Overview

Why E.calculus ?

During our brainstorming meetings to define our iGEM project, we realized that various arithmetic operations were present in many cellular systems, like intracellular regulations and controls, or even in the control of metabolic pathways. We therefore decided to create a n-bit bacterial full adder which could be operated by the user, and able to transmit a carry if needed. Considering that some of the previous iGEM projects tackled the bacterial adder concept, and using new systems of logic recombinatorial gates, we aimed to create a robust and strong device in a bacterial chassis. We also wanted to demonstrate that recombination-based gates represent a quite simple yet efficient way to build genetic logic gates that could be used further to design pure genetic devices.

From TI83+ to E.calculus

An electronic full-adder consists of the association of 5 logic gates (2 XOR gates, 2 AND gates, and 1 OR gate) which are able to receive 3 input signals (2 input bits and the last stage carry) and give the right answer to the user. (View "Full Adder" Part)

With E.calculus, we also tried to transpose this electronic device into a genetic device (system) based on recombination principle. We chose to use blue and red light as bit inputs (View "Input" Part), and a diffusive molecule for the carry (View "Carry" Part) . The answer should be readable by the manipulators, that is why we chose to use a red pigment (View "Output" Part), visible by human eyes at a low concentration.