The effect of DNA concentration on expression in liposomes

DNA concentration is correlated with yield in liposomes.

A zoomed video of expression in the liposomes containing 100 ng/uL pT7-deGFP DNA.

Expression kinetics of GFP expression at each DNA concentration. Lines are generated using the liposome analysis toolkit, and represent the mean expression level of the top 1% of liposomes in the sample. We filter the top 1% as a coarse way to separate out the lower group of the bimodal distribution in each sample; we are working on ways to better categorize this group and to understand why it appears.

Correlation of top 1% liposome fluorescence to input DNA concentration. It appears that there may be two expression regimes, or a saturation effect.

Representative “fog plot” of GFP expression at 100 ng/uL input DNA concentration. Note the bimodal distribution that emerges over time.

Overview

Full-well capture of GFP expression at 100 ng/uL input DNA concentration. Note the “blinking” as expressing liposomes leak or are quenched throughout the timecourse. We are working on analyzing the statistics of this effect, to determine if it is correlated with DNA concentration or time. Warning: large video file.

Fog plots of expression at all DNA concentrations. In all samples, there is a large population of liposomes that do not increase in expression, potentially indicating a loading effect that prevents some liposomes from expressing DNA correctly.