Design of a Genetic Differential Amplifier

A genetic differential amplifier is made using the control elements of genes. The output mRNA level is proportional to the difference between the concentrations of two input proteins. The active element is engineered from the right operator of bacteriophage lambda. Mutations are introduced to yield the correct gain characteristic and to provide a bias level; the latter allows for the representation of negative differences. Simulation is used to aid the design process. A test circuit has been constructed. Preliminary experimental results indicate excellent results for the inverting input and lower gain for the non-inverting input