Life and Nanoscience

About as long as there has been intelligent human life (or maybe even longer when one considers the possibilities of various other intelligent life forms), a set of fundamental questions have been posed lacking full answers regarding our existence. As described in my last post, the continuation from the principles of physics to chemistry to biology has offered these questions regarding how this process has come about in such an elegant manner: how could the Universe have possibly gone from the excess of matter particles to atoms to molecules to life forms? While we have not solved these puzzles yet, many steps have been made in the direction of answers.

My current research in Germany has opened my eyes to many interesting aspects in answering such questions. I’m not here to propose a concrete answer, but rather to facilitate a similar curiosity in how such seemingly complex systems could arise from the simple building blocks. This concept is central to the work done in nanotechnology, which is the field I am currently exploring here in Munich—a field that offers various interesting applications within my academic realm of biomedical engineering. I will begin with a bit about the fundamentals of my research for those of you back home that would like to know what I’ve been spending time doing here, and to set the stage for the concepts that relate back to the most crucial questions of the Universe.

I am currently involved in research with Dr. Lackinger in a Nanotechnology Lab concerned primarily with the characteristics of 2-dimensional surface-supported self-assembly of supramolecular aggregates at the solid-liquid interface, often resulting in nanoporous, monolayer crystalline networks depending on various environmental conditions (yes, I strung all that together just for fun). What does this mean in non-scientific terms? We look at how molecules can form certain patterned networks on top of a surface. And how do we see these molecules? I, specifically, use an instrument called an STM (Scanning Tunneling Microscope).

STM-imaging is based on a principle of quantum physics called quantum tunneling, where a particle—in this case, namely an electron—tunnels through a potential barrier in a way that classical physics would not allow. I will use a typical example for sake of convenience; in classical mechanics, a ball would not be able to reach the top of a hill and get to the other side without the necessary amount of energy, but the quantum tunneling effect describes the phenomenon in which a particle at an energy below that of the barrier tunnels through to the other side. In the case of the imaging system, we get our image because of electrons that tunnel between the atoms of a conducting or semi-conducting surface and atoms at the tip of a sharp metal probe about 1 nanometer from the surface—an electronic circuit made possible by electron tunneling. We get a tunneling current by applying a bias voltage to the tip, and since the probability of quantum tunneling decreases exponentially with distance, we use piezocrystals to constantly reposition the tip such that a constant current is maintained; therefore, the tip maps the electronic structure as it is scanned across the surface.

We use this STM then to visualize how molecules may assemble themselves on a surface (I use graphite surfaces). The interesting point I want to share with you, and the point that brings us back to the original discussion, is that this process of network assembly happens spontaneously. The blueprint for this structure is held in the characteristics of the building blocks themselves. The rules of the interactions decide how the structure will come together. In my research, these interactions are largely governed by hydrogen bonding of the molecules’ functional groups and Van der Waals interactions with the surface, all subject to the minimization of Gibbs free energy. So, when the rules allow it, a more complex entity can result from the building blocks.

What then distinguishes formation of life from this process, or from the process of particles forming atoms in the early Universe? One of the unique characteristic of life is the process of reproduction, and some form of information-carrying needs to exist to facilitate that reproduction. The world today holds many complex biological beings that have DNA to carry information, but was this always the case for life forms?  At the moment, there are a multitude of viable theories set to explain how the transition may have happened: some say genes first, some say metabolism first, some even land somewhere in the middle. It is evident though that information had to be held through aperiodicity, such as in the order of DNA bases, to allow reproduction. The idea that this information came about through simple interactions of building blocks is just simply astonishing to me.

I won’t go on to explain any of the theories of life’s origin, but I will leave you with something to let stew in your mind: if complex beings like humans developed after billions of years through interactions governed by the building blocks, what kind of other life forms do you think exist? Did they develop just like us? Are they based in DNA? Has any of our biological information escaped and become a template for life somewhere else, or could that have been exactly how we came about?

Pictured above is my cartoon rendering of graphene, a single layer of graphite. I really only included this because I made it, I'm pretty proud of how it turned out, and it'd make a good thumbnail when I post the link.