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Much more than small size, nanotechnology - a new territory

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Nanotechnology is going to take a place in our lives for decades to come. Part of this development already existed in miniaturization in microelectronics, optoelectronics, medical diagnostics, and more. And some part obtained unique features in the nano-scale systems. But the touchstone is to what extent nanotechnology will break the conceptual limits of current engineering.

 

Intuitively nano is linked to the word minimizing, to illustrate the concept of miniaturization. Let’s look at one cube made of one nanometer edge length. This cube can contain 125 atoms. One nanometer is also the size of the DNA, containing our genetic information. In DNA, the information is coded by four nucleic acids like a digital storage based on four bits of memory. that’s the reason why in Biology, the size of one bit is 1 nm.

 

So we can conclude that miniaturization is especially effective for storing information. If we take all the information gathered during mankind history (text, images, architecture, etc.), we can save all the information in 2*10^21 bits. For keeping it, we need thousands of miles of hard-disk with a base of 10 cm, however storing the information in nanometers bits, as happens in the DNA, requires the volume of a sugar cube.  The required question- is there a limit to the miniaturization where we can store information?

 

To answer this question we must look at another aspect: complexity. The hard part is not writing at small scales but how to manipulate the data at those scales. In ten nanometers thirty bases of DNA can be seen and thus can encode meaningful information, but once we pass tenth nm and reach sizes of atoms, we have no information and all the complexity is lost. Therefore nanometer is the building block for storing information, and includes some degree of complexity that allows some function. So it’s not likely that we will able to build technology based on smaller sizes than nano scale.

 

In order to understand the nanotechnology we need to understand what is happening in reducing dimensions. One of the changes is the change in geometry. If we look at a cube with a certain ratio between the volume and the surface area, when we reduce this cube, the volume is considerably get smaller compared to the surface area, so the ratio between the volume and the surface area is decreasing, meaning that in nanometer, atoms are placed on the surface area, and this is the reason why those small particles are more chemically active. In addition, the microscopic world is an isothermal one (the temperature remains the same all over the space) because the heat conductivity is greater than the heat production capacity.Nanotechnology is  mainly made in solutions which mean that particles constantly collide with each other, so they need to overcome forces of friction considerably more stronger than in the macroscopic world. We can conclude that the small dimensions bring a different expression to the laws of nature we  know in large objects, so a main part in nanotechnology is to understand how the rules of chemistry are changing.

 

One of the biggest market of chemical engineering is enzymes. Enzymes are proteins that can catalyze a certain chemical reaction. Enzyme is a complex protein, and therefore we have limited understanding of how it works. This poses a problem for us in planning new enzyme as we wish. However in order to produce a new enzyme we imitate nature by choosing an existing enzyme produced by translation of genes, and we do a process similar to evolution to get an enzymes that work effectively better and suited to the industry. We solve a difficult problem that is hard to solve with our existing knowledge by the strategy of evolution and relying on something that works without knowing how it works completely.

 

Directed evolution strategy cannot be applied to any process because evolution requires high availability of the building blocks and short production time, which did not exist, for example, in a conventional car manufacturing industry. Unlike today conventional engineering, nanotechnology  has cheap building blocks that can be mass produced in a short time.

 

Nanotechnology is more than minimized technology and even closer to biology than conventional engineering. Therefore nanotechnology is a new chapter in science we are just beginning to explore.

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