Petaka G3 Frequently Asked Questions
Why must I hold the Petaka G3™ upright when filling with medium?
The restrictive respiratory microchannel in the Petaka G3™ provides physiological oxygen levels while simultaneously maintaining ideal CO2 and pH levels for your culture. However, this delicate balance of inward and outward gas diffusion is not optimal when the microchannel is filled with medium. To avoid this from happening, simply hold the Petaka G3™ upright when filling (see Fig. 1). The air path from the culture chamber to the gas microchannel is on the upper right corner of the Petaka, near the silicone injection port.
At what level of dissolved oxygen will the Petaka G3™ maintain my cultures?
The proprietary microchannel regulator within each Petaka G3™ will reduce the dissolved oxygen from hyperoxic levels (150mmHg pO2) to levels found in native tissues (20-50 mmHg pO2). The exact level of dissolved oxygen will vary depending on cell type, length of uninterrupted culture and medium conditions, but will at all times be determined by the needs of the cells. It is important to understand that oxygen flow into the Petaka G3™ is controlled by diffusion, so the bigger the difference between the outside air and the inside culture chamber, the more oxygen will diffuse in.&n
What types of cells can I culture in the Petaka G3™?
Practically every cell type has been successfully cultivated in the Petaka G3™, including attached, suspension, immortal, primary and transfected cells, hybridomas, MSCs, ESCs, iPSCs, etc. The Petaka G3™ FLAT is untreated for suspension cell culture while the Petaka G3™ LOT is surface treated for attached cell culture.
How is it possible to grow cells in the Petaka G3™ without supplemental CO2?
Cells naturally generate CO2. However, in plates, dishes and flasks this CO2 rapidly diffuses out of the medium, so a closed CO2 incubator system is required. The Petaka G3™ automatically retains CO2 at a level sufficient to maintain pH in a standard bicarbonate-buffered medium. However, a minimum number of cells in the starting culture must be present to supply sufficient CO2 to maintain this pH balance. Decades of experience has led Celartia to recommend at least two-million cells (25,000 cells/cm2) be seeded in a Petaka G3™ when culturing without supplemental CO2.
How do I perform long-term microscopy with the Petaka G3™?
Because the Petaka G3™ provides a unique, closed, gas-controlled culture environment without significant evaporation, it acts like a mini-incubator all by itself. Because of this, specialty cell culture and experimental processes may be performed for long periods of time outside of the standard CO2 incubator environment. This is impossible with plates, dishes, flasks or bags since medium will evaporate leading to loss of osmolarity and the dissolved CO2 will rapidly be lost resulting in cell death.
How do I preserve cells at ambient temperature in the Petaka G3™?
One of the amazing features of the Petaka G3™ is its ability to preserve cells at room temperature for extended periods of time. Many labs use the Petaka G3™ to eliminate cryopreservation for processes that benefit from cell storage for up to 2-weeks. When cells are maintained at low dissolved oxygen, ideal pH levels, and ambient temperature (15-23°C), cells simply go dormant, pausing their cell division and reducing their metabolic rate significantly.
How do I cryopreserve cells in a monolayer in the Petaka G3™, and why is it superior to standard freezing in cryovials?
Petaka G3™ is the only cell culture device that also allows for convenient and direct cryopreservation inside the primary culture device. Cryo vials feature a low surface-to-volume ratio. This means that the operator must use a slow freezing process while the glass transition progresses from the outside to the center of the vial. During this slow freezing period ice crystals may form inside of cells and damage them, leading to poor post-thaw viability. A preferred method is thin-film cryopreservation, only possible in the Petaka G3™.
How is it possible to wash and centrifuge cells without transfer to conical tubes?
The Petaka G3™ is the only cell culture device that can be centrifuged directly. This allows the user to pellet, wash and separate cells without any transfers into conical tubes. Unlike open dishes, plates, and flasks, the Petaka G3™ is designed and manufactured to withstand up to 650g during routine centrifugation. So, instead of aspirating and transferring cells for centrifugation, the user can simply place the Petaka G3™ into the centrifuge and spin directly. This results in a cell pellet in the bottom corner of the Petaka G3™.
What do the colored ports on the Petaka G3™ indicate?
The Petaka G3™ LOT for adherent cells features a blue silicone injection port. The Petaka G3™ FLAT for suspension cells features a white silicone injection port. The orange color port on the Petaka G3™ HOT is for when you want slightly higher oxygen tension in your cultures.
Should I culture with the Petaka G3™ in an upright or horizontal configuration?
Suspension cells must be cultured in the Petaka G3™ in a horizontal configuration, similar to a flask because these cells will clump on the bottom when the Petaka G3™ is cultured upright. After adherent cells attach, (typically 1-2 hours), the Petaka G3™ may be left in the horizontal position or it may be switched to an upright position for the duration of the culture.
How can I measure the amount of dissolved oxygen inside my Petaka G3™?
The Petaka G3™ is unique in that it is now possible to measure the dissolved oxygen (pO2) in your culture in real time, using a sterilize, off-the-shelf setup. The Petaka G3™ DO Sense features an oxygen sensing dot manufactured by Ocean Insights, that when paired with the NeoFox™ reader, allows the user to measure and record the dissolved oxygen in the culture medium with precision and high temporal resolution. With the Petaka G3™ DO Sense it is easy to perform simple bioprocess monitoring or to carry out sophisticated experiments determining single cell oxygen consumption rates.
How is it possible to eliminate the water tray from my incubator?
Standard plates, dishes and flasks must be open to allow open CO2 gas exchange. The Petaka G3™ is functionally closed and retains CO2 in culture automatically. All liquid transfers are performed through a closed, sterile silicone port. In addition to benefit of reduced contamination risk during processing, the closed design means that media evaporation is practically eliminated. This is why there is no need to maintain a water tray inside the incubator. This eliminates a second major contamination source.
What are the basic features of the Petaka G3™?
• Class VI medical grade resin
• Optically clear polystyrene growth surface
• Sterile (SAL 10-6)
• Standard SBS footprint
• 0.2μm PTFE air filter
• 24ml filling volume
• 95kPa tested
• Free of detectable endotoxin
• Sterile silicone port access
• 75cm2 surface (one-sided culture)
• 150cm2 surface (double-sided culture)
• Functionally closed processing
• Practically no media loss due to evaporation
• Single-use disposable