This is a holder/incubator for fresh sectioned tissue designed to fit a 300mL beaker that is approximately 73mm in internal diameter. 

In patch-clamp electrophysiology it is imperative that the cells (namely neurons) within the tissue sections remain alive. To achieve this, the tissue sections need to be incubated in an artificial cerebrospinal fluid that is continuously infused with oxygen via an aerator stone.

This is my response to people using cut up 15mL conical tubes, culture dishes with the bottoms removed, and nylon mesh all held together by parafilm to hold and aerate their live tissue sections. It works but is definitely janky and is not stable and also does not take full advantage of the available space of the beaker.

Commercial solutions exist but are insanely expensive (upwards of $500 for a single unit)

My design improves on all aspects of this idea:

1. The ring is friction fit to the body of the holder and is meant to hold a piece of nylon mesh stretched out across the unit to suspend the tissue slices in the solution. 
2. Can take advantage of nearly the full diameter of the beaker to be able to hold more slices without overlapping. 
3. The tube allows the insertion of a bubbler stone connected to an oxygen supply and forces the bubbles to move up through the tube and flow out and over the brain slices giving them a continuous supply of O2. 
4. The facets at the top of the tube help to break up larger bubbles before they flow down to help with the gas exchange
5. COST: This solution uses very little filament and costs about $1-3 to make depending on your print settings. 

You will need to use supports to print the holder itself; I've also found that if the nylon mesh wants to contract while stretched out over the holder, a couple dabs of CA glue on the edges are enough to hold it in place.

Enjoy!