[NEW SENSOR] Who is interested in an OD probe?

Hardware, PWM, and Optics
1

My Team and I have developed an alternative method to measure OD for our custom bioreactor, and it works with the Pioreactor control system through the i2C port.

The following are the shortcomings of the current stock Pioreactor OD system:

  1. It limits the diameter of the reactor chamber to allow measuring OD through the vial wall. Therefore, limiting the max volume of the pioreactor vessel.
  2. Small linear density range prevents high-density experiments. From the forum, the highest reported OD was 10 using the 45-degree scatter port. This is roughly a max of 5g/L for Ecoli, 2.5g/L for yeast, and 1.5g/L for spirulina.
  3. Any rotation in the vial’s position affects the OD readings

With our top-mounted probe design, the reactor volume limit is eliminated. Our sensor design methodology should be able to measure up to 200g/L, but we are in the process of validating this claim.

While this type of sensor already exists in industry, used models sell for 2500USD on eBay. They are also much bulkier than our design, making them unfit for stock Pioreactors. Offered by Mettler Toledo and Hamilton.

What we can offer:
If there is enough of a demand for this sensor, we are considering selling it. It will work with your current Pioreactor setups. Whether you want to use it with the 20mL vial or an 80L reactor, like we do.

What we are working on currently before bringing it to market:

  1. Probe will be made out of materials that can be autoclaved
  2. It will run an automated calibration script to convert the OD readings to biomass density in g/L. This is done by running calibrated dilution at a constant rate using a know density culture or calibration media and monitoring response to fit a linear relationship
  3. Further adapting the Kalman filter to the probe. Potentially removing the need to disable stirring, aeration, or LEDs (for PBRs) to take measurements
  4. We are in talks with suppliers to get user ready components for the complete probe

As you may have guessed, this has taken months of development and still requires some time. Our goal is to make this an affordable solution, essentially unlocking this otherwise priced out sensor. We do not yet have a final price for the sensor but it will be at a fraction of the currently available options.

Prior to proceeding in the development required to make this a user ready sensor, we need to gauge interest of the community. Please let me know if this is something you need.

Rafik

4 Likes
2

Yes! We’re looking to buy from Hamilton but if this sensor were already integrated nicely into pioreactor and were cheaper then we’d definitely consider. We plan to have an array of about 10 2L reactors

1 Like
3

I’ll shoot you a message abt probe preference.

4

I would love to know more. I have an undergraduate who is working on building a larger reactor with more probes as a senior thesis project.

5

For the custom reactors, I need to know 2 things ahead of time:

  1. What probe length do you require? This will depend on how much headspace you have in the reactor. The probe needs to sit at least 1 cm below the media level. If you are aerating the reactor and disable aeration, it will need to be the headspace height when air is disabled.
  2. What mounting option do you prefer for the top of the reactor? A common one is PG13.5 mounts; however, there are many options. A good compromise would be having a standard size and providing adapter files that you could print with autoclavable materials.

While any size and mounting system can be ordered, it will reduce the final cost if there is a standard size that can work for many reactors.

I am currently ordering different samples that will have an M6 thread that mounts to the top plate and a needle probe ranging in diameter between 2-3mm and different lengths from 5-9cm.

Please let me know if you have any questions or specific asks regarding the probe.

6

Yes interested, also interested in pH and DO.

7

This is amazing!!! Thanks for sharing, we would be intrested aswell!

8

I am interested in this as well.