Saturday, November 10, 2012

More On Petaka Mini Bioreactors

Getting Culture Conditions Right Every Time

I would like to provide yet more information on the capabilties of our new and innovative Petaka Mini Bioreactors. This posting focuses how oxygen concentrations are tightly controlled in a way that is consistent with the cultured cells natural environment.

The length and cross-section of the respiratory duct is purposely engineered to partially restrict the diffusion of oxygen from the high levels of ambient air to create lower, physiologic levels of dissolved oxygen in the reaction chamber. In accordance to Fick’s Law, as oxygen is consumed inside the culture chamber, decreasing the partial pressure of oxygen in the media, oxygen diffuses in from the outside atmospheric (higher) partial pressure, through the respiratory duct, to the lower partial pressure inside. Diffusion is proportional to the concentration gradient, as regulated by the engineered design of the respiratory duct, and occurs entirely spontaneously and without any manual intervention whatsoever.

Image: Petaka®G3 Ducted Respiratory Chamber (DRC). (1) cell culture chamber;(2) injection port; (3) respiratory duct; (4) 0.2μ filter; (5) water vapor condensers and capillary breakers; (6) unique barcode. The DRC is shown upright in a silicone stand (7).

At the same time, the respiratory duct partially retains carbon dioxide from cellular metabolism to maintain a physiologically normal mild acidosis to balance pH. All gas exchange with the outside environment occurs via a 0.2 micron filtered vent, preserving the internal sterility of the device but allowing exchange of gas diffusion and flow to prevent pressurization issues when filling and emptying the bioreactors.
Therefore, cell culture in DRC’s/Petaka G3 does not require supplemental oxygen-nitrogen balancing, CO2 and humidity sources, eliminating the entire panoply of gas tanks, regulators, sensors, microprocessors and water pans. This creates a double benefit: not only are cells cultured in more normal physiologic conditions, but the mechanics, logistics, risks and costs of cell culture are greatly simplified and reduced.

The Results are Stunning!

Here are result using Petaka® G3 LOT for culturing our UCB Derived hMSCs and Mouse MSCs.
Images: (A) Immuno-fluorescence microscopy of a mouse MSC in differentiation progression. Culture under 20 mmHg of O2 partial pressure. Red fluorescence positive staining of GFAP. hMSC 3 hours after seeding in Petaka G3 with low serum media and without matrix (B) and 96 h later (C). Photos: Jim Musick. Vitro-Biopharma. September, 2012.

Next up using Petaka DRCs for GMP. Stay tuned.

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