Introduction

Why?

Hockberger et al (1999) suggest that blue light up to 470 nm can have some phototoxic effect on mammalian cells, from 2 to 6 J/cm². In our experiments, we have observed a much higher cell death rate in the cultures exposed for 24h to blue light than in the control. 24h at 20 mW/m² is actually more than 1700 J/cm². To stay on the safe side, and give the cells 6 J/cm² during 4 hours would mean an average of 0.4 mW/cm².

• How much activation can we get with this rate?
• Will we have to push it up?
• What lighting pattern will give best results?

To optimize the number of experiments to perform, we have built a simple model to predict the proportion of photoproduct to be expected at every time point when a sample with LovTAP-VP16 when it's illuminated with a time varying light input.