Nanotechnology: A Brief Overview


PREFACE

      This is a web-version of a talk I (Kevin Yager) presented to my colleagues recently. It is only a simple and surface-level foray into the vast topic of nanotechnology, meant mostly to generate interest in a field that holds tremendous technological potential. Interested readers should follow the references.

      I also wish to say at the outset that I am an opinionated writer, but by no means an expert on all the fields I am reviewing. Although I have made every attempt to be factually correct, please bear in mind that any interpretations of the research are my own. If you find any inaccuracies, or have any comments, please feel free to write me.

 
INTRODUCTION

      What is Nanotechnology? That is a difficult question, which I will leave to the end. Let us begin instead by taking a look at some of the things which Nanotechnology might be, and we will try to devise a precise definition later. For now, suffice it to say that Nanotechnology is the controlled manipulation of matter at the nanometre length scale (0.000000001m).

      Huge research efforts (with corresponding investments) in the field of Nanotechnology have been seen over the last few years. Journals dedicated to nanotechnology (such as Nano Letters) have appeared. Given the growing interest of government funding agencies, research is only going to increase. Why is it that there is such a great interest in Nanotechnology? In my opinion, there are two justifications:
      1. Control of nano-scale structure will lead to fantastic new technologies, medicines, machines, etc.
      2. We are nowhere near reaching the full potential of nanotechnology.

      How do we know that 1 and 2 are true? The best proof comes from nature, which has (over the course of billions of years of evolution) created highly sophisticated nanometre-sized devices, including catalysts, motors, data encoding mechanisms, optical sensors, etc. Nature proves that control of nanometre structure (and hierarchical structures) leads to amazing devices (able to, for example, heal, build, convert one form of energy to another, etc.). Moreover, we see that most of our technology is a pale imitation of what nature has created to solve various engineering problems.
DNA


      For example, DNA encodes all the information required to build an organism into a few molecules (admittedly they are very large by molecular standards, but can nevertheless be condensed into extremely small packages). Not only that, but DNA includes within it many ingenious error-correcting mechanisms, and 'information' which serves more to control the behavior (ex: folding conformation) of the molecule itself. This level of information compression (where a single bit of data is encoded in a molecular-sized unit) would be considered an amazing engineering achievement, if it had been created by humankind. On the flip side, we also note that DNA includes quite a bit of 'junk' sequences (which seemingly code for nothing, potentially because we don't fully understand DNA, or more likely because DNA contains relics of previous generations within it). Given this, it is tempting for we humans to imagine that we could optimize the data storage mechanism of DNA, by using it without these junk portions. In a sense, we would be improving upon nature, inasmuch as we would be optimizing it for a specific, human use.


      Another example of the startling complexity of naturally-designed systems is found in proteins and enzymes. These large polymers (or polymer aggregates) adopt very specific, unique conformations in solution (despite the unimaginably large number of potential conformations for a polymer of the given length). The specific shape of a protein is responsible for activity, and it is here that the remarkable specificity of biological chemistry begins.

 A complex biological structure: a ribosome


      Many other examples of the complexity and efficiency of biological systems exist (compare a brain to a silicon chip, compare a tree to a solar panel, etc.), but for the moment it suffices to say that the nanoscale world has great promise indeed.

 

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REFERENCES

1.Image reproduced from: Science 2001, 292, 883

 

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