Fig. 3: The central LCD segment of NCAP forms ThS fluorescent PS droplet that transition into amorphous and fibrous solid-like particles.

a Brightfield (BF) and Thioflavin-S (ThS) fluorescence (green) microscopy images of 40:1 and 4:1 LCD: hairpin-Site2 (S2hp) vRNA molar ratio mixtures incubated for ~0.5, 2, 6 h and 4 days. b Mean area (purple) and mean circularity (blue; normalized to particle size) of droplets and particles quantified from a series of light microscopy images of 40:1 and 4:1 LCD: S2hp mixtures imaged at day 1–4 of incubation. The experiment was performed in three biological repeats, each with technical triplicates. Five images were collected for every technical replicate. Boxplots show the 25th percentile, median, and 75th percentile of the mean values for triplicate experiments. The whiskers extend to the most extreme data points. Observations beyond the whisker length, shown as circles, are values more than 1.5 times the interquartile range beyond the bottom or top of the box (n = 9 replicates). c Mean ThS fluorescence signal measured from background-subtracted fluorescence microscopy images taken from 40:1 and 4:1 LCD: S2hp mixtures at 0.5 h (white) and 4 days (pink) of incubation. The experiment was performed in three biological repeats, each with technical triplicates. Five images were collected for every technical replicate. Data from all repeats were combined for the quantification. The dots are of individual data points and the bars represent mean values ± SEM (n = 45 images). Statistical significance was calculated in Prism using an unpaired two-tailed t-test with Welch’s correction. The p values are indicated with numbers and stars—****p < 0.0001. Welch’s corrected t = 5.377/ 8.597 and df = 46.59/44.33 for 40:1 and 4:1 LCD: S2hp samples, respectively. d Time-dependent shift in turbidity of LCD only (pink) and 4:1 LCD: S2hp (purple) solutions evaluated by measuring absorbance at 600 nm. Source data for panels b–d are provided as a Source Data file.