Fig. 4. Cell proliferation assays and cargo delivery. (a) Cell viability as a function of PSNA dose for primary human myoblasts and HEK293T cells. After incubation for 24 h with 10, 100 and 10,000 PSNAs per cell, cell proliferation was measured using a CellTiter (MTS) assay. Data presented is mean and SD (n = 4); samples were compared using a two-way ANOVA with Bonferroni's multiple comparison test. (b) Time-course cell proliferation assay using primary human myoblasts. Proliferation of primary human myoblasts was measured after 24, 48 and 72 h incubation with 15,000 PSNAs per cell and compared to untreated control. Data are presented as mean and SD (n = 4); samples were compared using a two-way ANOVA with Bonferroni's multiple comparison test. (c) Time-course cell proliferation assay using HEK293T cells. Conditions as (b). *p < 0.05, ***p < 0.001. (d) Delivery of Rhodamine 6G to human primary fibroblasts. 50,000 primary human fibroblasts per well were treated 24 h before imaging with 10¹⁰ PSNAs loaded with rhodamine during PSNA vesicle formation. Treated samples were compared with cells treated with an empty PSNA control. Images are representative. Scale bars 400 μm (10× images), 100 μm (40× images).