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From 2011.igem.org

 

Safety Section

Safety Q&A | Human Practice

Background

The ideas of electronic circuit based design have long been a part of the fundamental research since the very beginning of synthetic biology. However, as the scale of designs becomes larger and larger, researchers start to find it difficult to adapt those ideas of circuits to the biological system, in which two main properties bottleneck the realization of these ideas.

First, biological reactions are considerably much slower, when compared with circuits, thus less possible to analogize the electronic components.

Second, synthetic biology fails to get the concept ‘wire’ introduced, due to the liquid environment of biological reaction, which decrease both the quality and the quantity of signals.

In this passage, we, with the consideration of the basic analysis method in information science, try to propose some new perspectives on the combination of synthetic biology and electronics.

Bottom-up Method

In modern electronics, people rarely focus on the detail of a particular component when designing systems, for these single components have already been well-characterized and standardized. All that requires is innovating rather than just repeating. When it comes to biology, we are surprised to find that some basic parts, such as AND gate, register and toggle switch, have been applied to genetic machines. While, there is still a far way to go.

1. Reaction rate

Usually, the reactions of protein expressing cost a period on the scale of hours, which is disappointing when thinking in an electronic way. Fortunately, the rate of protein-protein interaction (PPI) is relatively fast, which makes us feel optimistic. The potential of these ‘high-speed’ reactions is to be explored.

On the other side, a low rate does make a difference in some aspects, especially in those need delay. Capacitors is widely used in sequential circuits like oscillator and trigger in order to realize delay, correspondingly, the low rate in biological reaction shows its preeminence in forming delay, thus easy to establish a inertia system.

2. Independent signals

To overcome the interference of signals in liquid and simulate the function of wires in circuits, we put forward some solutions. Different populations of bacteria communicate under a variety of signal molecules, each independent with others. Whereas, it’s not as easy when the amount of signals increases, for that molecules should maintain orthogonality.

In our further research, we try to utilize microfluidical chips, which aim at separating signals and transmitting information through physical isolation, to achieve the independence of biological reactions.

Application

Oscillation can be always seen in biology, so we want to build genetic machines with an oscillation, and hope these machines are able to deal with the biorhythms. In the follow paragraph we talk about the ideas of their applications on medical treatment.

Nowadays a lot of people are suffering from insomnia, a sleeping difficulty sometimes caused by hormonal disorders. Here, we hope to use an oscillator, which can generate a signal follow the cycle of day and night. With an oscillator like this, we can build a system implanted which can cooperate with our body to regulate the hormone secretion to a proper way.

Another interesting example is about medicine taking. When catch a cold, we find it a trouble to take medicines follow the doctor’s prescription such as “taking it every 8 hours and three times a day”, sometimes we even forget it. Suppose the drug is carried in a bio-oscillator. Once we take it in, the drug inside the oscillator will be released every 8 hours automatically in our body. It will be amazing!