2 INTRODUCTION
efforts deal with the application of cell mechanics to neurobiology and cancer research. C ur-
rently, a key limitation is in understanding the behavior of the myriad of different cellular
structures, interactions and adhesive forces. Once this is established, these mechanisms
can be used to develop treatment strategies for cancer, for example, in the prevention of
metastasis.
The design and production of materials from the atomic scale up is a goal that is becom-
ing increasingly realizable by the application of DNA to nanotechnology and biotechnology.
Owing to the predictable manner in which DNA strands interact, research is now being
performed to design solid materials by manipulating individual DNA strands as the basic
building blocks. Use of DNA will lead to new materials with novel mechanical, chemical
and optical properties, controllable at the unit of the basic building block.
Nanotechnology also has the potential to greatly improve our resistance to terrorism
and improve our national security by improving the technologies available to our armed
forces. Nanoscale sensors are being developed for the purpose of detecting illegal and
harmful airborne chemicals. Our soldiers will benefit from new, energy-absorbing polymer-
based nanomaterials that will provide ballistic protection while being light enough to allow
maximum mobility. Research along these crucial lines is being done, for example, at the
MIT Institute for Soldier Nanotechnologies.
Protective coatings is another area that has greatly benefited from nanotechnology.
These coatings have a wide range of applicability, examples being gears and bearings in
the automotive industry, and naval vessels for the military. In all these applications, the goal
has been to replace or augment previously known super hard materials such as diamond
in designing tribological parts that use nanoceramic-type coatings to reduce friction and
wear. Extending the lifetime of these parts is crucial, and will lead to a massive reduction
in maintenance costs for these components.
Another key area in nanotechnology is in electronics, microelectromechanical systems
(MEMS) and nanoelectromechanical systems (NEMS). For example, the storage capacity
of computer hard drives has been increased by orders of magnitude, thanks to magnetic
materials whose thickness is on the order of nanometers. Medicine is another key area in
which NEMS and MEMS devices have made, and will make, large contributions. Here,
nanotechnology can be used to dynamically image living biological systems, such that the
real-time study of bacteria and diseases can be performed.
1.2 Motivation for Multiple Scale Modeling
Current research in engineering is just beginning to impact molecular scale mechanics
and materials and would benefit from interaction with the basic sciences. For solids,
research in the area of plasticity and damage has experienced some success in advanc-
ing microscale component design. The development of carbon nanotubes is also an area
in which nanoscale research has clearly played a major role. For fluids, coupling physics
phenomena at the nanoscale is crucial in designing components at the microscale. Elec-
trophoresis and electroosmotic flows coupled with particulate motion in a liquid have been
important research areas that have had great impact in the homeland security area. Microflu-
idic devices often comprise components that couple chemistry, and even electrochemistry,
with fluid motion. Once the physics-based models are determined for the solids and fluids,