Whereas high throughput pipetting robots can perform chemical mixing and sampling operations efficiently, transforming chemical mixtures from one reacted state to another, they are less useful in handling spatially structured, multilevel or ongoing reactive processes or even timed sequences of reactions. Chemical microprocessors provide dynamic soft-walled microchemistry, replacing passive test tubes or microwells by active dynamically controlled and even self-assembling microcontainers. Such electronically programmable microcontainers for chemical reactions do more than allow the user to integrate pipetting operations in parallel and in picoliter volumes. Electronic aggregates, formed directly by electric fields or by the novel technique of electronic phase control (triggering mobility phase transitions as described above), not only allow the user to locally encapsulate, transport, sort and release chemicals in discrete quanta inside microfluidic devices.
More importantly, and as a unique advantage, chemical microprocessors through their microscopic local feedback and real-time parallel control of each local chemical process and the ability to take advantage of and preserve spatial and phase structures produced by reactions, allow the electronic program to individually and continuously monitor, modulate and regulate each complex process. This opens the door to evolutionary optimization of the information controlling each local process. Different processes can be brought into contact in process flow networks to build complex integrated systems. In typical chemical microprocessor applications, information will be gained from complex processes, they will be optimized and combined and some of these complex processes can be soft-packaged and exported intact from the device. This evolvable chemical integration, taking advantage of a full range of locally applicable separation, concentration, media exchange and purification processes, makes chemical microprocessors the method of choice for integrated programmable chemistry. It is a feature not shared by other biochip or microfluidic technologies such as the Nanogen or Caliper.
Thus chemical microprocessors go beyond conventional lab-on-a-chip technology, but we can also outline their advantage in this more famliar market, where the explosion of both the number of different chemicals and the complexity of biochemical systems requiring deployment testing, as a result of the various –omics fields from genomics and proteomics to metabolomics, has posed increasing pressure on the biotech industry towards providing increasingly custom solutions in high throughput. Currently, the setup time for establishing novel biochemical assays in each lab limits the complexity and throughput of applications in biotechnology. Specific lab-on-a-chip integrations, while improving reproducibility, do not shorten development time for novel applications. The increased versatility of chemical microprocessors, stemming from their reconfigurable architecture and cell-like process-scale electronic control, can also be harnessed to reduce development time, and increase reproducibility and transfer achievements and protocols from one context to another in these areas.
Only with a truly programmable digital technology for multilevel chemical manipulations, as provided by chemical microprocessors, will it be possible to build-up and communicate successively more complex chemical algorithms.
Summary: Why use chemical microprocessors?
- the novel open-ended technology linking chemistry with IT,
- the ability to reliably integrate chemistry towards cellular complexity including spatial and multilevel self-assembling processes
- the ability to optimize and evolve chemical systems incrementally under digital control, and to increase the sophistication of local control
- the one time investment in a generally programmable platform with high reproducibility and rapid development time for a wide range of application variants,
- the ability to build up, link, evolve, store and communicate libraries of reproducible protocols
