Percentages of proliferative P3 HCECs in the four seeding densities. HCECs were seeded at the densities of ‘LOW’, ‘MID’, ‘HIGH’, and ‘HIGH2×’. Proliferation rates of HCECs were assessed using Click-iT assay. D1: Donor 1. D2: Donor 2. D3: Donor 3. The differences in proliferation rates were not statistically significant. However, ANOVA analysis showed significant donor-to-donor variation (p < 0.05).