UPDATE: Somewhat embarrassingly, and fortuitously, I hadn't researched enough ferrule suppliers before making this post. After contacting a couple more, I found a supplier that sells 230 μm ID ferrules for $1.5 / pc. It is the Shenzhen Han Xin Hardware Mold Co. They do not have the 230 μm ID ferrules listed on their Alibaba page, but you can contact them for a custom order. Our lab ordered a set of 10 from them, and they worked well. If you use a lot of ferrules, I suggest ordering a test set yourself (shipping is $50).
If you want an American supplier, you can use Kientec. They sell 225 uμm ferrules (FZI-LC-225) for $3.25 / pc with an order of 100. These ferrules fit the fibre a little more snugly.
(The below is now outdated.)
Tl;dr: I am trying to get a bunch of labs to pool money to get create a new source for 230 μm ferrules.
The Palmiter lab makes its own fibre optic cannulae for implantation, using the protocol described in Sparta and Stuber. This has saved us a lot of money, making each cannula cost less than $10. As we have ramped up our optogentics, however, the monthly cost has risen enough that I wanted to find a way to save more money. The biggest cost in cannula construction is the zirconia ferrule (1.25 mm OD, 230 μm ID) we use, which cost $5 a piece. This is in contrast to ferrules with smaller 100 μm bores, which cost $1 a piece.
After hearing about Alibaba in the news, I looked there, and found lots of manufacturers for 100 μm ID ferrules, but none for 230 μm ID ferrules. Curious, I contacted Huangshi Sunshine Photoelectric, Co. to see if they could make 230 μm ID ferrules. They responded that they could, but that they would have to make a new "model." Making the new model would entail a one-time fixed cost of $7500, but once the model is made, the ferrules will cost $0.95 / piece for orders of 1000. (I sent them the specs of the Precision Fiber ferrules. They recommended a slight reduction of the diameter of the epoxy concavity, from 0.9 to 0.8mm; otherwise they should be the same. Once we have the money, they will make a confirmation diagram.)
I would like to get a group of labs together to cover the cost of the $7500 model (labs at UW should be able to cover $1500). Once the model is made, if your lab is big enough, you will be able to order directly for Sunshine Photoelectric in batches of 1000. If you can't use that many, the Palmiter lab should be able to pool together a bunch of smaller orders, and then distribute them.
If your lab uses these ferrules, and would be interested in contributing to getting the model made, please e-mail me at map222 at uw.edu.
UPDATE: The Zweifel lab here is on board, so we only need $6000 more!