Re: [DIYbio] Re: DIY Biorreactor at Nature Biotechnology

On 07/20/2018 01:13 PM, Jonathan Cline wrote:
> "LED/photodiode sensor pairs perform OD900 readings." Biofilm, condensation, etc will obscure the optics.

How do you know that? They probably stir often enough to avoid condensation problems and
their code probably keeps track of when bio-film is starting and ask for a
transfer of contents to a clear bioreactor tube and sleeve.

It's all very efficient as soon as it saves a person from having to do inhuman tasks on
an hourly basis 24x7.

Sleeves are just suggestions. They say their aim is to promote using 3DP for custom
sleeves. A custom sleeve could be made
with lots of insulation for incubation without big power draws.

By the time it gets to be stacks of 16 sleeve modules 10 high 2 deep with an aisle
between, there will be some evolution to take care of your concerns.

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[DIYbio] Re: DIY Biorreactor at Nature Biotechnology

Great paper, some skepticism is in order.  

Not sure how this differs from similar systems prototyped at MIT in ~2005 (which were abandoned as dead-ends, I believe).

"Thermistors and heaters attached to a machined aluminum tube" with given (and very ideal looking) graph of temp oscillation 30C-40C over 14 hrs vs. room temp with period 30 mins, for a culture in "40 mL autoclavable borosilicate glass vials".  The heating system seems questionable.  No active cooling (except if provided by fan, which also operates for stirring).

"the hardware design enables rapid, cost-effective scaling and customization"  The design certainly is not cost-effective.   "Individual sleeves cost ~$25".  In terms of scalability, it is not scalable, N cultures must scale with N hardware devices (appears to be 16), N pumps, N flow tubes, etc.  (All flow tubes needing replacement.)  N is further reduced (divided by constant X) for the biofilm elimination protocol. The concept to "monitor hundreds of cultures in real time" will require some M arduino's which also scale linearly.  Power requirements will create problems once N > some small number. 

"With daily replacement of used vials, four Smart Sleeves could be used to passage a culture, biofilm-free, for an indefinite period of time"  ... which means a minimum run-time cost of $x*(N-y) per day.   (Some part of that cost may be reduced by autoclaving, better if the design used more glass)

"LED/photodiode sensor pairs perform OD900 readings." Biofilm, condensation, etc will obscure the optics.

The interesting part of the paper is the "Millifluidic device w/ integrated pneumatic valves"  (approx 14 cm in size) "by adhering a silicone rubber membrane between two clear sheets of laser-etched plastic, each patterned with desired channel geometries and aligned" "that overcomes biofilm formation during long-term continuous growth experiments" ...  yet that device is not detailed in this paper.  No discussion of where the pneumatics is sourced from.  The device is perhaps these papers from 2000 and 2003, which are not novel in 2018,   1) Unger, M.A., Chou, H.P., Thorsen, T., Scherer, A. & Quake, S.R. Monolithic microfabricated valves and pumps by multilayer soft lithography. Science 288, 113–116 (2000);  2) Grover, W. H., Skelley, A. M., Liu, C. N., Lagally, E. T. & Mathies, R. A. Monolithic membrane valves and diaphragm pumps for practical large-scale integration into glass microfluidic devices. Sensors Actuators, B Chem. 89, 315–323 (2003).





No mechanism for reading pH. 



On Thursday, July 12, 2018 at 9:50:12 AM UTC-7, Markos wrote:
https://www.nature.com/articles/nbt.4151



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