molecular nanotechnology

molecular nanotechnology
Inventors	K. Eric Drexler
Inception	1980s
Related	Nanotechnology, Molecular engineering, Molecular self-assembly

molecular nanotechnology. Molecular nanotechnology is a proposed advanced form of nanotechnology centered on the concept of molecular assemblers, as popularized by K. Eric Drexler in his seminal 1986 book Engines of Creation. This vision involves the precise, atom-by-atom or molecule-by-molecule manipulation of matter to construct complex, molecular machines and products from the bottom up. It is distinguished from broader nanoscale science by its focus on mechanosynthesis and positional assembly at the atomic scale, drawing inspiration from biological systems like the ribosome.

Overview

The foundational vision was articulated by Richard Feynman in his 1959 lecture "There's Plenty of Room at the Bottom", which speculated on direct manipulation of individual atoms. Decades later, K. Eric Drexler, then at the Massachusetts Institute of Technology, expanded these ideas in his PhD thesis and the book Engines of Creation, introducing key concepts like the molecular assembler and grey goo. This vision sparked significant debate, notably a famous exchange in the pages of Scientific American between Drexler and the Nobel laureate Richard Smalley, who raised the "fat fingers problem" and "sticky fingers problem" as fundamental obstacles. Proponents argue the field is an inevitable extension of molecular engineering, while critics often associate it with speculative science fiction.

Fundamental concepts

Core principles include mechanosynthesis, the use of mechanically guided chemical reactions to build structures, and positional assembly, where components are placed with atomic precision. The theoretical molecular assembler, a device capable of guiding these reactions, is often compared to biological nanomachines such as the ribosome found in cells. Another central concept is the molecular mill or nanofactory, a larger system where assemblers work in concert. These ideas rely heavily on theoretical frameworks from computational chemistry and molecular dynamics simulations, pioneered by researchers like Ralph Merkle at the Institute for Molecular Manufacturing.

Approaches and techniques

Research pathways include biomimetic approaches that seek to adapt biological machinery, such as DNA origami pioneered by Paul Rothemund at the California Institute of Technology, and protein design efforts. Scanning probe microscopy techniques, like those developed at IBM Research laboratories, notably the IBM Almaden Research Center, allow for the manipulation of individual atoms, as demonstrated in the creation of the "IBM in atoms" logo. Other strategies involve molecular self-assembly driven by molecular recognition, as seen in the work of Jean-Marie Lehn and Fraser Stoddart, and the development of synthetic molecular machines, for which Ben Feringa was awarded the Nobel Prize in Chemistry.

Potential applications

Envisioned applications are transformative, including molecular medicine with nanorobots capable of targeted drug delivery or cellular repair, as conceptualized by projects like the Respirocyte from the Foresight Institute. In materials science, it promises ultra-strong, lightweight materials like diamondoid structures theorized by Robert Freitas. It could revolutionize manufacturing through atomically precise manufacturing, reducing waste and energy consumption. Further applications span advanced quantum computing components, efficient molecular electronics, and environmental remediation technologies. The National Nanotechnology Initiative in the United States has long-term goals encompassing some of these visions.

Challenges and risks

Significant technical hurdles include the aforementioned fat fingers problem and sticky fingers problem related to atomic manipulation, thermal Brownian motion disrupting control, and the immense complexity of reliability engineering at the molecular scale. Societal and ethical risks, often debated by organizations like the Center for Responsible Nanotechnology, include potential economic disruption, arms race dynamics leading to new classes of weapons, and existential risks like the hypothetical grey goo scenario of uncontrolled self-replicating assemblers. These concerns were examined in reports by the Royal Society and the United Kingdom Parliament.

Current research and development

Contemporary work is more incremental, focusing on enabling technologies within broader nanoscience. Major research occurs at institutions like the Kavli Institute of Nanoscience, the International Institute for Nanotechnology, and corporate labs such as Hewlett-Packard Labs. The DARPA program "Atoms to Product" aims to bridge atomic-scale assembly to macroscopic objects. Advances in DNA nanotechnology from labs like that of Nadrian Seeman and in synthetic molecular machines continue to demonstrate principles of controlled molecular motion and assembly, steadily advancing toward more complex systems.

Category:Nanotechnology Category:Emerging technologies