A few months ago I was asked the question,
"If I wanted to one day become a nano-engineer who designed nano-robots, what subjects should I study?"
I thought for for a while before reluctantly answering with something like, "NEMS and and anything quantum." I knew that wasnīt the best answer, but I couldnīt think of anything else. Those just happened to be the things I thought were important while I tried to figure out quantum biology and which stocks fit into The Nanotech Sector. After a bit more thought and a literature search, I thought of a better response, engineering.
The objective behind nanoengineering isn't much different from ordinary engineering; that is, to design and assemble functional devices from the available components. Nanoengineers are already assembling those components into functional devices such as nanoparticle films [1] for space aged coatings and gene chips for medical diagnostics. Furthermore, assembling molecular components into circuits for bottom-up integration is a promising route towards the fabrication of really fast quantum computers. With these examples as a few motivating factors, rapid progress is being made in our ability to plan and carry out molecular assembly.
A diverse array of components is available to the nanoengineer who wishes to use bottom-up design for the fabrication of devices such as a "nano-robot." Biological compounds such as nucleic acids, proteins and lipids are particularly promising components since they are already known to carry out important nanoscale functions in biological systems. Synthetic and semi-synthetic components are also useful for nanotechnology. Quantum dots, one-dimensional wires and molecularly thin films are a few examples.
Assembly of these components requires some technique. One way to assemble nanodevices is through biomolecular self-assembly. Biological compounds frequently have the innate ability to spontaneously assemble into the nanoscale machinery that makes life possible. Self-assembly of synthetic components is also common practice among nanoengineers. For instance, strategically shaped computer chips can be designed that self-assemble into functional 3D networks [2]. Another promising method is through the use of localized fields, for instance, those generated by MEMS components such as comb drives [3].
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Reference:
[1] MoS2 Nanoparticles as Solid Lubricants
Cage-like nanoparticles composed of MoS2 have been found to be effective solid lubricants which may be useful in practical environments (besides space). Similar materials such as graphite and 2D MoS2 sheets also function as solid lubricants, but only work in a vacuum. These fullerene-like particles continue to reduce friction and endure rubbing in ambient conditions. Measurements of the friction and wear-rate of other solid lubricants were made until failure, but the nanoparticle film apparently wore out the experimental apparatus before its lifetime could be measured.
M. Chhowalla and G. A. J. Amaratunga, 'Thin films of fullerene-like MoS2 nanoparticles with ultra-low friction and wear' (2000) Nature 407, 164-167. abstract
[2] 3D Electrical Network Self-Assembly
In order to find a more efficient way of assembling computers in three dimensions, Whitesides and coworkers strategically patterned polyhedra to self-assemble into 3D electrical networks. Truncated octahedra with solder on the square faces and LEDs on the hexagonal faces were assembled by placing the elements into a hot, isodense, aqueous KBr solution. In this environment, the solder melts and the millimeter-scale components spontaneously assemble into ordered structures. The faces involved in the assembly all had the same solder pattern in order to maximize the assembly rate. In the future, the authors proposed replacing the LEDs with processors and the use of hierarchical and shape-selective self-assembly as promising improvements.
D. H. Gracias, J. Tien, T. L. Breen, C. Hsu, G. M. Whitesides, 'Forming Electrical Networks in Three Dimensions by Self-Assembly' (2000) Science 289, 5482, 1170-1172. Abstract
[3] P. A. Smith, C. D. Nordquist, T. N. Jackson, T. S. Mayer, B. R. Martin, J. Mbindyo, and T. E. Mallouk, 'Electric-field assisted assembly and alignment of metallic nanowires' (2000) Applied Physics Letters 77, 9, 1399-1401.
