrographs of islets stained with calcein AM (green, viable) and ethidum homodimer (red, nonviable) overlaid on bright field micrographs demonstrate changes in islet morphology associated with polycation-mediated cell death (from left to right: PLL, PPB[5], PPB[2.5]).