Practical uses of 3D printing in an electrophysiology lab

I have mentioned before about my 3D printer, and how useful I have found it. Today, I’ll explain some of the practical uses I’ve found for 3D printing for electrophysiology. The point is that electrophysiology equipment is both extortionately expensive and annoyingly non-compatible. So, it is often quicker, cheaper and easier to design and print a “thing” than try to buy something to fit your particular need.

Build-a-bath workshop

A year or two ago, I was setting up our third (at the time unused) rig for calcium imaging. We had various bits of baths, but no complete set. And it would cost a (relatively) large sum of money to buy a replacement. I found that what I was missing was the “bath” bit (I had the holder). So I measured up one of our existing ones and designed a reasonable copy in Autocad:

3D design for an electrophysiology bath insert.

My printer was able to make it with a very smooth base, which is the crucial aspect for obtaining a watertight seal. I installed it on the calcium imaging rig, it worked well, and is still in use there to this day. Oh, and for anyone who’s interested, I have made the 3D design available on Thingiverse.

Moving an LED

My loyal readers will know that it was around this time that the light source for the calcium rig died. A replacement LED source would cost anywhere from £3k to £15k, depending on how many colours I wanted access to. However, we had animals ready for experiments at the time, and even if we had the money, it could take weeks for new kit to arrive.

Luckily, we had a blue LED of the correct wavelength attached to one other rigs, that was no longer needed there. I had purchased it to do optogenetic stimulation, but we had switched opto’s to the third rig.

Anyway, this seemed like an easy fix, just swap it over. But of course, it’s never that easy. Because, I wanted to move the LED from an Olympus microscope to a Zeiss. And the manufacturers do not make it easy on the consumer by having common fittings.

So, I measured up the fitting on the LED and the back of the Ziess fluorescence port. I then designed a 2-part “sleeve” that would modify the Zeiss port to resemble the back of an Olympus:

3D design for an Olympus-to-Zeiss microscope fluorescence adapter.

I used cable ties to hold it on tight to the Zeiss fluorescence port. The benefit of cable ties over something more permanent like glue is that they can just be cut off if/when the LED wants changing. The LED now fitted snugly onto the back of the microscope, and, after some fiddling with the data and control connections, was now fully functional for calcium imaging.

A “lab things” service

The main point I want readers to take away from this post is the usefulness of 3D printing for electrophysiology labs. I would strongly recommend anyone reading this who performs a practical skill in the lab like electrophysiology to consider investing in a 3D printer. They are actually quite cheap nowadays (mine was about £250 a few years ago), and I’m sure they’ll save you a lot of time and money in the long run.

In fact, the biggest investment to 3D printing things yourself is the time it takes to learn 3D CAD software and optimising the 3D print process itself. So, if you want something custom making, but would prefer not to have to figure it out yourself, just head over to the Services page and send a request. You never know, I might well be able to save you a lot of time, effort and money.

The CrumbleHopper™

A dietary issue

A colleague approached me a few weeks ago about a laboratory mouse feeder. She was having an issue with one of her experiments; she knew I had done some 3D printing and thought I might be able to provide a solution. Her problem was that she was feeding her mice a special, but very crumbly, diet.

The crumbly diet was making it impossible for her to monitor caloric intake using our currently available food hoppers. Depending on the type of hopper, either the food would crumble all over the cage bottom, or the mice would kick bedding up in with the food and make any accurate food measurement impossible. What she needed was a laboratory mouse feeder that was up to the task.

Designing a mouse feeder

So, my colleague asked me to design and produce a small food hopper that could hold crumbly food without losing it, while still allowing the mice easy access to eat without being able to kick bedding in. It was also important that the hopper be easily added or removed from the cage to allow daily weighing of the food. And as the planned experiment involved some 40-odd animals, they really needed to be low maintenance, and quick and easy to use.

Based on the cages that we have in our animal facility (pretty standard IVC’s from Tecniplast1), I figured the most obvious solution would be to have a hopper that you could hang off the metal grill hopper already present in the cage. Then it would be easily removable as well as being elevated off the floor, and it would be a simple matter to design it to be an easily munchable height from the cage floor.

I “borrowed” a cage from the facility to measure up, and designed what is essentially a hanging basket with hooks. Then after a suggestion from my colleague I made a few variants with different size/shape holes for the mice to access the food:

Initial designs for a laboratory mouse feeder.

Improving the design

I printed these 3 prototypes and gave them to my colleague to test out on the mice. She obviously monitored them very closely, and found that the mice would happily eat from any of them. She did, however, find that the supporting struts were a bit flimsy, so I strengthened those.

Of the three designs, she liked the vertical rectangular slits the best, but wanted the holes slightly wider to allow better access for mouse nom-noms. So, along with a slight adjustment to the height of the hooks to give better attachment, I present the final version of my laboratory mouse feeder, the CrumbleHopper™:

The Crumblehopper: a handy laboratory mouse feeder.

I actually quite enjoyed trying to make these for my colleague, and it does seem to fulfil an otherwise unmet need. So to that end, I am setting myself a couple of goals:

  • To keep an eye open for other experimental situations that could do with having an improved piece of kit. I already have a couple in mind that I am working to produce a solution for.
  • I hope these pieces of lab kit I am developing will be useful to people outside my lab, so to that end I am working towards setting up a small shop on this website to sell the things at a reasonable cost. Where I can, I will also make the designs available online so people with access to 3D printers and such can make them themselves.

Finally, if any of my loyal readers have a niggling problem that could be solved with a relatively straightforward (but otherwise non-existent) solution, please contact me and maybe I can design a solution, as I did for my colleague.


Creative Printing

A few months ago I reached a point with one of my projects where I wanted to house some electronics. A quick Google search showed me that the easiest way, by far, of producing such prototypes would be 3D printing them. Hence I’ve taken my first step towards 3D printing for neuroscience research.

A colleague of mine had produced prints in the past, by sending 3D print files to a third party that printed them for him, for a fee. While this was of course an option, I always prefer to do things myself, so would rather buy a printer and do it in-house, provided the cost wasn’t extortionate. And it turns out the printing technology has advanced far enough that you can get decent quality 3D printers starting from about £250, which was definitely within our budget.

A quick aside here, in case there are any readers unfamiliar with the basics of 3D printing. Everyone will be familiar with “regular” printing; using the example of an inkjet printer, there’s a nozzle that squirts out tiny spots of ink across a sheet of paper to produce the desired pattern. Imagine that instead of ink, the printer is squirting out small blobs of plastic across a flat surface; it then rises up a short distance and prints another layer of plastic, and then up some more and prints another layer, and so on. This lets you produce 3D plastic objects of any shape, with the caveat that each layer needs to stick to something, so you can’t have floating bits.

Where the resolution of a print onto paper is determined by the size of the ink spots and how precisely they can be printed, the resolution of a 3D print is determined by both the size of the blobs (which depends on the size of the nozzle that squirts out the molten plastic), and the precision of placement, particularly with regards to the vertical step size.

What I have described here is classic filament printing; an alternative uses UV-curable resin instead. In this case, the plastic is printed into the desired shape by successive curing of the resin using a UV-light LCD screen. For reasons I won’t go into, resin-based printing methods tend to have better resolution than the filament prints; they are also faster and more reliable. And, as the costs are comparable, I went for a resin-based printer (the Elegoo Mars, which has very good reviews and was supposed to be the best budget printer).

Great, so now that I had a 3D printer, I just needed to print some stuff! Turns out this is the tricky bit, in particular getting to grips with 3D design software. As University staff, I have access to a range of software, including AutoCAD, which is great but also very complex.

After some trial and error, I found that I could make the 3D renders I wanted using basic geometric shapes (mainly cylinders and cuboids), so long as they were aligned and then use merge/subtract functions to produce more complex shapes. See below for the first object I designed – a simple hollow half cylinder for my housing.

3D render of my first custom designed prototype housing.

The next step is to turn the 3D render into a printable format, using “slice” software, which adds any necessary struts and then converts the 3D object into a series of 2D printable slices. And then the actual printing is fairly straightforward, and the objects were very good quality.

All in all, I was pleased with 3D printing, and have found it very useful. And now that I have the printer, I have found myself designing and printing things in other aspects of my life, including printing a replacement bobbin holder for my wife’s sewing machine, which she was ready to throw away entirely because she was unable to buy a replacement for this critical part.

I also downloaded a high quality 3D render of a dragon, which I printed and gifted to my toddler – he was very excited by it. I highly recommend anyone reading this to look into investing in a 3D printer themselves, I guarantee you will end up making useful things you had never though you would.

Finally, I’m excited to start 3D printing for neuroscience research kit, and have started a section of my website to sell the things I’ve designed..