LMR - Research (This page was written in the late 1990s)



The Nanorobotics Manifesto

The microelectronics revolution of the past decades has had a profound effect on the way we live, and is responsible in no small measure for the prosperity of many regions of the world. It has been a major factor in the development of Computer Science and in the important role that CS plays today. The next frontier in miniaturization is nanotechnology. Its effects are likely to be even more marked than those of its microscale counterpart, because the atoms and molecules that form all matter have dimensions on the nanoscale. Nanotechnology promises to give us unprecedented control over the structure of matter, thus leading to small, fast, and cheap devices with new functionalities, and to materials with novel properties.

Nanoelectronic and nanoelectromechanical systems (NEMS) such as sensors, computers and actuators will bring about a new era of micro and nanorobots, and will play an important role in the emerging paradigm of ubiquitous interaction, which is likely to be central to information technology in the 21st century. Highly mobile humans and robots will be able to interact with enormous amounts of information, and also with the physical world through large numbers of distributed sensors and actuators, most of which will have extremely small sizes.

The importance of nanotechnology is becoming widely recognized, from congressional hearings to the scientific literature and the popular press. The nanoworld is extremely interesting scientifically, because the properties of nanoscale objects differ from those of bulk materials. The potential applications of nanorobots are revolutionary. For example, they may be used to interact with single molecules. This will open new vistas in Chemistry, which until now has dealt primarily with very large ensembles of molecules. Applications in nanobiotechnology are especially interesting. They range from programmable artificial cells, which themselves are microscale devices built with nanoscale components, to smaller nanorobots capable of entering cells and repairing them. Rapid detection of pathogens by nanosensors swimming in the blood, and immediate response to them via artificial cells may revolutionize medicine.

Two major issues must be addressed: building nanorobots, and programming them. The two are inter-related because the minute sizes of the devices will almost surely place severe constraints on their programmability. For example, it seems unrealistic to expect that a nanorobot will contain a Pentium and communicate via TCP/IP. At least initially, the devices will have very limited capabilities. Nanorobot programming will likely be an extension of current work on distributed mobile robotics and sensor networks. Nanorobot construction must deal with sensors, computers, actuators, power, and communications, all at the nanoscale.

Artificial nanorobots do not yet exist, and nanostructure fabrication is still in its infancy. A bootstrapping approach for nanorobot fabrication consists of using robotic technology itself to assemble molecular-sized building blocks by using Scanning Probe Microscopes (SPMs). The nanoassembly approach is being investigated by us at USC's interdisciplinary Laboratory for Molecular Robotics (LMR), and by a small number of labs around the world. In SPM-driven nanoassembly, the components are positioned by using the tip of an SPM as a manipulator under computer control. SPM manipulation is an interesting problem in robotics. It can be likened to a mobile robot (say, a helicopter) mapping a terrain and navigating over it by using only altitude radar and dead reckoning in the presence of large spatial uncertainties. Joining of positioned nanocomponents can be achieved by several means demonstrated in our lab and elsewhere: by using chemical glue (e.g. DNA), by depositing additional material over the original assembly that serves as a template, simply by sintering (heating) or by "welding".

We are also exploring other approaches to nanorobot component construction, by using nanowires and nanotubes as sensors, electroactive polymers as actuators and fuel cells as power supplies.

In short, we are taking the first steps towards nanorobot construction, and we intend to study how to program nanorobots for useful tasks, especially in environmental and biomedical applications.


Research

A major focus of our past research has been the development of high-level systems for programming a Scanning Probe Microscope (SPM) as a sensory robot, and the application of these systems to challenging nanomanipulation problems such as building prototypes for nanoelectromechanical systems (NEMS) and manipulating biological structures, e.g. DNA. This goal requires an interdisciplinary approach that blends together a systems view from computer science, state of the art macrorobotic methods, and knowledge of physical, chemical and biological phenomena at the nanoscale.

We use the tip of an SPM as a robotic hand to precisely position nanoparticles and assemble them. We are developing and integrating the various component technologies needed for nanomanipulation. These include: substrates that serve as nanoworkbenches on which to place the objects to be manipulated, and are analogous to fixtures in the macrorobotics world; tips, probes and molecules that serve to grasp others, and function as grippers or end-effectors; chemical and physical nanoassembly processes; primitive nanoassembly operations that play a role analogous to macroassembly operations, such as peg-in-hole insertions; methods for exploiting self-assembly to combat spatial uncertainty, in a role analogous to mechanical compliance in the macroworld; hardware primitives for building nanostructures; and software for sensory interpretation, motion planning, and acting (i.e., driving the SPM).

We have developed methods for positioning colloidal nanoparticles (typically gold balls with diameters 5-30 nm) accurately and reliably on mica and silicon substrates, in air or in liquids, at room temperature. Nanomanipulation in liquids opens new avenues of research on manipulation of biological materials. We also have demonstrated linkage of nanoparticle structures by using di-thiols or DNA, and manipulation of the resulting sub-assemblies. This is a first step towards hierarchical nanoassembly. We have also shown that nanoparticle patterns can serve as templates for deposition of materials at the nanoscale, and can be fused by sintering. This work has culminated in the development of a fully automatic system for the manipulation of nanoparticles with sizes on the order of 10 nm. In late 2008 this was the only such system in the world.

We have also addressed the problem of programming and coordinating swarms of thousands of nanorobots. We have developed fully distributed algorithms for building arbitrary shapes on the plane. The algorithms were validated by extensive simulations. The swarms are tolerant to large amounts of noise and self-repair in the presence of such faults as robot malfunction.

Recent research is covered in the Nanolab site.