Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!cs.utexas.edu!bcm!dimacs.rutgers.edu!aramis.rutgers.edu!athos.rutgers.edu!nanotech From: erich@eecs.cs.pdx.edu (Erich Stefan Boleyn) Newsgroups: sci.nanotech Subject: Re: Diamonds? Keywords: diamonds, bones Message-ID: Date: 5 Apr 91 03:04:49 GMT Sender: nanotech@athos.rutgers.edu Lines: 43 Approved: nanotech@aramis.rutgers.edu toms@fcs260c2.ncifcrf.gov (Tom Schneider) writes: > ...So why don't living things use diamond? Or do they? If >they don't, is this telling us something about the limits of nanotechnology? >That is, maybe diamond can ONLY be made at high pressures and/or temperatures, >so a molecular machine couldn't do it, unless the machine operated under those >conditions. Not necessarily. Consider how diamond is produced... the intense temperatures and pressures are necessary because there is inherently a large energy input required to produce diamond. If you look at the chemical reaction, the activation energy is large, but there is no product energy, and since the energy required is so large, it is very slow. >It's clearly possible for cells to deal with crystals. We know of bacteria >that make magnets, that trigger ice formation (!) and lots of other cases of >mineral deposition, such as bone formation: Crystals are somewhat easy to produce... so biologically, most of what is done is making the production easier... usually by making the materials easily accessible, maybe even catalyzing the reaction. >Cells handle carbon structures all the time, so why are shells and structural >components mostly silicon and calcuim? The person who figures out how to get >a cell to grow a diamond may become rich! The energy required to do this as opposed to making crytals that have a small associated energy would be enormous. Imagine all of the food required to power those cells! Normally, organisms evolve into routes where the energy expenditure to try out a new idea is sufficiently small so that it is "worth" attempting. The bio-engineering necessary to make this thing work would be quite an achievement... worthy of some of the better science-fiction written. Erich "I haven't lost my mind; I know exactly where it is." / -- Erich Stefan Boleyn -- \ --=> *Mad Genius wanna-be* <=-- { Honorary Grad. Student (Math) }--> Internet E-mail: \ Portland State University / Phone #: (503) 289-4635