Since there are a lot of steps in preparing liver tissue for TEM, it is difficult to say where you might be going wrong without more information about the protocol you are using.

I would first check that you are using the proper fixative. I use 2.5% glutaraldehyde buffered with a cacodylate-sucrose solution (0.1 mol L-1 sodium cacodylate and 0.1 mol L-1 sucrose, pH 7.6) and then fix at 4°C.

For the processing, I stain with 1% OsO4 first and then with 0.5% uranyl acetate followed by ethanol dehydration, proplyene oxide and embedding. There are wash steps in between of course, I use 0.1N acetate buffer. This protocol works well for me but there are other very good ones out there too. If you are able to find this book, then I recommend it highly: https://www.springer.com/gp/book/9780306477492

- Melissa