Notes on Original Nanotech Paper

Transcription

1 Notes on Original Nanotech Paper

2 The key new thing needed III Surface issues get more important A solution: Place each atom deliberately This is a completely new way to manufacture things Do cells do it this way?

3 Citation K. E. Drexler Molecular Engineering: an Approach to the Development of General Capabilities for Molecular Manipulation Proceedings of the National Academy of Sciences Vol. 78, No. 9, pp »Sept. 1981

4 Abstract Objective: designing protein molecules To fabricate devices Advance microtechnology (What's that?) Involves building molecular machinery Implications: computational devices manipulate biological materials

5 introduction There's plenty of room at the bottom 1959 talk that helped inspire this Strategy outline: Using macro-scale machines... make smaller machines & use them to make even smaller machines»...eventually, process must end»where must it end?

6 The key new thing needed As parts get smaller, noise (i.e. roughness ) Goes from a surface finish issue to a decisive limiting factor If surface imperfections are +/- 1 micron... Then what happens when part size is a micron or two?

7 The key new thing needed II Surface issues get more important Surface imperfections get more important...and... Surfaces get proportionately bigger What is the surface area:volume ratio for A 10x10x10 cube? A 1x1x1 cube? A 0.1x0.1x0.1 cube? A nanocube?

8 The key new thing needed III Surface issues get more important A solution: Place each atom deliberately This is a completely new way to manufacture things Do cells do it this way?

9 The key new thing needed IV Surface issues get more important Solution Handle atoms individually, instead of en masse as pieces of material

10 Section Protein Design Biology builds objects up from smaller pieces (molecules) In contrast, we're used to building objects down from larger pieces Both approaches then use the pieces to build more complex things

11 Section Protein Design (cont.) Biology builds objects up from smaller pieces (molecules) In contrast, we're used to building objects down from larger pieces We should try it the biological way

12 Section Protein Design (cont.) Biology builds objects up from smaller pieces (molecules) We should try it the biological way Ribosomes exemplify a molecular synthesis tool Ribosomes themselves self-assemble More generally, bio systems rely on diffusion and binding locations to self-assemble

13 Section Protein Design (cont.) Claim: nature tends to create proteins with hardto-predict folds (tertiary structure) But engineers could & should design proteins with easy-to-predict folds Thus we can design proteins of desired shape How?...strategically placed charged groups, polar groups, disulphide bonds, hydrogen bonds, and hydrophobic groups

14 Section Molecular Machinery Table 1 analogizes between conventional mechanical parts and molecule-scale parts Struts and beams...microtubules, cellulose Cables...fibrous proteins like collagen Connections...intermolecular attractions Motors, pumps...cilia, flagella, membrane structures Electricity, gasoline...atp Containers...vesicles Computer numerical control...central dogma

15 Section Molecular Machinery Capabilities that can be transferred from macroto microscopic Move molecular objects Position molecular objects Push and connect molecular objects Inspect results

16 Section Molecular Machinery Bootstrapping can extend from proteins to anything Proteins can be extended with posttranslational modifications These include non-protein pieces Thus, we are not limited by the capabilities of amino acid sequences Use extended proteins to make arbitrary nonprotein structures This eliminates constraint of environment friendly to proteins

17 Conclusion Bootstrapping Restarts computers Can enable small machines to make smaller ones Can enable ribozyme-based organisms to transition to protein Can enable protein-based nanotech to transition to arbitrary chemistries Which an enable nanomachines to function in biologically hostile environments

18 Complex Nanomachines: Existence Proof Nanomachines exist We call them cells