Ever had the chance to see the paintings of Georges Seurat? Seen from afar, they may not be so striking to you, other than that they are quite beautiful works of art. As you take a closer look, though, you realize that those paintings are composed of hundreds of thousands of individual specks of oil paint! Wow, you exclaim in amazement, if not for the artistic mastery, then at least for how crazy it is for the artist to fill seventy square feet worth of canvas with little specks of paint!

When everyone else at the time was hacking away at the canvas with broad leafy strokes, Seurat gave impressionist paintings a twist by inventing pointillism. Now, at the turn of the 21st century, in the arena of science and technology, nano engineers are also paying attention to incredible details. In electronics, instead of using bulk crystals--likened to the traditional blends of paint--as the building blocks of devices, nano engineers are placing different materials together in specific configurations, at the length scale of atoms, to create structures with unique electronic properties. Advocates of bio-mimicry hope to retire traditional methods to carry out chemical reactions, where energy is poured over a statistical game of molecules randomly bombarding and interacting with each other to form wanted (and not-so-wanted) products. Instead they're inspired by assembly type reactions that occur in biological systems, where specially designed reactants and catalysts carry out processes with such precision and speed that they seem more like tiny robots than molecules driven by thermodynamic forces. Meanwhile, material scientists are enhancing the mechanical properties of everyday materials by controlling the size of their crystalline grains--regions of crystallinity--down to diameters less than a tenth of a micron.

Regardless of the field of endeavor or the physical principles involved, nano engineering is about paying attention to scales smaller than the continuous features of bulk materials and designing down to the granular details of molecules and atoms. There are many advantages to doing things this way. For one thing, there is the gain in efficiency, speed, and other performance factors that more or less scale with miniaturization, as you can readily see with the trend in computers. Researchers envision nanoscale substitutes for the components on a microchip, for example, molecular transistors and wires, that consume less power and can be more precisely fabricated. With these molecular components, chip designers will be able to lay out not millions, but billions of transistors on a single chip, increasing the performance of the computer by a thousand fold compared to those of today.

Another neat reward that comes from designing things in granular detail is the ability to give unique macroscopic properties to a material by careful arrangements of what goes on at the molecular scale. Thanks to the widely applied language of quantum mechanics, one of the best known tunable parameters related to molecular geometries are electronic states, which dictate the way the material distributes its electrons to transduce energy, by radiation or other means. Perhaps the simplest and most useful example of a product made by controlled electronic states is the quantum dot, a semiconductor crystal whose dimensions approach the size of its constituent atoms. In a bulk semiconductor crystal, the useful electronic and optical properties come from the influence of the crystal lattice, which unfortunately are pretty much fixed since it's not possible to rearrange the positions of the nuclei very liberally. On the other hand, in a quantum dot the electrons are tightly confined in a small volume, and effects of the size of the crystal on the electronic and optical properties become quite significant. Because of this flexibility, quantum dots are being rigorously developed for use in telecommunications and various imaging fields.

Finally, one of the most exciting possibilities nano engineering has to offer is molecular machines that perform mechanical feats at the molecular scale, for example, assembling atoms piece by piece to build molecules, driven by the same forces that attract molecules and dictate their conformation. As the visionary K. Eric Drexler pointed out, the biological world is full of examples of this molecular machinery, such as proteins, which are precise molecular machines that fold and interact in highly specific ways with other molecules to carry out chemical reactions, take up and release molecules, relay signals, and perform other special functions in the cell. In turn, the proteins are manufactured by ribosomes, yet another sophisticated molecular builder machine that is programmed by the DNA. While the goals of molecular machines achieved by humans may still seem quite far out, nano engineering is a promising frontier to tackle the barriers to these incredible levels of technological precision and complexity.

And progress is being made too. Single molecule transistors and diodes are currently being made on regular, albeit individual basis, that may pave the way for tomorrow's ultra dense computers. Techniques to grow aqueous quantum dots and attach them to biomolecules are accelerating research in smart bio-sensors that may be the predecessor to multi functional biomedical nanoscale probes. Molecular motors that run on ATP, the same biomolecular fuel that nature's molecular motors use to pull microtubules during mitosis, are chugging away at abysmal speeds, but are shedding light on what makes nature's sophisticated biomolecules work and may one day lead to full fledge molecular machines. Hold on to your seats!