Print a Plant Project

With all of the talk about printing cells and tissues... I'd like to start a thread where we can really take a look into the issues of printing cells, for both animals AND plants. Furthermore, what about printing microalgae, etc? My first Mendel has yet to arrive, but I've got an educational background in biomedical engineering, and would be glad to help spearhead and hopefully begin such a project...

From what I know right now, there are quite a few challenges to meeting this objective...

1. Make a RepRap that's accurate to 10 micrometers (.01mm?)
2. What kind of print head design would work best to print an animal cell? a plant cell?
3. How do we make the system stitch cells into tissues?

On the other side of the printing, we need to figure out scanning and structural systems.
4. What kind of scanning do we have available for living tissues?
5. What modeling systems and software do we have to simulate and analyze cell and organ structures and interactions?

These are a few questions that need to be answered, and as more research comes along, I'll post my progress.

1. Make a RepRap that's accurate to 10 micrometers (.01mm?)
For prototyping purposes, a commercially available benchtop cnc router might make be useful to prototype and to get to "hello world".
K2CNC, 14" x 14" model

Obviously, we'd want to do up an opensource machine at some point.

2. What kind of print head design would work best to print an animal cell? a plant cell?
I think folk use inkjet cartridges, either repurposed ink-type or purpose made research-type.

We've got some inkjet research here:
http://reprap.org/wiki/A5_Powder_bed_printer
http://forums.reprap.org/feed.php?153,71274
and here:
http://reprap.org/wiki/Reprappable-inkjet

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-Sebastien, RepRap.org library gnome.

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Remember, you're all RepRap developers (once you've joined the super-secret developer mailing list), and the wiki, RepRap.org, [reprap.org] is for everyone and everything!

> 1. Make a RepRap that's accurate to 10 micrometers
> (.01mm?)

A much finer (and slower) gearing system fixes that issue.

> 2. What kind of print head design would work best
> to print an animal cell? a plant cell?

There's a large amount of debate over that. HP thermal inkjet heads are often used, but you have to balance the
heat to make the bubble versus the heat tolerance of the cells. Epson piezo style heads are another option, but
you have to balance the pressure wave against what the cell can handle - and the heads clog often. Direct pumping
with a syringe pump, peristalic pump, or air seem to work best for the cells, but are near impossible to get to do just
one cell out at a time.

> 3. How do we make the system stitch cells into
> tissues?

I don't know about plant cells, but (most) animal cells will join together if they are touching and have food.
Of course tissues are more than just groups of the same cells, there are also pores, blood vessels, nerves,
connective tissues, etc. within a tissue.

>
> On the other side of the printing, we need to
> figure out scanning and structural systems.
> 4. What kind of scanning do we have available for
> living tissues?

I don't think Reprap has a scanning system built into it yet, so the cheapest way to scan living tissues is to use
a microscope with a digital camera on it.

> 5. What modeling systems and software do we have
> to simulate and analyze cell and organ structures
> and interactions?

I'm not aware of a realistic modeling system for cell or organ structures. There's software out there that can
predict cell growth and death rate under given conditions and nutrient uptake and waste output, and some
cellular interactions; but I haven't seen anything yet that could accurately give results with less than a 25% error rate.

Thank you this is what I mean.

Oooops no link.....

Printing anything novel and new is a great thing to do, so in so much as this is all of that it is a great idea.

On resolution.

This is far easier to acheive than is at first obvious and has been touched on lots of times within this forum perhaps a way's back though. So I will mention a more obvious method. Viktor has a bunch more too having done a whole bunch of micro positioning work. (He is a bit of a guru on this)

M6 threaded rod has a displacment of 1mm per revolution. If directly driven by a stepper motor of 200 steps per revolution it will have a resolution of approx 0.005mm. This is without applying micro stepping.

Micro stepping can add additional resolution but also can reduce accuracy & precision at positions that are not a full step position.

So using good quality (Stainless steel is usualy better for this) M6 threaded rod as a lead screw to drive an axis will give you the resolution you need.

For accuracy and precision you are gonna have to build something and see how it comes out.

These can be improved by adding backlash reduction strategys (A spring between the two nuts used on the lead screw) See the earlier Darwin's table corner lead screws for how this all works.

I would start off with Brass M6 nuts on a stainless steel M6 threaded rod as a lead screw.

Most reprap machines use belts for speed as they don't need such high resolution nor precision & accuracy.

A machine that featured an X Y leadscrew table would allow you to put what ever on the table and do initial experiments. The Z axis would be a single axis (fixed in the X & Y dimensions) asembly over the table that just went up and down. On this you could mount whatever droper/printhead you wanted.

This machine will never be overly fast because it uses lead screws. But should give you a start point for experimentation.

It would of course be able to be controled using any of the usual RepRap control electronics. I would be tempted to go for a ramps setup with the larger arduino mega (2560) to give lots of firmware tinkering space.

Hope this helps with some initial ideas for discusion.

Printing mycoproteins in a way that made it grow to aproximate the structure of meat rather than post processign would be fun.

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Necessity hopefully becomes the absentee parent of successfully invented children.

Glad to see some response with regards to the positioning technology that would give us the necessary accuracy. I think the most important question now, is how can we extrude the plant cell? Typically, plant cells have cellulose, and this gives the cell membrane a structural rigidity that is not present in animal cells. How can we move forward with building an extruder that is compatible with cellulose?

suspend it in medium maybe?

Thanks for the tips from nowonwards I will print a plant project very easily with using both the animal and plant tissues.

a cow head

azeem.hussein Wrote:
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> With all of the talk about printing cells and
> tissues... I'd like to start a thread where we can
> really take a look into the issues of printing
> cells, for both animals AND plants. Furthermore,
> what about printing microalgae, etc? My first
> Mendel has yet to arrive, but I've got an
> educational background in biomedical engineering,
> and would be glad to help spearhead and hopefully
> begin such a project...
>
Vegetal cells? That 's exciting!

I am new in this area. However, here is some challenges I look forward.
Symbiotic system. Putting vegetal, animal and human cells together and letting them grow together. Possible in combination with other materials e.g. inorganic, nano or super materials in order to create an encapsulate module/system.

New shaped/extranatural tissues. Experiment ways to stimulate cells to change shape in order to enable them to deliver two functions e.g. acting as a muscle with self vascularisation in one.

Thanks for comments.

George

Edited 1 time(s). Last edit at 01/21/2013 02:43AM by georgep.

azeem.hussein Wrote:
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> Glad to see some response with regards to the
> positioning technology that would give us the
> necessary accuracy. I think the most important
> question now, is how can we extrude the plant
> cell? Typically, plant cells have cellulose, and
> this gives the cell membrane a structural rigidity
> that is not present in animal cells. How can we
> move forward with building an extruder that is
> compatible with cellulose?
It would be interesting with some basic data about cells e.g. diameter. Are they variation between different plant species (in diameter)? Are plant cells capable to tye to eachother, how look a tissue out? Maybe start with a simple shaped tissue.
Which is the "passed" criteria for building that tissue?

... different cells have different sizes around 10 microns - some are as small as 3 microns, others can be as big as 100 microns.

Plant cells develops a hard shell, so loose the ability to move/morph, animal cells have an elastic membrane and can sometime be forced to develop moving abilities.

'Printing' cells isn't enough - you have to construct a surface, they will attract to and settle ... or they will move away and or form local blobs instead of clean surfaces/layers/objects.

An essential option is creating 'supporting' structures, so the tissue is feeded/supported with nutrients.

Maybe even more intersting would be establishing 'communitations' - either nervous cells, and/or methodes for 'programming/reprogramming' and hearding them with hormones and physical/chemical stimuli ...

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Viktor
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Aufruf zum Projekt "Müll-freie Meere" - [reprap.org] -- Deutsche Facebook-Gruppe - [www.facebook.com]

Call for the project "garbage-free seas" - [reprap.org]

Thank you.

VDX Wrote:
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> ... different cells have different sizes around 10
> microns - some are as small as 3 microns, others
> can be as big as 100 microns.
Smaller cells would be easyer to handle in a gel.
>
> Plant cells develops a hard shell, so loose the
> ability to move/morph, animal cells have an
> elastic membrane and can sometime be forced to
> develop moving abilities.
>
> 'Printing' cells isn't enough - you have to
> construct a surface, they will attract to and
> settle ... or they will move away and or form
> local blobs instead of clean
> surfaces/layers/objects.
That's correct. Appropriate support was implied.
>
> An essential option is creating 'supporting'
> structures, so the tissue is feeded/supported with
> nutrients.
Kind of compact bioreactor.
>
> Maybe even more intersting would be establishing
> 'communitations' - either nervous cells, and/or
> methodes for 'programming/reprogramming' and
> hearding them with hormones and physical/chemical
> stimuli ...
Hormones would be what I should call for "bus data" adressing several receive terminals.

It should be different primary tissue "templates" to separate some task and try to solve it.

George

Edited 2 time(s). Last edit at 01/21/2013 11:10AM by georgep.