A block diagram describing the basic components and functions of the omega machine is shown opposite. The diagram below highlight the essential online monitoring-control feedback loops at the level of single cells describing omega machine components and functionality. The machine incorporates reconfigurable electronics together with interface electrodes to implement combinatorially programmable actuator networks. It incorporates a 3D microscopy interface, which takes advantage of high-bandwidth CCD computer interfaces and sensitive detection with laser induced parallel (optionally confocal) fluorescence to provide parallel monitoring of thousands of potential artificial cell sites in 2D or 3D. The microfluidics system processes chemicals from external reservoirs and outputs products (either molecular concentrations or transportable mesoscale structures such as vesicles with specific content, up to complete artificial cells). The delivery and product selection is made reconfigurable (and thus combinatorially optimizable) through electrode arrangements, which impinge on the fluid. The result is a functional feedback loop integrating local self-organization with information processing and evolution. The functionality of candidate protocells is evaluated and more successful variants selected (spatially in situ through electronic control), the system is then reconfigured to allow new variant protocells to be formed at inferior locations under modified support.
Although the generic omega machine as described above has already been designed and built in our lab, the functionality is still in its infancy en route to artificial cells. One can identify eight potential development phases in the functionality of microfluidic systems towards a full omega machine for artificial cells:
- 1) Single phase localized replication: with self-replication confined to a localized region by restraining fields and flows
- 2) Dual phase dynamic containers: making use of phase boundaries (such as membranes or interfaces between hydrocarbons and water) for containment. The two phase containers should be able to be formed locally from raw material flows within the microfluidic system, and be transported within the system. Container self-reproduction may involve container growth and division or more simply transfer of old container contents to two newly formed containers.
- 3) Regulated chemical self-replication: with the omega machine providing gain-control: the equivalent of the Q-factor for laser operation or neutron decelerating material for nuclear chain reactions. The localized regulated replication centers can then deliver replicated genetic material on demand to form to the microfluidic transfer system to form new replication centers
- 4) A combinatorial niche search machine : capable of generating (under programmable control) a combinatorial repertoire of niches (building on the gradient reactors) to allow joint combinatorial search of molecular libraries and local control patterns. This should be used to search both for genetic molecules with catalytic functionality (e.g. modification of precursors to active building blocks) and collective amphiphilic properties.
- 5) The integration and co-evolution of self-replication and metabolic catalysis
- 6) The integration and co-evolution of container components and self-replication
- 7) The omega machine supported cell, integrating metabolism, self-replication and containment
- 8) Evolutionary transfer of functions from the machine to the artificial cell.