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Overview A researcher from China has been
looking for an in vitro platform to
run cancer cell migration assays. He found that AIM 3D Cell Culture Chips are
suitable for his application as the chips offer useful features such as the
ability to monitor live cell migration. However, he faced a problem in filling
medium into the media channels without leakage, after filling the gel channel
with Matrigel. After a discussion, we realized that
the underlying reason could be the concentration of the Matrigel
that was used. We advised him to use Matrigel without
dilution, and to try another batch of Matrigel if the
first option fails. In the end, he successfully solved this problem by using a
higher concentration of Matrigel and by controlling
injection pressure during the gel filling step. Background The researcher is interested in
using AIM chips for cell migration assays where cancer cells seeded into the
media channels can be observed invading into Matrigel.
He likes the fact that he can observe and quantify the cell migration process without
any ambiguity. However, after filling the gel channel with Matrigel,
50% of the AIM chips failed when he injected medium into media channels. He
noticed that medium would leak from one media channel into another channel. In
some cases, the medium would pass through the Matrigel
and leak out from gel inlets. This could indicate gel disruption. In addition, bubbles
were trapped inside the Matrigel during gel filling. This
problem still occurred occasionally, even though he was careful to make sure the
Matrigel solution was bubble-free. Solution The researcher had diluted the Matrigel with medium in a 1:1 ratio to a concentration of 4
-8 mg/ml. Based on feedback from other users who use Matrigel
to construct 3D matrixes, Matrigel should be used
undiluted and preferably in the range of 10 -12 mg/ml. The researcher further
confirmed that he was able to prevent the leakage of medium by increasing the
concentration of Matrigel. Besides, he also found
that a slower gel filling rate* would help to solve this problem too. In
the discussion with the researcher, we also realized that he did not change the
pipette tip between each gel filling step as he was concerned that Matrigel would polymerize quickly if he did not complete
the filling process as soon as he could. Due to the high viscosity of Matrigel, there is usually some leftover gel in the pipette
tip after every gel filling step. This will create air bubbles in the subsequent
gel filling step if the same pipette tip is reused. Therefore, we recommend
using a fresh pipette tip to fill each new gel channel. *Fast
or slow is a subjective term, you may need to optimize the filling step for
your application. Matrigel may polymerize and block
the gel channel during the gel filling step if the filling process is too slow. Conclusion Matrigel can be
tricky to work with as it is viscous and it polymerizes very quickly at room
temperature (you may find this
article helpful in handling Matrigel).
For the application of Matrigel in AIM chips, we
recommend using Matrigel undiluted and preferably
within the range of 10 -12 mg/ml. Gel filling rate should be optimized for your
application. We recommend using a fresh pipette tip to fill each new gel
channel to prevent bubbles from being trapped within the channel. Lastly,
we would like to thank the researcher for sharing his experience with us and we
believe that this is going to benefit many others in the community!
-Sei Hien-
Applications Development Scientist |
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