1. Automating the Cell Culture Sampling Process
Mike Phipps
Tara Ryan
BME 273
March 18, 2002

2. Problem/Background
Cell cultures maintained in bioreactors for Research and Development purposes in pharmaceutical companies must be sampled regularly
Samples (10-15mL) are typically taken once most days, and twice every three days or so when the culture is split
methods of manually withdrawing a sample from the bioreactor can be reliable but still come with risks of culture contamination
lab workers must be trained and experienced in sterile technique

3. Existing Sampling Methods

4. Existing Sampling Methods

5. Flowchart of the Sampling Process
Make sure tip is okay to enter culture
Ensure sterility of syringe tip
Obtain new syringe
Draw sample from culture
Insert syringe tip into culture
Dispose of used syringe
Pull sample into syringe tube
Remove syringe tip from culture
Move collecting tube to analysis machines
Deposit sample into collecting tube
Move syringe to collecting tube

6. Project Goals
reduce the risk of contamination that occurs due to sampling
reduce the time it takes a lab worker to draw a sample from a culture
reduce the skill and training required by a lab worker

7. Design Ideas
Idea #1
Continuous flow of medium and cells through tubing loop
switch 3-way valve to the sampling line in order to draw a sample
simple
does not avoid the traditional syringe switch

8. Assessment of Design Idea #1
simple
inexpensive
easy setup
Advantages:
Disadvantages:
does not avoid the “syringe switch”
does not reduce the time or labor needed to sample

9. Design Ideas
Idea #2
Ethanol and wash sterilize the syringe tip (needle)
Use of septa
Expand to a set of 4 bioreactors

10. Assessment of Design Idea #2
Advantages:
Disadvantages:
Very little risk of contamination
Can enclose/sample many bioreactors
Reduces the labor/time needed to sample
Ethanol and wash supplies must be changed frequently
Expensive
Chance of alcohol residue on syringe tip (can kill cells and influence viability counts)

11. Design Ideas Idea #3 Open flame sterilizes the syringe tip (needle)
Use of septa
Water-gasket bioreactor system for better maintenance of the culture’s temperature
Expand to a set of 4 bioreactors

12. Assessment of Design Idea #3
Advantages:
Disadvantages:
Very little risk of contamination
Can enclose/sample many bioreactors
Reduces the labor/time needed to sample
Once cooled, syringe tip is safe to enter the culture (you can calculate how long the tip needs to cool off after submergence in the flame, but in #2, there is no easy way of making sure all the alcohol wash is gone)
Expensive
Heat from flame may influence temperature of hood environment or of culture
No flammable materials/chemicals should be in the hood

13. Design Ideas Idea #4 Simpler (fewer steps for mechanical arm)
Reliance on hood to provide sterility
Expand to a set of 4 bioreactors

14. Assessment of Design Idea #4
Advantages:
Disadvantages:
Reduces the risk of contamination
Can enclose/sample many bioreactors
Reduce the labor/time needed to sample
The hood air source only blowing when the door flap is open
Expensive
Reservoir of new syringes is briefly exposed to outside environment each time a sample is transferred to a collecting tube

15. Conveyor Belt Idea
Conveyor belt would transport multiple bioreactors to a stationary mechanical arm so that arm will not require a track along which it can move
Cost of a 12-feet long conveyor belt with a diameter/width of 30 inches is estimated to be $6000*
Air inlets (nitrogen, oxygen, etc.) come from pipes running down from the ceiling; can’t easily move these with the bioreactor
* according to

16. Final Design Advantages: Disadvantages:
Combination of Design Ideas #3 and #4 (uses flame sterilization with the movable door feature)
Advantages:
Disadvantages:
Reduces the risk of contamination
Can enclose/sample many bioreactors
Reduce the labor/time needed to sample
The hood air source only blowing when the door flap is open
Once cooled, syringe tip is safe to enter the culture (you can calculate how long the tip needs to cool off after submergence in the flame, but in #2, there is no easy way of making sure all the alcohol wash is gone)
Heat from flame may influence temperature of hood environment or of culture
No flammable materials/chemicals should be in the hood
Reservoir of new syringes is briefly exposed to outside environment each time a sample is transferred to a collecting tube

17. Current Work Components of the Device:
test tubes, test tube rack, disposable syringes, syringe disposal bag, bioreactor system(s) with septa embedded in top, hood device with movable divider, mechanical arm, track, air purifier, Bunsen burner, natural gas line
Determine the manufacturers, material composition, price, dimensions, and weight of each component

18. Future Work
Calculations (heat transfers, air flows, etc.) and research of parts manufacturers to determine specifications of the final design
Draw final design using AutoCAD
Production of a prototype?

19. References ABEC Website, <http://www.abec.com>
B. Braun Biotech Website, <
Bailey, James E., and Ollis, David F. Biochemical Engineering Fundamentals. McGraw-Hill Inc.: St. Louis, 1986.
Balcarcel, R. Robert. Associate Professor of Chemical Engineering, Vanderbilt University.
New Brunswick Scientific Website, <
Todar, Kenneth. “The Control of Microbial Growth.” 21 September 2000 <