Another one: "Atomic-scale manufacturing now a reality"
https://phys.org/news/2018-05-atomic-scale-reality.html
It's about this paper:
"Autonomous Scanning Probe Microscopy in Situ Tip Conditioning through Machine Learning"
https://www.researchgate.net/p…_through_Machine_Learning
I guess this needs to be combined with the R&D results which I've posted about recently here:
Major improvement in STM control methodology.
University of Oxford:
"Postdoctoral Research Assistant in DNA Nanotechnology Applied to Molecular Additive Manufacture": link
(Only applications received before 12.00 midday on 15 June 2018 can be considered.)
More funding for APM by AMO: link
( AMO ... Advanced Manufacturing Office link )
"Evaluating Future Nanotechnology:
The Net Societal Impacts of Atomically Precise Manufacturing"
Steven Umbrello, Seth D. Baum
Global Catastrophic Risk Institute,
http://gcrinstitute.org
(2018-04-28): link
Meetup group: League of Extraordinary Algorithms -- Special Topic: Molecular Manufacturing (past - was on 2018-05-12) -- link
Paper title:
"On the effect of local barrier height in scanning tunneling microscopy:
Measurement methods and control implications"
https://doi.org/10.1063/1.5003851
I'll try to summarize in a reader friendly way.
(I found abstract and conclusion of this paper not really satisfying.)
One of the most serious issues with current STM microscopes
is their tendency to fail on some more severe surface features like e.g.
chemically highly reactive sites including dangling bonds.
(Since I've once worked with an STM (omicron) I know that pain all too well.
Exactly where it gets interesting one gets all those "shadows" where the feedback control fails.)
A simple formula for the tunneling current in STM's is like follows:
i = c*V * exp( -d * delta * sqrt(phi) )
where:
0) c*V ... some constant
1) d ... another constant = 10.25 sqrt(eV)/nm
2) i ... tunneling current
3) delta ... tunneling gap length in nm and
4) phi ... arithmetic average between probing-tip and sample work functions
Logarithmized this equation becomes:
ln(i) = ln(c*V) -d * delta * sqrt(phi)
In the usual operation range for the occurring delta values, phi is mostly independent of delta.
Written in differential form:
d_phi/d_delta ~= 0
Thus one can differentiate the logarithmized equation to:
phi = (d_ln(i)/d_delta)^2
So from the squared slope of the logaritmized tunneling current one can determine the work function average. Since this value is position dependent one can obtain a local-work-functon-image better known as local-barriere-height (LBH) image.
Now here's the problem:
Reversely, varying the current always in the same way, meaning independent of the LBH at the current position, produces different variation amplitudes of delta depending on the local work function. What most current (2018) STMs are using is PI control that uses exactly that position independent constant gain. And this is what regularly gets them into an unstable regime (a regime where the actual current widely detours from desired current) at locations with low LBH. This is leading to the aforementioned "shadows".
Here's what the papers authors did to solve the issue:
They superimposed a "high" frequency dithering signal (dither frequency was 4kHz) onto the unprocessed feedback signal such that they could determine the LBH based on the resulting current variations. (This part was not new.)
Then they use the gained LBH value to continuously (LBH estimation bandwidth was 400Hz)
re-tune the DC gain of the STM's PI controller. Re-tune the the proportional P part. (PI Feedback bandwidth was 300Hz.)
As a side-note: They used some alternative implementation of a lock in amplifier including second order band pass filters and first order Lyapunov filters. They write that they have outlined details about that in one of their preceding papers.
The results:
(Fig. 5.):
(1) Significant reduction of the unwanted correlation of the LBH images with the topography images.
(Fig. 6):
(2) At the usually wanted and or necessary high gain settings near the stability limit, sudden drops in LBH (like in case of dangling bonds) do no longer lead to PI control breakdown. The old "solution" of reducing the overall gain led to more tip-sample crashes (especially in lithography mode) due to less sensitivity and smaller bandwidth.
(Note: The shadows are no crashes. They are more like over-retracts. When lowering DC gain to reduce these shadows, this is when one gets crashes.)
They write that the usual assumption of the "gap modulation method" is that the delta dithering amplitude is constant because the modulating frequency is beyond the controller bandwidth. ("gap modulation method" == established method of feedback dithering for LBH image generation)
They write that this assumption does not always hold. Especially for fast-scanning high-bandwidth scanners.
And I take (my interpretation reading between lines) they mean the problem was not solved till now because this problem was overlooked.
All this was done with big slow macroscopic piezo based STMs.
(An in house own design STM of Zyvex and an omicron STM for comparison.)
So we are left to wonder how much this will do for fast and lightweight MEMS based STMs.
PS: Here's some news coverage with video:
https://www.nanowerk.com/nanot…ogy-news/newsid=49386.php
Primary press release: https://www.tum.de/en/about-tu…ses/detail/article/34408/
Paper (walled): http://science.sciencemag.org/content/359/6373/296
Video: (long url)
Direct link to video: https://www.youtube.com/watch?v=K9fuSVaszyg
I was very much waiting for these news.
This will go into my list of archived milestones in the incremental path.
Next up, to widen the data bottleneck, this needs to be electrically parallelized and combined with (nontrivial) nanomechanical demultiplexing.
All that while reducing self assembly failure rate and further extending and improving improving (the already demonstrated) convergent/hierarchical self assembly capabilities.
The emergence of unconventional biomineralization research is also a milestone I'm eagerly waiting for.
(Unconventional in the sense of not trying to recreate strong (but non AP) composite materials like mica but trying to create less strong but more versatile pure and AP single crystals of desired shape.)
PS: some media coverage:
nanowerk; nextbigfuture; kurzweilai
Name: "Mechanical Computing Systems Using Only Links and Rotary Joints"
(Submitted on 10 Jan 2018)
by Ralph C. Merkle, Robert A. Freitas Jr., Tad Hogg, Thomas E. Moore, Matthew S. Moses, James Ryley
https://arxiv.org/abs/1801.03534
(There was a preceding report: http://www.imm.org/Reports/rep046.pdf)
Essential points:
+) extreme simplicity, only two elements, links and and 2D rotary joints
+) (as the paper says): "All parts of the system can remain permanently connected and yet still provide all necessary combinatorial and sequential logic"
It is not mentioned in the paper like this but I think the idea (Fig.3) can be interpreted a bit more abstractly as such:
The locks provide a singular mutual dead center point where one gets an additional "singular DOF".
(Does "singular DOF" make sense? I mean a point where two DOFs cross and one can switch between the two systems. There might be a relationship to holonomic constraints: https://en.wikipedia.org/wiki/Holonomic_constraints ? Or not.)
This one additional "singular DOF" allows for temporally decoupling the downstream logic from the upstream logic without actually detaching parts (which would likely cause vibrations), and thus allows for:
1) "repeated buffer power refresh in a pipeline by clocking" and
2) "(reversible) latch memory" in sequential logic. (referring low density memory, not particularly to to high density memory like Fig.16)
3D printing demo models (as suggested in the paper - Fig.22) would be cool, but even pretty simple things (beyond the depicted 3D modeled test part) like a basic one bit full adder (Fig.6) are already pretty darn big in their maximally compressed form (which, I take, is depicted in Fig.6).
Btw: Even basic universal gates NOR or NAND (NAND Fig.5 is double sized combo with negated logic I think) are already composite structures in this "calculus".
Naively composing these composites (e.g. to the aforementioned full-adder) without a then following simplification step makes the results even bigger. (It's an uncompressed form).
Making models by cutting links form bottle plastic (HDPE / PET) with scissor and hole puncher may be viable and cheap.
Some side-notes / observations:+) IIRC Nanosystems mentions that dissipation from sliding rotation scales worse than dissipation from sliding translation. But I think this is still much better than rod logic.
+) Friction force and thus dissipation too (dissipated_energy = force * path * friction_coeff) is in first approximation independent of area (at least on the macroscale). So if force is kept constant (not pressure as in the usual case!!) then a bigger superlubricating bearing should perform not much worse than a single sigma bond bearing. Shouldn't it? I'm oversimplifying. I definitely need to more thoroughly re-read the paper "Evaluating the Friction of Rotary Joints in Molecular Machines" Ref[11]
https://arxiv.org/abs/1701.08202.
+) IMO the single-sigma-bond-bearings partially destroy the benefit of radiation hardness which the massive links provide (mentioned in intro section 5.1).
That needs to be quantized.
+) The current design (Fig.24) with its stark size mismatch between bearings and links feels rather prone to overtones, ringing, sidewards wiggling, ... .
I could be wrong there.
+) Maybe the two preceding points are just a matter of optimization focus:
Minimal dissipation (design as presented - cost in radiation hardness and size)
Maximal radiation hardness (bigger bearings - cost in dissipation and size)
Maximal compactness (smaller links - cost in radiation hardness and dissipation due to falling link stiffness)
+) Flex logic (Fig.23) seems even better for the nanoscale but bad for 3D printed models with quickly wearing high dissipation plastics.
+) I'm a bit puzzled why they've chosen pushing instead of pulling. (Well it doesn't really matter much.)
+) The transmission lines move in a reciprocative manner (just like in rod logic) ... (Had to add "reciprocative". I totally love that word.)
+) Related mechanism: https://en.wikipedia.org/wiki/Whippletree_(mechanism)
+) Bonus for mentioning Konrad Zuse and his Z1
I still haven't read all the way through the paper.
So there's a chance I've missed some important points that I would like to point out especially.
PS: I was notified about this via a google alert I set up for "atomically precise manufacturing"
This guided me to: https://boingboing.net/2018/01…s-made-purely-of-joi.html
Also I found some discussion here: https://news.ycombinator.com/item?id=16129830
Great,
IMO one of the most advanced and interesting things that are currently going on
are the SW projects of Christian Schafmeister.
Here's a presentation:
Then there also is:
http://cadnano.org/
Which I haven't yet looked into.
As for "Nanoengineer-1", AFAIK it has been abandoned by the original developers.
Eric Drexler somewhere did mention a few details about the exact reasons (can't find it right away).
I think the development ran into a dead end probably due to a combination of
* unready SW technology (especially GUI side) and
* technical debt
We really need functional reactive programming (FRP).
As far as I can see this is the only way to cleanly separate logic from interface
and have GUI programs composable instead of wheel-reinvent throwaway.
(That would change orders of magnitude in productivity.)
NE-1 was picked up by Bruce Allen ***
http://moleculardynamicsstudio.blogspot.com/
But:
* I think this might now go in a bit different direction. Straying away from APM.
It seems the focus went more to highly accurate predictions for research than for
robust feature rich development & exploratory engineering.
* NE1 is a conglomerate of deeply imperative base libraries => I'd wish for pure FRP wrappers. -- But that is not a goal.
----
Nov. 2016 I had some mail traffic with Tom Moore ( http://machine-phase.blogspot.co.at/ )
about APM related SW in general, installing NE-1 on Ubuntu, and what I would concretely wish for in particular.
Here's a crop-out of what I wrote:
"In the long run I want to see detail mipmapping, seamless zoom-out to bulk limit approximation,
black box subsystems with physical geometry and logistic IO parameters (lazy deferrable!).
And maybe polar logarithmic multi-scale view: ..."
I think system level focus this is not really where *** is going.
I also noted the major point that auto-equilibration is not scalable in NE-1 (major weak point)
and pondered about the internal implementation and ways to improve this.
Gotta look into the equilibration source-code sometime.
----
"A couple of months in the laboratory can frequently save a couple of hours in the library."
What a funny reverse formulation.
It's about avoiding the tedious rediscovering of unknown knowns.
But that sometimes works in reverse just as well.
"A couple of months in the library can frequently save a couple of hours in the laboratory."
Then it's about avoiding the tedious reconfirming of known unknowns.
----
Other things coming to mind regarding molecular modelling software: nanohive, boinc, ...
& the preparation for colour 3D printing of models I have done but with which's process I'm not very happy with yet.
Just to let everyone know,
I took an effort to dig up a large part of Eric Drexlers metamodern blog from the internet archive (all the date carrying pages).
Here are the links:
http://apm.bplaced.net/w/index…from_the_Internet_Archive
Lots of "gems" in there. 
Yeah, I've got info about this via the lifeboat foundation blog's google+ channel.
Here: (A)
# https://plus.google.com/+Lifeb…ndation/posts/7tAm7K4KVLn
# https://lifeboat.com/blog/2017…e.com&utm_campaign=buffer
# https://scienmag.com/scientist…le-of-building-molecules/
# https://www.nature.com/nature/…672/full/nature23677.html
But your link has some info-graphics.
A bit earlier another remotely related thing came in there too.
This article here: (B)
# https://plus.google.com/+Lifeb…ndation/posts/RtY1nQDJjwC
# https://m.phys.org/news/2017-0…s-predefined-regions.html
# http://science.sciencemag.org/content/357/6356/eaan6558
I'm a bit upset about the authors of the article (A).
Have you read the very first sentence of their abstract here:
http://www.nature.com/nature/j…html?foxtrotcallback=true
and checked their leading three references?
Citation: "It has been convincingly argued 1, 2, 3 that molecular machines that manipulate individual atoms, or highly reactive clusters of atoms, with Ångström precision are unlikely to be realized."
NNGNNH! ... Time for analysis why this happened ... again.
The fact that we still cite these minus sign bearing references suggests that we may still lack knowledge about both:
# the "modern" far term goal of gemstone based nanofactories and ...
# the incremental-path towards them.
(Side-note: I use "we" as in "majority" here since the authors of A are not the only ones citing these references).
Or it may suggest, that we may ruthlessly dismiss all those ideas that are not viewed by a large group as bringing (with high likelihood) economic returns in our own lifetimes. (Side-note: Personally I'm agnostic in regards to this last point.)
The work done in (A) (one of the R&D fronts of soft nanomachines) is in some respects (solution phase thermally driven assembly) relatively near to the incremental path. In some other respects very far though (utterly different far term goal - hard/stiff nanomachines ve eternal limitation to soft/compliant nanomachines)! Nonetheless (or exactly because of that) the recent amazing progress that was made in climbing the "stiffness ladder" in "hinged foldamer nanomechanics" seems to have flown totally under the radar.
I guess we are still standing way to close in front of the "bark" of the "soft nanomachine tree".
The R&D fronts of soft nanomachines are:
# by basically everyone well known for not leading up to advanced gemstone based APM and ...
# by many again and again confused (or claimed equal out of fear**) with the incremental path.
The incremental path is utterly different in its treatment of soft nanomachines as just a means to get away from those soft nanomachines ASAP and thus actually does lead to advanced APM systems.
**Part of the problem might also be conformist group-think where we try to keep our own reputation maximally safe by aggressively marginalizing our colleagues. Even if we personally would not aggressively disagree.
(Sorry for ranting.)
I found a complete backup of the whole wise-nano wiki,
https://archive.org/details/wiki-nano_wiseorg_w
It says: "Last-updated-date 2014-02-08"
Thus it's a little older than the last WaybackMachine snapshops that I had linked in the first post here.
The backup can't be viewed without (nontrivial) installation though.
I recently commented on this topic there:
https://plus.google.com/+Lifeb…n/posts/V1ouSsTkA8C?hl=de
I'll repeat that comment here slightly adjusted to fit the context of this discussion.
I found these two open papers:
informal overview:http://www.scs.illinois.edu/bu…hlights/pub32_Science.pdf
details: http://www.scs.illinois.edu/burke/files/pubs/pub32.pdf
(I've only read through the first one in detail yet.)
Here's what this "molecule making machine" is about in essence:
The the "Suzuki coupling" is used to make carbon-carbon bonds
https://en.wikipedia.org/wiki/Suzuki_reaction
like so: ...≡C-B(OH)2 + Br-C≡... - > ...≡C-C≡... + waste
To continue after a first reaction one needs pre-delivered building block molecules that are at least double capped
like so: Br-C≡...≡C-B(OH)2
But this would self polymerize. That is it would form "infinite" chains. So the solution found was to temporally cap (chelate) the boron end with a molecule called "trivalent N-methyliminodiacetic acid (MIDA fro short)" like so:
http://www.sigmaaldrich.com/ch…ights/mida-boronates.html
For purification it was found that the MIDA caps on the growing product molecules can be locked/released to/from silica particles by different solvents.
MARTINE hit the nail on the head with his comment.
I'll put it in different words:
Limitations that are obviously present:
Since this is conventional chemistry and not mechanosynthesis the yields are low and the error rates are high. Every synthesis step can easily have losses in the single digit percentual range. Thus this is only suitable for small molecules (as the work says itself) and does not scale up very far.
Limitations of this process that I'm not totally clear about are:
Can this synthesis be done hierarchically or only serially? (Hierarchically would extend scalability a bit.)
The minimal size and available shapes of the pre-delivered molecules (some shown in the more technical pdf) limit what can be made. The more informal pdf says that they can create loops – (How?). Given the shapes of the building block molecules sown in the technical pdf I highly doubt the loops can be made maximally tight and maximally close together. In other words I highly doubt polycyclic diamondoid cages can be synthesized (not to speak of strained ones).
Out of this reason I doubt that this process can be used for the synthesis of some of the small tool-tips for diamondoid mechanosynthesis (like e.g. DC10c). (These tool-tip molecules would be small enough to not suffer too much from the yield decline problem of conventional non mechanosynthetic chemistry.)
In light of "early APM" I suspect this technology could still could be useful for:
* The synthesis of light activated "motor molecules"
* The synthesis of novel side chains for foldamers (for boosting stiffness / symmetry / covalent cross linking / ...)
* ...
With early APM I'm referring to "Coarse-block APM systems" page 33:
https://energy.gov/sites/prod/…ntation%20-%20Drexler.pdf
And "modular molecular composite nanosystems" MMCNs
(are these two deemed identical by Drexler ??)
I'm NOT referring to what is shown in the INFAPM workshop video!
That is (as I currently see it) just about the "System-level tech demos" dead end in the diagram (also page 33).
----
Automated synthesis will by now certainly have gone a long way from where it was in the 1980's, but yes it's still on the very beginning (accelerating progress here). I think cheap 3D-printed microfluidics has the potential to give this area (and the area of foldamer nanosystems) a major boost.
"Least problematic focus" appears to be a goal without a solid reason. If the audience is presumed to be that emotionally sensitive, exposure to non-linear mapping is probably an effort in futility.
True, for a such a super sensitive audience that's likely "small-minded" enough to confuse physical size with significance, exposure to non-linear mapping may lead to severe psychological breakdown (exaggerating joke of course).
I guess I have the problem of too many options and a lack of criteria for narrowing them down. Choosing the least problematic focus or better: avoiding the most problematic focus seemed to be a good starting point.
Old buildings are an interesting idea, I hadn't that one.
I guess the one most widely known of these is the "Great Pyramid of Giza" best viewed form the perspective of "Pyramid of Menkaure". https://mrgris.com/projects/me…b6b7dd3@29.97271,31.12854
A bit of an issue with these old buildings is that while they themselves are interesting around them usually is not very much interesting stuff present for a long stretch. This leaves a gap in the map. I had the idea of the European "North Kap" but that had the same problem there. Also these very old buildings usually are not imaged with super high resolution (unlike e.g. city centers) so they become blurry on the maximally magnified end of the map.
I guess balancing interestingness on all size-scales is a good criterion.
This translates to looking for a kind of fractal succession. Maybe I should look here:
https://en.wikipedia.org/wiki/…inuously_inhabited_cities
since fractal coastlines (not referring to fractal dimension here as usually done) seem to have been a catalyst for "early" seafaring civilization.
Maybe: Greece Athens "Sunken Lake" (with caves unexplored to this day).
https://en.wikipedia.org/wiki/Vouliagmeni#Lake_Vouliagmeni
Viewing coordinates: 37.807075,23.786131
https://mrgris.com/projects/me…b6b7dd3@37.80707,23.78613
This place near my home: 48.132664,16.392811 has kind of a fractal situation going on.
https://mrgris.com/projects/me…b6b7dd3@48.13266,16.39281
(btw: the Alps make a nice bow in this view)
I could motivate using a place in my hometown Vienna by arguing that Erwin Schrödinger was born there.
But actually I don't want to focus on specific people.
There's a (rather un-pretty) place named: "Schrödingerplatz"
Viewing coordinates: 48.241081,16.437511 or 48.240963,16.437373
https://mrgris.com/projects/me…b6b7dd3@48.24108,16.43751
The perspective with that center lines up Vienna's four water-ways nicely.
Two further ideas I came up by using the topic of APM/MNT as a rough guideline criterion:
The "Swarovski Kristallwelten" exposition in Austria Wattens:
https://en.wikipedia.org/wiki/…allwelten_(Crystal_Worlds)
Viewing coordinates: 47.294340,11.600365
https://mrgris.com/projects/me…b6b7dd3@47.29434,11.60036
Topical focus is actually rhinestone though not gemstone.
The "Atomium" in Belgium Brussel:
https://en.wikipedia.org/wiki/Atomium
Viewing coordinates (from south-west): 50.894463,4.340803
https://mrgris.com/projects/me…0b6b7dd3@50.89446,4.34080
(This perspective from south west is best since it shows all continents and no building shadows)
The topical focus is actually nuclear technology though.
The surrounding landscape is rather flat, wheat field paved and bland.
Wikipedia (en) says: Distributing pictures of the Atomium is only legal since last year. What?!
I found an interactive version of nonlinear mapping:
https://mrgris.com/projects/merc-extreme/
(Tip: turn on satellite view)
What would be the most visually interesting while least politically, religiously, ideologically problematic place to focus at for a screenshot demonstrating that kind of the mapping?
This is already hard. Additionally asking for a place that can be easily identified by most of the worlds population is probably too much and likely leaves no results.
I found some broken citations here:
convergent assembly and its visualisation
They don't link back to the source ( which I can't find in case of the citations from Chris (CHRISPHOENIX)'s posts ).
I just wanted to share some recent developments I find relevant:
Two papers about interlocking DNA nanostructures:
https://www.researchgate.net/p…es_for_Functional_Devices
https://www.nature.com/articles/ncomms12414
While still far from atomic resolution and still a little jelly floppy like this totally goes into the direction of stiff atomically precise nanorobotics.
I hope that will convince more people that macroscale style machinery actually makes perfectly sense in the nanoscale.
An image out of this paper made it into Wikipedia.
I think it's the first CC licensed image of 3D wiremesh DNA stuff on Wikipedia:
https://commons.wikimedia.org/…DNA_origami_rotaxanes.jpg
Assuming the uploader "Materialscientist" was one of the creators (unlikely - comment to high res upload says "from PDF")
or had permission from the creators or the upload is tolerated which is not clear from what I find.
I'd love to use that image but as long as I'm not clear about the license I rather not.
On the microfluidics front there's a new website for open source R&D collaboration (created by MIT Media Lab).
https://metafluidics.org/
I see how this could notably accelerate progress if adopted by the subset of struct-DNA-nanotec (& other foldamer) researchers/developers.
One more worry:
I've recently checked for web activity of Josh Hall
https://en.wikipedia.org/wiki/J._Storrs_Hall
https://foresight.org/about/Hall.html
(googles recent time filter) and only found total silence.
And lots of dead links on his homepage:
http://autogeny.org/
He doesn't look too healthy in this video:
I hope he's all right.
Do you maybe have old links of Chris' blog for digging in the waybackmachine?
I have even worse news:
Drexlers blog "metamodern" broke down too.
There was lots of highly valuable stuff.
Just an example:
http://metamodern.com/2008/12/…-nanosystems-materials-1/
https://web.archive.org/web/20…-nanosystems-materials-1/
(maybe I'll edit in more here later)
The long inactive wise-nano wiki now broke down completely. 
http://wise-nano.org/w/index.php/Main_Page
Last surface snapshot on internet archive WaybackMachine: 2015
Just some pages:
https://web.archive.org/web/*/…org/w/index.php/Main_Page
https://web.archive.org/web/20….org:80/w/Wise_Nano:About
- https://web.archive.org/web/20…nano.org/w/Wisenano_works
https://web.archive.org/web/20….org/w/User_talk:Cphoenix
- https://web.archive.org/web/20…o.org/w/Programming_notes
I think it was maintained by Chris Phoenix.
I've looked a bit further into microfluidics
and I now think that this technology will pretty much for certain play a major role in the development towards HT-APM.
3D printed microfluidics - in contrast to those very expensive and pretty big pipetting systems found at biomedical labs -
allows at least one order of magnitude cheaper and thus much more accessible
tinkering with natural self assembly (and of course "unnatural self assembly" too - the desired engineering type that's targeting towards APM)
Maybe a cost level can be reached that is affordable even for hacker-spaces.
The main remaining cost point are the "vitamins" around the passive channel structures (like among many others pumps).
Beside reducing the costs significantly microfluidics also increase operation speed by several orders of magnitude.
This makes unguided bottom up construction of larger nanosystems much more realistic.
By now there are lost of videos demonstrating microfluidic principles (bubble handling) on youtube. Very interesting!
E.g. check out: https://www.youtube.com/channe…view=0&shelf_id=0&sort=dd
Specifically I am thinking about a matrix like system for programmable high speed automated manufacturing of 3D-DNA-voxel-bricks (there are several papers about those):
Step 1a) Start with N streams of DNA oglionucleotides (= short DNA snippets) and mix them into the accumulating droplets of M droplet streams. (The droplets grow very pretty big and essentially become stream-segments). For each steam M_i some N_j are retained (How?) the rest passes and mixes.
...
Step 1b) The M resulting streams (that deliver consecutive long stream-segments) then are routed through long individual circuits for first internal mixing and then following annealing.
...
Step 2) For second order self assembly (this has been experimentally demonstrated - there's a paper on this) repeat the process with the M long stream-segment-bubbles that now contain the desired fully assembled DNA structures (and salt solution streams). Those are now replacing the N DNA oglionucleotide streams that where present in the first processing round. (Obviously if the same channel-circuitry is used for step 2 it needs to be flushed out first.)
...
Step 3) Extract the product assemblies and analyze the results.
Maybe assemble some early productive nanosystem (featuring some hinges and nano-robotics)
(though with - for the time being - still stealthy and publicly unperceived small scale products)
Motivated by that exciting prospect I recently began to port the
discrete element microfluidic designs that where presented in the papers [1] and [2] (linked below) to OpenSCAD.
This will make it possible to:
1) quickly adjust the systems components geometries to the specific need at hand
(I'm not referring to the systems inherent quick adjustability here. Which is a strong point on it's own.)
2) print the systems components even on cheap FDM printers (which can be tuned to be sufficient for the job as shown in paper [0]).
PAPERS:
0) Title: "Simple and Versatile 3D Printed Microfluidics Using Fused Filament Fabrication" (Cardiff University)
1) Title: "Discrete Elements for 3D Microfluidics" (2014)
2) Title: "Predicting the behavior of microfluidic circuits made from discrete elements" (2015)
LINKS:
0) https://www.researchgate.net/p…used_Filament_Fabrication
1) https://www.researchgate.net/p…ents_for_3D_microfluidics
2) https://www.researchgate.net/p…de_from_discrete_elements
When doing DNA origami to form lots of atomically precise nanoscale parts with different shapes/topologies there's the need to mix a lot of different combinations of a lot of different DNA oligomeres.
AFAIK currently for such large scale mixing projects robotic pipetting systems are used that are not easily accessible.
Microfluidic systems may have the potential to replace such huge and expensive robotic pipetting systems.
Here's some new work investigating in how far cheap FDM printing can be used for microfluidics.
http://journals.plos.org/ploso…1371/journal.pone.0152023
