We will develop predictive models of nucleic acid strand displacement rates to allow the rational design of complex networks of ever-increasing functionality. State of the art models mainly focus on highly-idealised systems that involve only carefully designed DNA strands at low concentrations in well-mixed solutions. In this project, we will study strand displacement technology in more complex, hybrid environments to demonstrate predictive models that can account for these more complex settings. Using molecular-level simulations, basic theory and experimental data, we will develop predictive models of strand displacement reactions in non-ideal settings, in collaboration with the other projects within BioHYBRITE. These areas include: structured environments, such as the synthetic cells; environments with competing interaction partners; and systems with hybrid RNA-DNA duplexes.