HistoEnder: A 3D printer-based histological slide autostainer | Hacker News Reader

HistoEnder: A 3D printer-based histological slide autostainer

github.com

52 pointsyread8 comments

So some background here for those who don't spend their days in tissue labs: tissues are sectioned in very thin (~5um) slices and put onto slides. At this point, they are uncolored. In order to see any tissue structures, you have to apply a stain to the slice. This is done by loading slides into a holder and dipping them into a series of different liquids. All stains have their own recipes, but it's not unusual to have something like this:

1. 5 minutes in distilled water 2. 2x 5 minutes in 70% ethanol 3. 5 minutes in 90% ethanol 4. 5 minutes in 100% ethanol 5. 10 minutes in stain #1 6. 3x dip in 100% ethanol 7. 10 minutes in stain #2 etc

so what labs usually have if they don't have an automated stainer is a long section of benchtop with a line of small glass or plastic buckets (kind of like small tupperware containers), each with a different fluid. The tech then uses a set of timers to move the slide holders from one to the other according to whatever recipe they're following. It's honestly not a terribly time-consuming process, you can do a lot of other stuff while you're in a five minute wash, and a little variability doesn't matter much (like if you're in a bucket for 5:10 instead of 5).

That all being said, an automated stainer is a super nice thing to have, because you get 40 minutes uninterrupted time to do other things instead of having to go move things around every couple of minutes. So a couple of hundred dollars for this 3d printer one might be really worth it!

This is cool. I frequently find that medical people (at least in America) are intentionally ambivalent towards how much things cost - charitably, for patient care at least, you want the highest quality care for everyone, and skimping on cost could compromise someone's health. The idea that something being more expensive makes it more scarce, as obvious as it would seem, is often a secondary consideration.

Example: My wife is in surgery, and has told me how surgical tools often come billed as a set. Rather than being able to bill for a single tool, if an operation requires another duplicate of the same tool the surgeon will often just open an entire new set.

Another example: In college I build a tDCS machine [1] for about $20. I knew a doctor from the VA who was working in the area who showed me one with essentially the same circuit which sold for $80,000 - essentially for the stamp of approval from the FDA to use it in a clinical research setting.

There are reasonable-sounding explanations for both things I guess, but the obvious consequence is that the number of people able to receive care is dramatically lower. I feel like there are probably similar analogies in technology, but maybe they are more easily disrupted because of lower regulatory barriers.

[1] https://www.hopkinsmedicine.org/psychiatry/specialty_areas/b...

"Example: My wife is in surgery, and has told me how surgical tools often come billed as a set. Rather than being able to bill for a single tool, if an operation requires another duplicate of the same tool the surgeon will often just open an entire new set." That could be because the instrument required has been sterilised as part of a set and is not sterilised individually. This is a common problem in the UK where I work (as a surgeon), - the logistics of individually tracking all single packaged instruments would be unworkable and hugely costly.So they are grouped as a set for a particular operation.

Yeah I think that's why in the US as well, but I think it reflects a lack of sense of urgency for figuring out how to do it more cheaply. Compared to hospitals in Vietnam, for example, where sanitization standards are much lower, they do a lot more creative stuff to save on costs. It leads to worse outcomes, of course, but if they insisted on the highest quality care for everyone then a lot fewer people would get care in the first place

Are we talking about metal instruments that are later resterilized and reused? How much waste does this create, finnancially and in terms of material?

Yes, surgical tool sets are often reusable after resterilization. But there is also a large volume of single-use products.

I'd love to see a video of this in action.

A Youtube search for "HistoEnder" returned a single useful result:

https://www.youtube.com/watch?v=fK0MTESW2LU

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