Fig. 1: Assessment of suboptimal, optimal, and excessive cold atmospheric plasma (CAP) doses on HaCaT keratinocytes.

a Illustration of scratch-wounded HaCaT keratinocytes plated in a 24-well plate prior to CAP exposure. b Experimental setup for CAP exposure of HaCaT cells to determine an acceptable in vitro dose definition. c Representative brightfield image (4×) of the 10 s CAP exposure group pre-treatment (0 h). d Preprocessed image from panel c with object mask placement for wound-width analysis. e Preprocessed brightfield image with object mask placement for analysis at 24 h after a 10 s CAP exposure. f HaCaT cell viability 24 h after CAP exposure for 5 s, 10 s, or 15 s (9 data points from 3 biological replicates). g Percent decrease in wound width after CAP treatment times (15 data points from 5 biological replicates). f, g Data points (black, diamond) for each exposure time, with the statistical mean (clear, squares), median (black, line in the center of box plot), interquartile ranges (box range: 25–75th percentile of data set), and outer legs of each box (lower 5th percentile and upper 95th percentile of data set) are showcased. Outliers were shown above or below the outer legs. Statistical differences between 0 s and exposure groups are identified by: ns, not significant; *p < 0.05. Exact p values can be found in supplemental data 1. One-way ANOVA with Tukey’s post-hoc test was used. Together, these formed the basis for in vitro suboptimal (5 s), optimal (10 s), and excessive (15 s) dose definition compared to no CAP exposure (0 s).