Optical Simulations in Life-Sciences: Benefiting from Ray-Tracing in Biotechnology and Photobiology

The advent of LED technology opened up new possibilities for the implementation of versatile and complex illumination systems for photobiological and biophotonic studies. However, these new lighting systems also increase the requirement for accurate and reproducible characterization of existing light parameters such as irradiance or photon flux density. A direct determination with radiometer or quantum-meter is not always possible due to complex experimental setups. Optical simulations based on ray-tracing software can compensate the limitation of direct measurements and make more information regarding light quantities available. In this paper, we provide a guideline to modeling life-science experiments using ray-tracing software and demonstrate the potential of optical simulations by addressing specific scientific questions. In detail, we discuss irradiance distribution in UV inactivation studies and the determination of photon flux density in light-stress experiments with microalgae using ray-tracing software and comparing simulation results with optical measurements. Furthermore, we demonstrate the possibility to improve existing irradiation conditions by common optical engineering optimization techniques. This will be shown by means of a photobioreactor illumination as well as an application in the field of photodynamic therapy. Our simulation results were in good agreement with direct measurements and allowed us to gain additional information regarding light quantities that could not be measured directly.