This blog post introduces the latest biotechnology that uses genetic engineering and viruses to create nanoelectronic devices.
Based on genetic information recorded in their own DNA, living cells produce proteins, which are the most sophisticated and complex molecular structures discovered by humankind to date. Proteins are key elements that perform various life activities within cells and can be considered the structural and functional building blocks essential for life. Protein synthesis is not limited to functions necessary for survival. Based on the precision and efficiency of this mechanism, scientists are now attempting to convert the activities of living organisms into technology.
Today’s science and technology has reached the level of decoding and manipulating genetic information. In particular, the genetic information of microorganisms is relatively simple and easy to manipulate, making it a stage for various research and application experiments.
In the past, life and engineering were considered completely different fields, but recent studies have shown that the principles of life, especially the genetic mechanisms that synthesize proteins, can be used to create electronic devices such as semiconductors and transistors. One of the most notable examples is an experiment conducted by a research team at a university in the United States to create electronic devices using bacteriophages.
Bacteriophages are a type of virus that infect bacteria, measuring approximately 7 nanometers (nm) wide and 800 nm long, with a rocket-like structure. The research team selected viruses with the property of strongly attaching to semiconductor materials from among numerous bacteriophages through a process of repeated induced evolution.
When a precursor substance containing a semiconductor material is introduced into these viruses, a dot-shaped semiconductor crystal, or quantum dot, with a diameter of 2 to 3 nm is formed by a short protein called a peptide that makes up the tail. These dots are ultra-fine structures that are difficult to create using conventional chemical processes and are the result of the precise self-assembly capabilities of living organisms.
The research does not stop there. The research team decoded the genetic information for synthesizing peptides from the DNA of bacteriophages and successfully replaced this genetic information with the genes that make up the proteins that constitute the virus body. As a result, a new type of virus was created, in which not only the tail but the entire body is made of peptides, i.e., a virus variant with a conductive peptide outer membrane.
When a precursor substance is reintroduced into this virus, a semiconductor crystal film forms along the outer membrane of the peptide-based body. When this structure is heated to a high temperature and the virus body is burned, the organic material disappears, leaving only the semiconductor crystal film. This process creates nanowires with a diameter of about 10 nm, which are important components for conducting electricity in electronic devices.
The research team expects that conductive viruses with peptide-based outer shells, or wire viruses, will be mass-produced in the near future. This means that ultra-fine devices can be realized with much lower energy and costs than existing semiconductor manufacturing processes, and is considered a revolutionary technology that could change the landscape of electronics.
However, in order to utilize these wire viruses in the actual production of semiconductor devices, it is essential to develop technology that controls them so that they attach precisely to the desired location. To this end, the research team once again applied guided evolution and genetic engineering to genetically modify the head and tail of the wire virus so that they would adhere well to gold electrodes.
When the modified viruses are applied to a substrate (wafer) with two gold electrodes placed at a distance corresponding to the distance between the head and tail, the two ends of the viruses attach to the two electrodes. In this state, a semiconductor material is formed on the virus body as described above, and after high-temperature combustion, an ultra-fine semiconductor nanobridge connecting the two electrodes is created. This structure can perform functions beyond simple connection.
If another control electrode is inserted inside the insulating layer between the two electrodes, the entire structure functions as a complete field effect transistor (FET) with a 10 nm wide conduction channel.
In this way, the use of bacteriophages enables the biological fabrication of basic unit devices for the realization of very large scale integration (VLSI), which is one of the ultimate goals of semiconductor technology. Crystals made using viruses are much more homogeneous and precise than structures made with current semiconductor manufacturing technology. Experiments have proven that biological self-assembly is much more efficient and accurate than conventional machine-based lithography and chemical processes. For this reason, device manufacturing methods using various microorganisms such as bacteria, viruses, and fungi are being actively researched in the field of nanoelectronic devices, and interest in this area continues to grow. The ultimate goal of this research is to realize an autonomous system in which genetically programmed organisms can create complete electronic devices without human intervention.
Scientists describe this as a kind of “biochemical dance.” This process, in which genetic information provides the rhythm and proteins assemble precise molecular structures in accordance with that rhythm, is reminiscent of a sophisticated performance in which life and technology come together in harmony.
Of course, current technology is based on viruses that can only multiply inside bacteria, such as bacteriophages, so there are certain limitations to achieving this biochemical harmony. However, living cells are much more complex than viruses and can perform multiple tasks simultaneously. Cells are sensitive to environmental changes and have the ability to regulate various responses in real time, even under complex conditions.
For this reason, scientists are increasingly turning their attention to the use of living cells in the manufacture of nanodevices. Cells can be used to go beyond the manufacture of simple electronic devices to form complex structures and even perform functions such as self-diagnosis and self-repair of damaged devices. This is one of the possibilities offered by biological self-healing and advanced convergence technologies, which are difficult to achieve with existing technologies.
Ultimately, the precise and stable mechanisms that living organisms have developed over billions of years of evolution are now leading to new forms of innovation through convergence with science and technology. This “mechanism of life,” in which genes provide the blueprint and proteins assemble it, is now creating a new future on the stage of electronics. We are now in an era where cutting-edge processes for electronic devices are being created with the help of living organisms. We may be standing at a marvelous turning point where the boundaries between technology and life are collapsing.
