Recently, biological engineers led by Drew Endy at Stanford University have made that final breakthrough, developing a “transistor” (that they have named transcriptor) made of DNA and RNA that is capable of acting as logic gates, such as AND and XOR (shown in Fig. 1) . Now with all three components in place, further proof of concept and initial research should start to emerge, paving the way for many future possibilities.
Breaking Down the Components
When researchers started to look at a way to replicate this in living systems, they ran into a fortunate coincidence, such a storage method already existed, utilizing deoxyribonucleic acid (DNA), ribonucleic acid (RNA), and various other proteins. These elements are combined into sequences that are later read and used by ribosomes to produce a certain type of protein that the cell needs. Scientists have figured out ways to produce their own strands of DNA encoded in a way that translates into something like an image or a word.
Using DNA as a storage method not only works, but presents many benefits as well. DNA storage is very dense, supporting EXAbytes (〖10〗^6 terabytes!) per gram of single stranded DNA , is already used by life which allows for easy exchange between the cellular computers and the organism, and lasts over a millennia even in non-ideal states .
Using a very specific type of printer, DNA designers can produce DNA strands in a strand that represents a sequence of information . This can be then “uploaded” to the cell that contains our cellular computer. Or if the device itself is producing the information, then it can write the data to strands of DNA directly  that later we can access.
Processing a basic system of logic
Dr. Endy and a team of researchers have found a way to employ these logic operators with cellular modules built from plasmids and integrases . These modules contain Boolean integrase logic gates( BIL gates), that are capable of applying tests of logic. These gates can be further configured through control signals that switch the parameters of their test. This breakthrough acts in way similar to transistors, which is why these particular modules are termed “transcriptors”, a combination of transistor and scripting, as in re-scripting DNA sequences by releasing enzymes depending on the output value. You can see an example of this in Fig. 1.
At the very simplest end of the spectrum of opportunities that this technology affords is simple counting tasks. This alone is stunning. Having current information from your body, or an animals’ or plants’, allows doctors/ veterinarians/ botanists to make educated, informed decisions based on instant data, which allows them to catch or prevent many diseases before they start. Using a transcriptor utilizing an AND operator could register True values if two certain proteins are present that are associated with a particular disease . A doctor can be alerted by these computers that you’re starting to have abnormal levels of these two proteins and he can make steps to remedy the situation. Of course, you can eliminate the doctor from the equation altogether by allowing the information gathered from the AND transcriptor to be transmitted to another transcriptor via the M13 virus, and that transcriptor can tell a cell to produce chemicals to counteract the rise in harmful protein levels.
Or you might install these computers in a plant to not only react to harmful chemicals by turning blue, but to a variety of environmental conditions and respond by altering the plant to be able to thrive in that environment, for example, being able to repel insects or producing an extra layer of foliage to insulate itself from extreme cold.
-  Sebastein Anthony (March 29, 2013). “Stanford creates biological transistors, the final step towards computers inside living cells”. Extreme Tech.
-  Gautam Naik. (2013, Jan 24). Storing Digital Data in DNA [Online]. Available: http://online.wsj.com/article/SB10001424127887324539304578259883507543150.html
-  Monica E Ortiz, Drew Endy, “Engineered cell-cell communication via DNA
- messaging,” Journal of Biological Engineering 2012, 6:16
-  Jerome Bonnet, Peter Yin*, Monica E. Ortiz, Pakpoom Subsoontorn, Drew Endy, “Amplifying Genetic Logic Gates,” Department of Bioengineering. Stanford Univ., Stanford,Ca. Rep. 10.1126/science.1232758, 2013
-  George M. Church, Yuan Gao, Sriram Kosuri , “Next-Generation Digital Information
- Storage in DNA,” U.S. Office of Naval Research 10.1126/science.1226355, 2012
-  Emily M. LeProust, Bill J. Peck,Konstantin Spirin, Heather Brummel McCuen, “Synthesis of high-quality libraries of long (150mer) oligonucleotides by a novel depurination controlled process,” 2010 March 20. doi: 10.1093/nar/gkq163
-  Devin Burill, Pamela Silver ,“Making Cellular Memories” 10.1016/j.cell.2009.12.034 Cell, Volume 140, Issue 1, 13-18, 8 January 2010
-  Yaakov Benenson, “Biomolecular computing systems: principles, progress and potential”, (July 2012) doi:10.1038/nrg3197