The flippant answer to the question would be that Synthetic Biology is man-made biological substances and systems. That simple answer does not do the question justice. Synthetic biology is a multidisciplinary process that draws upon many different areas. These include evolutionary biology, biotechnology, genetic engineering, molecular engineering system biology, biophysics, biological engineering, chemical engineering, electrical engineering, computational engineering, control engineering, and many other fields. Synthetic biology aims to create new biological parts, devices, and systems or to redesign natural systems.
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The history of synthetic biology goes back to 1828 when Friedrich Wohler produced Urea, a substance produced by animals to remove waste in urine, by reacting ammonium chloride with silver isocyanate. The product was an organic naturally occurring molecule produced with inorganic chemistry. The term Synthetic Bilogy was coined by Stephan Leduc in 1910 in his book Théorie Physico-chimique de la Vie et Générations Spontanées. But Science has made vast strides in the late 20th and early 21st centuries. In 2019 ETH Zurich reported they had produced the first bacterial genome created by computer. Now completely artificial or “synthetic” life forms are possible.
Synthetic biology often works closely with Systems biology. Systems Biology is the study of natural biological systems, whereas Synthetic Biology seeks to build new artificial biological systems.
Engineering and Synthetic Biology
The Royal Academy of Engineering, in a 2009 paper, stated, “Synthetic Biology aims to design and engineer biologically based parts, novel devices, and systems as well as redesigning existing natural biological systems.” These outcomes can be achieved by collaboration between engineers, biologists, chemists, physicists, and social scientists and philosophers. To the Academy, the critical feature of synthetic biology is a rigorous application of engineering principles to biological systems and following the engineering process of specification, design, modeling, testing, and validation.
Engineers regard biology as a technology. The goal is to design and build engineered live biological systems to process information, manipulate chemicals, manufacture materials, and structures, produce food and energy and enhance human health. The possibilities are staggering.
Synthetic Biology is making huge strides as we learn more about cells using modern technologies to observe their functions and components. These technologies allow us to know more about biological processes such as biochemical pathways, metabolic reactions, gene control, cell division, and intercellular communication.
We can also observe and identify and observe macrocellular components like proteins, sugars, nucleic acids, and proteins. Once the components have been identified, their function can be determined. Once determined, the functions can either be used or altered to give the effect required.
The most important substances are DNA and RNA. Modern technology and computational modeling have allowed DNA and RNA components to be identified and sequenced. These technologies mean that DNA, one of the main building blocks in Synthetic Biology, can be synthesized. The CRISPR (clustered regular interspersed short palindrome repeats) system has made it relatively fast and straightforward to sequence DNA.
Nucleotides can be identified and sequenced into a new DNA. Modular nucleotides are the building blocks of DNA sequencing, and blocks known as Biobricks are available from a database, the Registry of Standard Biological Parts at Massachusetts Institute Of Technology. The code can be purchased for relatively small sums of money and used to build new DNA sequences.
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Living biological systems have benefits for engineers. They can self-organize using non-covalent bonds, which can easily be broken and remade. They can also deal with “noise” and retain order despite many random happenings occurring within the system. There is often a feedback loop in biological systems that is useful for engineering.
Over three thousand signaling proteins and fifty secondary messenger chemicals have been identified to date. Components are identified by Systems Biology and added to an inventory, which Synthetic Biology then uses to build into systems. Bio parts have much broader tolerances than traditionally engineered parts.
DNA can be used as a component or a machine in its own right. Synthesized DNA structures can be used to create living computers with the capability of digital or analog computation. Equally, it can be used to help produce specific compounds. DNA can be used on its own or to substitute into existing cells to modify how they function. This method has many applications.
Sometimes to achieve specific outcomes, a so-called “chassis” is used. In this process, a bacterium such as E Coli has its DNA removed and replaced with purpose-built DNA. These modified cells can then carry out medical functions, such as killing cancer cells or delivering drugs to cancer tumors. They could also be used for bioremediation in the environment to specific contaminants such as PFAS (polyflouroalcohols), which are persistent and do not break down in the natural environment.
Modified bacteria can also be used as biosensors in medicine or environmental monitoring. They can be modified to produce fluorescence in the presence of particular compounds or pathogens, which be detected or measured electronically.
Modified bacteria have potential in the production of biofuels where traditional processes using palm oil or sugar cane can waste up to 90% of the biomass produced. Using synthetic bacteria to produce ethanol could eliminate plant waste.
It is fair to say that the possibilities of Synthetic Biology are almost limitless. This lack of limits creates a moral and ethical dilemma. The vast majority of Synthetic Biologists are using the technology for good, but it is always possible for technologies to be hijacked for malintent.
For example, it could be possible to create a virus from scratch with printed circuits built into its protein. Equally, it could be possible to produce a pathogenic virus. Synthetic biology development and application require appropriate regulation, but most legislators will not understand its implications or possibilities.