Question About Organic Nano-Manufacturing
brettl writes "Question for a sci-fi story that would like to have some sci in the fiction. If an organ (or person) could be mapped at the molecular level, wouldn't the cost of nanofabricating an organ, a limb, or a person be equivalent to the cost of manufacturing any sort of organic product of equivalent mass (ie plastics)? Or would the complexity increase cost/time of manufacturing? Or would it not be possible at all? Would it be cheap? Also, opinions on how this would play out in reference to the current bioethics debate on cloning would be interesting. Thanks"
October 24th, 2003 at 4:54 AM
"We have the technology to rebuild him. Fries?"
I would expect fabrication of biologically identical tissue structures to present it's own special problems and that a molecular assembler capable of assembling plastics (or diamonoid materials) would have problems with biological tissues. The differences in the technology paradigms being the source of most of the problems.
Biological "nanomachines" are "wet", with most of the active mechanisms in solution. The water is an instrinsic part of the mechanism, being used as both a means of transport and a provider of structural strength through hydrostatic pressure. Having most of the machine parts in solution produces a chaotic system, but one that can tolerate a certain level of contaminants. Biological systems use a great deal of self-assembly, which is compatible with these chaotic solutions.
Drexlerian nanomachines are dry phase ; structure and transport are distinct and seperate mechanisms. Since they rely on precise alignment of their components with zero contaminants, watery solutions should really be confined to systems like component seperators. This approach is far more controllable.
I started off thinking that manufacturing biological cells with "dry" nanotech would be next to impossible, because of the water involved, but you've made me think about it and I think I have a reasonable approach … I think a nozzle which extrudes cellular membranes around it's edge (complete with membrane transfer proteins, etc) whilst filling the cell in the centre with the relevant organelles (manufactured seperately) and solutes, as well as water, could be made to work ; but it would be LOT of work to get right ; our understanding of cellular biology is far from complete.
It would be far easier to leave the biological stuff up to "Mother Nature" ; cells have been making new cells for billions of years.
A system that combined a "dry" nanotech cellular positioning system, coupled to a network of tissue cultures providing the distinct cell lines required to assemble the required organ or limb. You could use genuine cellular adhesives, or biocompatible nanotech analogues. Arms could position the cells into the correct arrangements and allow them to bond with their neigbours, in a somewhat larger version of the molecular assembler (the cellular assembler, if you will). If you could get the "cell extruding nozzle" system above to work, you could just replace the tissue cultures with cell extruders at a later date.
If you are willing to make compromises and have a limb that is not 100% biological, substituting nano-analogue materials would offer greater efficiencies. A fair approximation of bone compatible with the normal bone tissue cells (osteoclasts, osteoblasts, marrow cells) would eventually be remodelled into "real" bone, for example.
Replacement of body systems with "dry" nanotech equivalents would offer superior functionality and probably with a lower investment of research. Purely structural systems would be easiest to replace ; followed by systems with relatively simple functions like muscle tissue. Complex endocrine tissues would be hard (we'd have to understand the feedback loops better), and of course, brain tissue would be the hardest.
Of course, for a sci-fi work, you can gloss over some of the detail….
October 24th, 2003 at 7:53 AM
Re:"We have the technology to rebuild him. Fries?"
What about producing "typical" cells? Call it my average cell for each of my cellular types. Then we'd need less info about each cell. Just a type, location, orientation, and maybe some type specific stuff. You'd have to do some sort of population sampling to make sure you got a "typical" cell, and that one would have to be mapped with extreme accuracy. Obviously this does gloss over your problem of building cells with any sort of efficiency, and we'd REALLY gloss over the whole brain problem. But this is not TOO out there is it? Any cell should be able to replace a cell of the same type so long as both are produced by the same body, right?
October 26th, 2003 at 8:40 AM
Re:"We have the technology to rebuild him. Fries?"
You are asking a number of very complex questions. Will the cost be as low as an equivalent mass of plastic? No. Why? Because you don't have to manufacture plastic in a sterile environment. The easiest way to do this is to "grow" it using cells with genomes engineered specifically for this purpose. People at MIT, Genzyme, and other organizations are working on the initial approaches to these methods. You lay down (print?) a matrix, seed it with cells and let them multiply. The problem is that with natural eukaryotic cells you are limited to a 24 hour cell division time so it takes some time to grow an adult sized organ. That takes up valuable lab space and therefore makes the resulting product moderately expensive. Now you can probably push on things — perhaps raise the temperature, oxygen, glucose and other nutrient concentrations, etc. but to really do it right you want to engineer the genome so there is no junk DNA, and the only genes in the cells are those that are precisely necessary to produce the organ you are interested in. That way you may be able to push the cell division time down to only a few hours. (Bacterial cells can replicate in as little as 20 minutes but they don't have the material transport and internal structural complexity that eukaryotic cells have.)
Generally speaking with natural genomes, any cell can replace any other cell (even cells of different types) *if* you know how to turn specific cellular differentiation regulatory genes off and on. In the scenario I outline above, that ability would be sacrificed in that cells would have "limited" genetic programs designed to rapidly grow into specific tissues. The less time it takes to grow (assemble) a tissue (organ) in a lab, the less expensive it is going to be.
You don't need nanotechnology to accomplish this — you simply need moderately robust biotechnology.
October 27th, 2003 at 10:03 AM
Why is this cheaper/faster/easier?
Than the assembly methods that are laid out in Drexler's Engines of Creation? It seems to me from reading that a pretty efficient (much faster) way to do this is assemble cell walls first and then assemble organelles and various cellular machinery from there. Maybe I'm reading to much into the lit, but as I recall his scenario speaks of hours rather than days.
October 27th, 2003 at 5:30 PM
Re:Why is this cheaper/faster/easier?
A directed assembly process may be somewhat faster than a self-assembly process. This is particularly true if the directed assembly process is optimized for the assembly of object(s) being assembled. However, you have to focus on two very important factors — nutrient delivery and heat removal. Bacteria can replicate every 20 minutes but they require significant mass transport augmentation to supply the nutrients they need to do this. High concentrations of nanotechnological activity also face a heat removal problem.
You can get hours if you have a highly concentrated energy source and an efficient way to remove waste heat. But that is not a typical environment. Of course such resources might be constructed but it is likely that people will observe you in the process of doing so. Whether or not such observations remain a deterrent is something that remains to be determined.
October 28th, 2003 at 10:03 AM
Re:Why is this cheaper/faster/easier?
Thanks much for all of your help. I appreciate you taking time to educate me.
November 7th, 2003 at 8:38 PM
First hurdle: the scan.
It's hard to put the sci into this one, particularly in view of the biocompatibility issues that others have addressed. We're actually very fragile organisms without our self-repair machinery turned on. Maybe an on-body regrowth paradigm would come closer to dealing with biocompatibility issues than a vat-based one.
There is another stumbling block that you need to consider though, not just early on in the process of rebuilding but throughout it. Engineering construction pretty much requires both an exact static blueprint of the end item and detailed understanding of the dynamics of how it functions. We are nowhere near to being able to provide a hypothetical nanoconstruction engineer with either of these, and quite possibly the very concept of a static blueprint is not meaningful unless we can invent or at least postulate a mechanism for instantaneously capturing the complete molecular state of an organic physical system. This does seems unlikely on this side of a singularity. (:-) In the absence of instantaneous capture, a progressive scan might yield a map that is "good enough" for directing the build process, despite a myriad of problems relating to moving goalposts, non-destructive deconstruction/reconstruction, as well as the easier non-biological issues of process direction and data transport. The amount of sci available in this area of the problem is, sadly, very low.
It's nice to see a desire for a degree of scientific accuracy in sci-fi, but don't let that get in the way of good storytelling and characterization. The author's pen is far mightier than the engineer's toolkit at this stage.
November 7th, 2003 at 9:42 PM
Bioethics debate on cloning
Also, opinions on how this would play out in reference to the current bioethics debate on cloning would be interesting.
I couldn't help but chuckle at the image that this conjured up — the aboriginal shaman, reaching deep inside his treasured resources of cultural insight and ancient wisdom, pronounces on the bioethical issues of state variable feedback control systems in the European jet fighter. (:-)
As they say in these parts, "It's good to talk". Whether it's productive.to talk though is a different issue altogether, and depends in large measure on being able to gather advisers with good insight, appropriate background and acceptance of change, while weeding out those with personal agendas. Needless to say, it won't be easy.
December 20th, 2005 at 12:52 PM
I think your views are horrible. They show no real evidence and lay claims that based on scientific research are crazy. I just wanted to voice my opinion like you did yours. In the future I would appreciate if you would avoid writing such bogus material. If you really knew your stuff you could have gotten specific and practical. You may need some more education and I would be happy to teach you something that is not based on theory. Please avoid from this sort of mindless dribble in the future.