Guest Writer - Gastautor - Gast Schrijver

What is Bottom Up versus Top Down?


You may have also heard a lot about nanotechnology is now about building things from the bottom up instead of from top down. This is true but let’s figure out what top down and bottom up really mean. For example, let’s say you want to design and build a house but you’ve never really built one before. Now assuming there’s no else around whom can teach you or knows anything about building, you’d first buy a simple house. You then go around renovating and remodeling the house, finding out by accident usually how a house is built, like which beams were the load bearing ones. And you’ll change your mind of course because you’ll find sometimes that things were better left alone or done another way. You get the picture - whatever you do to change the look and see how that changes your house.

In the process you try different materials or material combinations, such as deciding between brickface or aluminum or vinyl siding. Some of you may even consider stucco. Regardless, you keep doing this until you are satisfied with your understanding of how each of these approaches and ideas and their combinations will look like in a house. When you’re done, hopefully the house is still standing, but more importantly you’ve learned what you’ve got to do to make it better and design your own. This trial and error approach is like a top down approach for doing research.

Now you still don’t know exactly how to build the guts of the house but now you have a pretty good idea where all the important beams are after all your shenanigans. And if you’ve practically destroyed the house and other houses in future experiments, then you might have an even better idea how to start building from the beginning.

Like an architect, now you can begin to design houses using that knowledge. This is the bottom up approach. However, having never built a house from the “bottom up”, you’ll need to gain building construction experience to actually build what you have in mind or at least find someone who knows construction to tell you what can and can’t be done. Now it becomes the story of the “Three Little Pigs”. Well, we won’t start with straw, but your first construction assignment might be learning how to build a house with one type of material beams, such as wood. While you’re doing that, you’ve learnt what else you’ve got to do differently to make it better. You then start building houses with different materials or material combinations, maybe this time with brick or steel. More importantly, you do all this to see how close these materials can help you achieve the house design you had in mind knowing now what you know about wood and steel frame construction.

That’s not to say the top down approach will never be used again. The top down approach can still be used to design and build but it turns out to be a very inefficient and costly way to build whole custom tailored structures. Building from the top down is like making Christian Lacroix dresses or a limited edition Ferrari. Everyone feels that a custom made suit fits better than one altered off the rack. If you can make a custom made suit cost effectively, then you have something there. The matter then becomes what do you want, what is the best way to build it and with what materials to use. The point is, once we have obtained the knowledge of each type of materials used, we can build things more cost effectively to achieve the goals you have in mind. Some people like to have new houses built versus buying an old home and renovating it. It depends on your preferences and objectives. There’s always someone who says that they don’t build houses like they used to anymore. These older houses can be compared to a particular viral strain where it’s easier to just propagate them and monkey around with them. The new house building approach could be compared to wanting to make nanobots where there have never been nanobots before. Building from the bottom up is a much more cost-effective solution and if you’re a developer, you can mass produce these houses and make a fortune.

The bottom up approach with nanotechnology is akin to using ultra-tiny Lego; blocks on the molecular scale, which I call Nano-Lego. Similar to using Lego blocks you can build just about anything limited only by your imagination. If I want to build a build a plane or truck, I can do that. Once you figure out how those blocks behave under various conditions, theoretically you can build anything. The smaller the Lego blocks result in finer resolution or detail of my resulting vehicle. The smaller blocks also allow me to build smaller vehicles. Just like in real Lego, the available Lego building block options now are so much more diverse than when we were kids. Nano-Lego can be anything on a nanometer scale such as organic (carbon-based) systems such as molecules of polymer and proteins, and viruses, or inorganic systems such as silicon, boron, germanium, metallic ions, etc. Along those lines, they can even be elemental atoms themselves, like carbon, hydrogen, nitrogen, oxygen, silicon, germanium, etc. And things get very interesting at the bottom level where you start having to take into account and exploiting quantum effects. Research has been ongoing, getting smaller and smaller in focus to achieve miniaturization goals of the world, except now the Lego blocks have become small enough for us to now call it all nanotechnology.

The ultimate goal in any research is to eventually switch from a top down to a bottom up approach so this bottom up approach is nothing new. Science and research often adopts a top down approach from where to start solving its newest problems where there is little understood of a particular system.

Often some young aspiring scientists sees or reads something really neat in Star Trek which then motivates them to see if they can make it. The author of that inspiring piece either has a technical background or has really good friends in science which is why their storylines can be so believable and inspiring to the young scientific mind. Another scenario is that scientists usually observe some atypical physical behavior on a large visible scale, or macroscopic scale as they often say, and then out of curiosity, they focus down to study and find out what on a smaller scale is causing this phenomenon to happen. Once they figure out what’s going on at the bottom, they can start tweaking things on the small scale to get just the right desired properties on the large scale. Instead of tweaking things at the bottom level without understanding it and then see how it affects things at the top level, we want to understand the bottom level enough that we can just start building from the bottom to achieve top level designs. This is true for any area of research, from materials to biotech.

For instance, if you want to make a car that goes faster, you start by redesigning the engine once you understand how an engine works. Research is normally conducted this way, but it’s just that now we have the tools to observe these interactions on a scale that can now be called nanotechnology. Nanotechnology is a convenient way to group together these technologies across the board that has evolved to address behavior on that scale. Thus nanotechnology is very broad in terms of industries and technologies.

We’ll always happen upon discoveries from the top down first as is the nature of discovery. As we acquire the tools to observe behavior at even smaller scales or bottom levels, the old bottom level becomes the new top level and we begin to drill down again to find and study another bottom level. At some point, we will no longer be able to call it nanotechnology. If the physicists are right, we’ll soon be talking about “hyperspace” as Mihail Roco, Chair of NSTC confirmed to me my projections at the Nanobusiness Spring 2002 Conference in New York City in late May. After we discover the Higgs-Boson particles to exploit dimensions other than our physical three coordinates and time that we cannot even observe yet, we will be talking about hyperspace and not nanotechnology anymore. That particle is the key to unlocking our understanding of atoms at the quantum level to get us closer to unlocking the unified theory of the universe. The theoretical and particle physicists can’t seem to find it and we’ve been looking for it since the 1960’s. Actually they know it’s there but they just can’t detect it…yet. Nanotechnology then will be a distant memory.

Chances are this will not happen in our lifetime but the scientists are always proving me wrong about how clever they can be. There have been so many instances that someone has said it can’t be done in a certain time period or can’t be done at all and then some genius figures out some unconventional way to do it the following month and wins a Nobel Prize for it. A few weeks ago in late July at the World Technology Network Summit, I was listening to a government research lab scientist who specialized in carbon research. He was complaining that the potential applications of carbon nanotubes were being overhyped because they couldn’t find ways to make them interact and combine chemically with any systems. A week later I came across an article in an issue of Chemical & Engineering News from two weeks before about how scientists from University of California, Los Angeles, University of Oklahoma, and University of Negev in Israel had discovered ways to coat carbon nanotubes in starch-based molecules to make them dissolve in aqueous (water) solutions that were stable for weeks. This has major implications in inexpensive purification processes, drug biocompatibility, storage and delivery modes.

Science is unpredictable. Expect the unexpected.

Dr. Pearl Chin has an MBA from Cornell, a Ph.D. in Materials Science and Engineering from University of Delaware's Center for Composite Materials and B.E. in Chemical Engineering from The Cooper Union.

Dr. Chin specializes in advising on nanotechnology investment opportunities. She is also Managing General Partner of Seraphima Ventures and CEO of Red Seraphim Consulting where she advises investment firms and and startup firms on the business strategy of nanotechnology investments. She was Managing Director of the US offices and co-Managing Director of the London offices of Cientifica. Prior to that, she was a Management Consultant with Pittiglio Rabin Todd & McGrath (PRTM)'s Chemicals, Engineered Materials and Packaged Goods group. Dr. Chin will be advising the Cornell University JGSM's student run VC fund, Big Red Venture Fund (BRVF), on investing in nanotechnology.

She is a Senior Associate of The Foresight Institute in the US and was the US Representative of the Institute of Nanotechnology in the UK. She was an alternate finalist for a Congressional Fellowship with the Materials Research Society. She was also a Guest Scientist collaborating with the National Institute of Standards & Technology (NIST) Polymer Division's Electronic Materials Group under the US Department of Commerce. Dr. Chin is a US Citizen born and raised in New York City.

© Pearl Chin April 2004




Dr. Pearl Chin