Development of microvasculature mimetic device

ByTejas Khire

From last few months, I am working on the development of a co-culturing system that can work as an in vitro mimetic of the human vasculature. The idea is to make a device capable of co-culturing, real time imaging, equipped with fluidics for testing different assays as well as to grow cells under shear. TEER measurement is another feature, which will help us in monitoring the formation of a tight endothelial monolayer, and allow us to manipulate the physiology of endothelium. I aimed for using sepcon chips in this device to make its manufacturing less expensive. In my first attempt, I made the entire device out of PDMS gaskets, making the assembly an irreversible process. It is sleek and looks sharp, but reproducibility is trickier.

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So I tried to redesign the assembly so that I can have maximum detachable components and the task of assembly is least cumbersome. I used polycarbonate blocks to act as a top and bottom support. And instead of doing a permanent UV-Ozone bonding, and PDMS bonding, I decided to do a simple clamping of the membrane to separate top and bottom chambers. Assembly is held together by nut and bolts.

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The electrodes are made of aluminum tape connected to ITO that is deposited on the glass slides.

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The two darker marks on the edges is 250 nm thick ITO, deposited at 40 C and then baked in tube furnace at 500 C for another 1 hour.

To test the functioning of the device, I filled the device with 1x PBS, and took the TEER measurement. Then I flushed with DI water, and then back with PBS and noted the TEER values for each case. As shown in the images, TEER rises while switching from PBS to DI water, and then drops back when filled with PBS again.

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The TEER value for PBS is not completely zero, in fact was continuously fluctuating and changing. The baseline excess of TEER could be due to insufficient coating of the ITO on the glass slide and/or the aluminum tape connections. I need to somehow make the electrode connections more robust. But this is a good place to start nonetheless.

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