Bubble-free cell culture

Creation of bubble-free cell culture environment in PMMA microfluidic chip with polymeric tape channels

In a previous study, we have found a good way to eliminate bubble during culturing in PMMA microfluidic chip with polymeric tape as microfluidic channels.

The results are described in detail in the supplementary information of our previous paper.

10.1063/1.4749826

In short, the microstructures from the CO2 laser processing may allow bubbles to trap around the bubble wall.

In cell culture experiments, if small bubbles are not removed first, it is a interface that can allow the gas dissolved in the culture medium to deposit at the interface and the bubble grows and eventually blocks the channel and cause cell death.

The solution we have found is that by pre-treating the assembled microfluidic chip in a low vacuum, prompting the chip to better bond together. Afterward, the tubings are attached and a pure CO2 gas is passed through the system. Since the CO2 is more dissolvable in the solution, even if there are some small bubbles trapped on the defects on the channel wall, it will be able to dissolve in the system. 

The bubble free cell culture environment in PMMA microfluidic chip allows long term (up to months) of feasible cell culture on chip.

Creation of bubble-free cell culture environment in PDMS microfluidic chip

There are several ways to remove bubbles in PDMS microfluidic chip.
1. since PDMS is air-permeable, one way is to pressurize the fluid in a blind-ended channel to force the air into the PDMS and escape.
This technique is commonly used by people doing PDMS microvalve technology.

2. the PDMS is hydrophobic, to remove the bubble, one can use 99.5% ethanol to prewet the system , the bubbles can be removed very easily. afterward, ddH2O can be filled in the system, and so on culture medium.


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