Computation of Ratios Using Chemical Reactions and DNA Strand Displacements

Recent researches has focused on nucleic acids as a substrate for designing biomolecular circuits for in situ monitoring and control. A common approach is to express them by a set of idealised abstract chemical reaction networks (ACRNs). Here, we present new results on how abstract chemical reactions, viz., catalysis, annihilation and degradation, can be used to implement circuits that accurately compute ratio of two input signals. The input signals can be either constant-valued scalars or time-varying scalars or polynomials. We also characterise the robustness of our circuits to parameter variations, as would be encountered in wet-lab implementations.