Microfluidic-electronic devices allow multi-electrode structures at the same scale as cells, so that individual control of emergent spatial structures is achievable. Our electronic chemical cells will exploit electronic chips as coprocessors and memories for genetic information.
- Firstly, local molecular concentrations can be changed by digital voltages (1-5 V) that induce directed transport (electrophoresis and electroosmosis), guiding molecular self-assembly and inducing phase transitions and hence controlling the mobility, separation and transport of molecules. scpDNA will autonomously contribute to selective containment of different polyelectrolytes by supporting reversible hydrogel structures inside MEMS channels.
- Secondly, electrochemical control (via electrodes) of key redox reactions for chemical synthesis will provide a direct microscopic local control of the energy flow and reactions in the electronic cell. Redox reactions provide a universal currency for regulating chemistry coupled to an external energy source: hence this opens the door to synthetic programmability.
- Thirdly, electronic control of replication and self-reproduction will be achieved by combining these effects.
While it would be possible to use electric fields both as actuators and sensors, and this is the ultimate intention, the parallelization of direct electronic sensing is still limited because of signal amplification sensitivity and cross talk, so that this proposal utilizes rapid fluorescence imaging of chemical reactions (with sensitivity down to single molecule levels) for sensory feedback to the electronic system. Mean-while, this optical sensory system gives us reliable diagnostic tools and supports a range of subsidiary applications to analytical biotechnology. ECCells depend on external energy for their operation, in the form of chemical building blocks and electrical power, but they must self-organize to be able to make use of this energy for their construction and operation. In principle, ECCells could eventually be used to close the design loop and evolve intelligent solar energy cells that adapt their properties to local environmental, but this is outside the scope of the current project.
Redox processes coupled electrochemically to microelectrode operation allow a rather general chemical energy currency to be employed which can be coupled to drive a huge range of potential reactions. Similarly, the complex ion gradients created by electric fields provide a universal motor for directing chemical reactions : both simple pH gradients but also charged informational molecule gradients play a role here. Incidentally, natural cells employ both proton gradients and redox chemistry to couple many processes to their energy sources. The ECCell electronic activation thus can support adaptive changes in the synthetic chemical reactions being performed and is thus worthy of the title of a metabolism.
