The 6 precepts for nanoscience

When someone hears the words nanoscience or nanotechnology many people think about the secret laboratories of a mad scientist controlled by governments, where robots very, very small are developed to be injected in our blood to control us from the inside. That is, the miniaturization of macroscopic structures.

Nanoscience researches the physical, chemical or biological properties of atomic, molecular or macromolecular structures, or what is the same, the structures that have a size between 1 and 100 nanometres. One nanometre is equivalent to 10-9 m or 0,000000001 m.

The study of nanoscience and the development of nanotechnology presents a lot of advantages to us such as the development of encapsulated medicines in molecules that can release its active component only where it is needed. This is the case of the treatment of patients with cancer because it could be possible to release the treatment only in the areas affected by the tumour instead of affecting other body tissues. Another example is the study of materials whose electrical conducting properties are better or even to try new methods to transmit information through materials, which, at least one of its dimensions is within the nanometric scale.

Maybe the most famous material developed in nanoscience is the graphene. In fact, Andre Geim and Konstantin Novoselov were awarded with the physics Nobel Price because of their experiments with graphene.

800px-Graphen Artistic representation of Graphene (Source: Wikimedia Commons)

To obtain materials at a nanometric scale, one of the most important ways of doing it, is to use techniques coming from the chemistry, because it can be used the properties that have atoms and molecules to bond together to create nanometric structures.

But the question here is if the miniaturization of macroscopic structures to nanometric scales can be considered as nanoscience or nanotechnology. The answer is no. In fact, not everything is nanoscience or nanotechnology and there is a set of six principles or precepts about what this emergent branch of science is.

First precept: Bottom-up building approach

This implies that miniaturizing, that is, to reduce the size of something is not nanoscience. To use the fundamental building blocks, that is atoms and molecules, and from there, to use their properties to build nanometric structures that could perform specific functions is indeed nanoscience.

Second precept: Cooperation

It does not deal with the fact that diverse institutions cooperate amongst them to develop nanostructures, which is also important, but the development of different nanostructures with different functionalities that cooperate amongst them to give rise to more complex nanodevices with better functionalities.

Third precept: Simplicity

To simplify the problems that faces the nanotechnology developments so that only the necessary scientific laws are used to avoid unnecessary complexities.

Fourth precept: Originality

Coming back to the example of the robot at the beginning of this post. It is avoided to develop things that already exist and simply reduce their size. What it is looked for are different structures. To reduce the scale has more implications than one could think, such as the fact that the volume depends on a cubic length and the area on a squared length, making a scale reduction unfeasible. Thus, it is necessary to be original and creative with the developments.

Fifth precept: Interdisciplinary nature

Previously we mentioned that the cooperation between institutions was also important, but it is even more important the cooperation between different areas of science. For this reason, the cooperation between biologists, chemists, physicists and engineers is more than needed. In nanoscience, the fact that a researcher is a pure physicist, chemist or biologists does not provide a complete knowledge because it has to face problems that will not solve unless the knowledge field is widened.

Sixth precept: Observation of nature

Nature offers us a lot of examples of nanotechnology. Molecules that make up our tissues and organs, as well as how they are organized and interact amongst them, are the best example of nanotechnology. If we observe and study them our developments will be much more innovative, efficient and will improve our lives.

It is complex to find examples that follow all these precepts simultaneously but that is why science and scientists exist, to develop nanostructures following these precepts using the laws that nature imposes.

References

The Nobel Prize in Physics 2010″. Nobelprize.org. Nobel Media AB 2014. Web. 14 Aug 2014.

El nanomundo en tus manos. Las claves de la nanociencia y la tecnología. José Ángel Martín-Gago, Carlos Briones, Elena Casero y Pedro A. Serena. Editorial Planeta S.A. Junio 2014

(Inter)stellar chemistry

When we want to know about what a material is made of, the first thing we need is, obviously, to have a certain amount of the material we want to study. Once we get it, we go to that area of the scientific knowledge, often hated by students, which is chemistry. Chemistry, as Linus Pauling defined it, is the science that study substances, its structure, its properties and the reactions that transform them in other substances.

Within chemistry, there is an area in charge of telling us what the chemical composition of the substance we want to study is:  the analytical chemistry. To achieve its objective, the analytical chemistry uses a set of methods that depending on its nature can be pure chemical methods, based on the reactions that a substance has in the presence of other ones, or physical chemistry methods, which depend on how some substances physically interact with other ones.

But, how do we do to study the chemical composition of something that we do not have any amount at hand?. This is the situation that appears, without exception, when we want to know the composition of stars or the interstellar medium. It could seem to be impossible but it is true that we know it better and better. As a proof of that, it has been recently searched for ethanethiol in the Kleinmann-Low region inside the Orion nebula.

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Kleinmann-Low region in the Orion nebula (Source: NASA APOD, CISCO, Subaru 8.3 m telescope, NAOJ)

Then, how do we do it? We need to go to different areas of science, among which we have chemistry (analytical chemistry), astrophysics and astronomy (concretely astronomical instrumentation)

We mentioned before that the analytical chemistry is in charge of studying the chemical composition and for that purpose it uses different methods. One of them is the spectrometric method, which consists in studying the interaction of the electromagnetic radiation (in every wavelength of the electromagnetic spectrum) with the matter it impacts. Spectrometry uses spectrometers (also known as spectroscopes or spectrographs) which are devices that separate de light in the wavelengths that is made of. The most simple spectroscope (in which functional principle are based all of them) is a simple prism. Using a prism, Newton managed to split the white light coming from the sun in the colors it was made of, getting in such a way the first spectrum in history. However, it was Kirchhoff and Bunsen who invented the first spectroscope by adding a graduated scale allowing them to identify the wavelength of the spectral lines observed when the light passed through the prism. When the image is registered on a device, either electronic or a simple photographic plate, we used to speak about a spectrograph.

Chemical substances can be found in the form of atoms or molecules. In the first one, individual atoms are not bounded to other atoms. In the second one, atoms, which can be of the same kind or different, are bonded amongst them through chemical bonds giving rise to molecules. The electrons that are inside atoms, or that are bond to make up a molecule, can be in different energy states. If there is not any radiation impacting on them (whatever the wavelength), electrons are in their lowest energy state. When radiation impact on them, the electrons jump to a higher energy state. However, due to the electrons tend to be in their lowest energy state, once the radiation stops impacting on them they return to their lowest energy state and, for it, they have to get rid of the energy excess provided by the incoming radiation, emitting the excess of energy in the form of radiation. The difference between the energy of the initial and final energy states tells us the wavelength of the emitted radiation.

Each atom or molecule has different energy states that are characteristic and, therefore, depending on the incoming energy, the transitions between energy states will be different and thus the emitted radiation will be different too. These energy states can be of different types and include vibrational states (due to the vibration of the atom or molecule) or rotational states (due to the rotation of the atom or molecule). On another hand, each energy state cannot be a single one, but can be split in different states in presence of, for instance, a magnetic field, thus enabling additional transitions and the possibility of the emission of the excess of energy in additional wavelengths.

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Transitions between energy states that give rise to spectra (Source: monografías.com)

Analytical chemists use, amongst other methods, the spectrometric method to study the structure of these atoms or molecules and their interaction with radiation. Because each atom and molecule has a specific structure of energy levels different to the rest, and that it interacts with radiation in a specific way depending on the type of radiation (and the environmental conditions, such as the presence of magnetic fields), it can be created a catalogue of spectra, so that the next time we see the same spectrum in other place, we could identify the substance we are dealing with.

Some of the places where we can find spectra are stars and the interstellar medium. The problem we have is that we cannot directly access to the star, gather some amount of matter and take it back the laboratory to study it. What we can do is to use our optical telescopes or radio telescopes, to equip them with spectrographs to give us the chance to observe the spectra, with sensors appropriate for the type of radiation (wavelength) we want to observe and point them towards the region of the sky we want to study. The analysis of the spectra through its comparison with the spectra obtained in the laboratory could give us the chemical composition of our object under study. And not only that, we are going to be able to get much more information such as the rotation and translation speeds that have the object (through the measure of the Doppler effect, because the spectral lines will appear displaced, with regards to its position in the laboratory, to the spectrum part where there are longer or shorter wavelengths depending on whether the object is approaching to or recessing from us) or even the intensity of the magnetic field that could be in the region we are looking at.

As always, reality is always much more complex, but we can always rely on the human will and the capacity that scientists have to look for solutions to the problems that the universe presents. And as it has been seen, what for me is the most important thing, we can rely on the collaboration between different scientific areas in the search for those solutions, appearing, in some cases, new scientific fields as result of such collaboration. This is the case of Astrochemistry, which is basically the scientific area that has been addressed in this post.

References:

http://www.espectrometria.com/