Optimization of our isolation technique using Beads
Hello Everyone,
I have been working on 100 and 50 nm beads since ACNMM conference to optimize our isolation technique for exosomes and verify that our approach works.
Technically, based on the discussion that we had before about Peclet Number, in order to decrease this number, I have been running all my experiments with 1 microliter/min as the flow rate. Basically, i was trying to go through all the steps of our technique including Trapping stage, cleaning stage, releasing stage.
- Nanoporous Membranes:
So I had a lot of problems with the breaking of these membranes and air bubbles in the channels, especially with this flow rate. Air bubbles were available mostly when I was shifting from one stage to another one which needs changing of the syringe for instance from the beads solution to PBS solution for cleaning stage.
In the washing stage: the idea of washing step was to wash away all the remaining or undesired particles, or in these experiments to wash away beads that are still floating in the channel and during the cleaning stage, I kept the flow rate constant to keep the transmembrane pressure constant.
So according to images and average intensity of the same area of the membrane in different stages, we can successfully trap particles, and release them, although I need to repeat my experiments.
- TE membranes:
In the second part, Tom asked me to do my experiments using TE membrane to verify our approach and to show advantageous of using Nanomembranes using Track Etched membranes.
So the first challenge for shifting from nanomembranes to TE membranes was the design of our microfluidic devices because of limitations with TE membranes for imaging, so Henry and I came up with a new design and at the same time, we decided to shift to clampable devices, and in this design we have the membrane upside down.
Another challenge is the wrinkling of the TE membranes which can make the imaging a little hard.
Attached please you can find all the results in the powerpoint.