BIONANOTECHNOLOGY: History, features, methods adopted, instruments used, criteria to use the instruments & applications.

Biotechnology has grown, and is still growing, with each new discovery in molecular biology. Further research into viral biology has led to improved vectors for delivering new genetic material. An explosion of enzymes for clipping, editing, ligating, and copying DNA, as well as efficient techniques for the chemical synthesis of DNA, has allowed the creation of complicated new genetic constructs. Engineered bacteria now create large quantities of natural proteins for medicinal use, mutated proteins for research, hybrid chimeric proteins for specialized applications, and entirely new proteins, if a researcher is bold enough to design a protein from scratch.

FROM BIOTECHNOLOGY TO BIONANOTECHNOLOGY

We are now poised to extend biotechnology into bionanotechnology. What is bionanotechnology, and how is it different from biotechnology? The two terms currently share an overlapped field of topics. I will define bionanotechnology here as applications that require human design and construction at the nanoscale level and will label projects as biotechnology when nanoscale understanding and design are not necessary. Biotechnology grew from the use of natural enzymes to manipulate the genetic code, which was then used to modify entire organisms. The atomic details were not really important existing functionalities were combined to achieve the end goal. Today, we have the ability to work at a much finer level with a more detailed level of understanding and control. We have the tools to create biological machines atom-by-atom according to our own plans. Now, we must flex our imagination and venture into the unknown.

Bionanotechnology has many different faces, but all share a central concept: the ability to design molecular machinery to atomic specifications. Today, individual bionanomachines are being designed and created to perform specific nanoscale tasks, such as the targeting of a cancer cell or the solution of a simple computational task. Many are toy problems, designed to test our understanding and control of these tiny machines. As bionanotechnology matures, we will redesign the biomolecular machinery of the cell to perform large-scale tasks for human health and technology. Macroscopic structures will be built to atomic precision with existing biomolecular assemblers or by using biological models for assembly. Looking to cells, we can find atomically precise molecule-sized motors, girders, random-access memory, sensors, and a host of other useful mechanisms, all ready to be harnessed by bionanotechnology. And the technology for designing and constructing these machines in bulk scale is well worked out and ready for application today.

Nanomedicine will be the biggest winner. Bionanomachines work best in the environment of a living cell and so are tailored for medical applications. Complex molecules that seek out diseased or cancerous cells are already a reality. Sensors for diagnosing diseased states are under development. Replacement therapy, with custom-constructed molecules, is used today to treat diabetes and growth hormone deficiencies, with many other applications on the horizon. Biomaterials are another major application of bionanotechnology. We already use biomaterials extensively. Look around the room and notice how much wood is used to build your shelter and furnishing and how much cotton, wool, and other natural fibers are used in your clothing and books. Biomaterials address our growing ecological sensitivity—biomaterials are strong but biodegradable. Biomaterials also integrate perfectly with living tissue, so they are ideal for medical applications. The production of hybrid machines, part biological and part inorganic, is another active area of research in bionanotechnology that promises to yield great fruits. Bionanomachines, such as light sensors or antibodies, are readily combined with silicon devices created by microlithography. These hybrids provide a link between the nanoscale world of bionanomachines and the macroscale world of computers, allowing direct sensing and control of nanoscale events.

Finally, Drexler and others have seen biological molecules as an avenue to reach their own goal of mechanosynthesis using nanorobots. Certainly, biology provides the tools for building objects one atom at a time. Perhaps as our understanding grows, bionanomachines will be coaxed into building objects that are completely foreign to the biological blueprint.

This article explores these bionanomachines:
their properties, their design principles, and the way they have been harnessed for our own applications. An exponentially growing body of information is being amassed, revealing the structure and function of individual biomolecules and their interactions within living cells. This information is a key resource for understanding the basic principles of nanomachinery: its structure, its function, and its integration into any larger application of nanotechnology. These existing, working nanomachines provide important lessons for the construction of our own nanotechnology, whether based directly on biology or constructed completely from our own imagination.

WHAT IS BIONANOTECHNOLOGY...?

Nanotechnology and bionanotechnology are entirely new concepts, invented late in the twentieth century, and biotechnology has only been around for a few decades, so the scope of these fields is still being defined. With so many clever researchers working on all aspects of nanoscale structure, construction, and function, new examples that cross existing conceptual boundaries are appearing daily. Before getting started, it is worth spending a moment to compare the many technologies working at small scales and try to define the current scope of bionanotechnology. 

Chemistry was the first science to manipulate molecules, starting when the first human beings cooked their food. Today, chemists design molecules and perform extensive, controlled syntheses to create them. Chemistry differs from bionanotechnology because it does not work at the level of individual molecules. There is no localization at the atomic level and no ability to address individual molecules. As a consequence of the bulk nature of chemistry, the molecules produced are generally limited to under a hundred atoms or so syntheses of larger molecules are plagued by too many side reactions that form competing impurities. 

Photolithography is widely used for the creation of computer hardware, and the growing field of MEMS is applying these technologies to the creation of microscale machines. Our entire information and communication technology relies on these methods. It relies on photographic techniques for reduction of scale and random deposition of atoms within the mask. Thus it is a macroscale technique scaled down to its finest limits. 

Biotechnology harnesses biological processes and uses them for our own applications. In this book, I will limit the scope of biotechnology to applications that do not require atomic specification of biomolecules. For instance, researchers routinely use purified enzymes to cut and paste genetic instructions and add these back into cells. Knowledge of the atomic details are unimportant, just as knowledge of the type of ink used to print this page is not important for understanding of the words printed here. 

Nanotechnology has been defined as engineering and manufacturing at nanometer scales, with atomic precision. The theoretical constructions popularized by K. Eric Drexler and the Foresight Institute are perhaps the most visible examples, and these are often further classified as “molecular nanotechnology.” The positioning of individual argon atoms on a crystal surface by researchers at IBM is a successful example of nanotechnology. 

Bionanotechnology is a subset of nanotechnology: atom-level engineering and manufacturing using biological precedents for guidance. It is also closely married to biotechnology but adds the ability to design and modify the atomic-level details of the objects created. Bionanomachines are designed to atomic specifications, they perform a well-defined three-dimensional molecular task, and, in the best applications, they contain mechanisms for individual control embedded in their structure.

How big is bionanotechnology? Since the Industrial Revolution, scientists and engineers have constructed machines at an ever-smaller scale. Machines in our familiar world have moving parts in the range of millimeters to meters. As machining capabilities improved, tiny machines, such as the movement of a fine watch, extended the precision of machining to a fraction of a millimeter. Computer technology, with its ever-present pressure to miniaturize in order to improve performance, has driven the construction of tiny structures to even smaller ranges, with micrometer-scale construction of electronic components and tiny machines, like these tiny gears, created at the Sandia National Laboratories. Bionanotechnology operates at the smallest level, with machines in the range of 10 nm in dimension. The bacterium shown builds thousands of different bionanomachines, including a working nanoscale assembler, the ribosome, shown at lower right. Because these bionanomachines are composed of a finite, defined number of atoms, they represent a limit to the possible miniaturization of machinery