Objective heater

In microscopy, it is sometimes necessary to have a stable temperature while taking data. If you are using an oil immersion objective, then the thermal contact of the objective to the oil and the oil to your slide can cause temperature gradients in your sample. This is not a very good scenario for some experiments as is the case for the ones I do. One can stabilize the temperature of a sample by stabilizing the temperature of the objective or, by trying to stabilize the temperature of the room that your microscope is in. While the latter is not very ideal, a stabilized temperature controller that heats up an objective is doable.

As with most things in the world of science, a complete out of the box solution comes at a premium. This Instructable shows how I assembled a temperature controller for our objective with relatively cost effective parts. Another description for how I made this setup can be found in my Open Notebook Science Dissertation.

This build relies heavily on the work done by:

Mahamdeh, M., & Schäffer, E. (2009). Optical tweezers with millikelvin precision of temperature-controlled objectives and base-pair resolution. Optics Express, 17(19), 17190. doi: 10.1364/OE.17.017190.

Update 1-20-11:
As was suggested in the comments below, I'd like to add in this step how my interactions went with using TeTech during this build. As any scientist/researcher will know, companies that sell scientific equipment can be difficult to deal with at times. This was not the case when I was dealing with the customer support with TeTech. They were always informative and responsive and were willing to lend advice when ever I spoke to them or asked questions. They are by far one of my all star companies that I actually enjoy dealing with and would greatly recommend purchasing items from them to anyone.

Update 6-11-2011:
If you would like to site this build in a publication, you can use the following citation

Maloney A, Herskowitz LJ, & Koch SJ (2011) Effects of Surface Passivation on Gliding Motility Assays. PLoS ONE, 6(6): e19522. doi: 10.1371/journal.pone.0019522.

Step 1: Materials & Tools

Materials

1x Polyimide Film Heater Kit (Omega KH-KIT-EFH-15001). I personally like the kit version mainly because there is a ton of things you can make with the other heating elements and it is not that much more expensive to get the kit.
1x Copper tape. I used copper tape since it was what I had lying around. However, you can also use aluminum tape as this is what is recommended by TeTech to use with their thermistors.
1x Power supply (TeTech PS-12-8.4). I have never had a problem using MeanWell power supplies and I rather do like their ease of use.
1x Thermal spacer (Bioptechs RMS - 152019R). This part is with out a doubt the most expensive component for this build. Especially since it is nothing more than a piece of ABS plastic with RMS threads on it.
1x Temperature controller (TeTech TC-48-20).
2x 15kΩ thermistors from TeTech (MP-2444 and MP-2996).
1x Bud Industries aluminum box (AC-403) and bottom plate (BPA-1591).
2 LEDs (Yellow and Green). Any will work. I didn't use these exact ones but I wanted to include a link.
2 switches. I used one toggle switch and one rocker switch.
1x Bumpers
2x Black Banana Jack
2x Black Banana Plug
2x Yellow Banana Jack
2x Yellow Banana Plug
2x Orange Banana Jack
2x Orange Banana Plug
2x Blue Banana Jack
2x Blue Banana Plug
1x Green Banana Jack
1x Green Alligator Clip
1x Red Banana Jack
1x Red Alligator Clip

Tools

Hand punch
Deburring tool
Soldering iron
Nibbler

Comments

[hisai]

cant we get any videos of this..?

[canida]

Excellent, thanks for posting!

As an aside, I've always wanted to see Materials & Methods published with an Instructables-level of detail. Your Open Notebook links were quite inspiring. It's great to see people posting their techniques, and their failures as well as successes. Negative results are often more informative than positive, especially for cross-disciplinary study, so it's a shame most are lost. Feel free to post any of your MT motility protocols here if you so desire!

[amaloney]

Thanks for the kind remarks. I never thought about posting methods used in my lab to an Instructables but, it makes sense since people post recipes and lots of things in science are just recipes. Although posting procedures on Instructables may be for the wrong crowd. The real question is why the scientific community doesn't have an Instructables like area to post procedures to. Granted, we have journals like "Review of Scientific Instruments" but, nothing like this where anyone can comment on a post. Thanks again!

[Wazzupdoc]

Great idea. I think there is room in Instructables for all sorts of materials and methods of, by and for scientists of all ilks. It could be awfully inspiring to those wanting to take leaps beyond LED blinkies and such. It has always been a little saddening that the online scientific literature has been a "pay to play" system. You cannot even get the materials and methods section of journal articles without subscription (with some notable exceptions). Open source knowlege drives creativity at many levels. Great post and interesting project.

[amaloney]

Thanks Wazzupdoc. There are some great open access journals and some of my favorites include "PLoS ONE" and a new journal called "Open Research Computation". The idea of having scientific data and procedures freely available is a hotly debated topic. There are two things I'd like to say about posting science instructions on Instructables. The first thing is an old debate and is a moot point for open scientists but is good for background for those that don't know about it; if you post your data freely, you might get scooped. Number 2, and this is where Instructables might be able to help, exposure. Exposing your data and methods is great but, if it isn't searchable and easy to access, what good is it? It's the same thing as the adage that says if a tree falls in a forest... From my post, it is now obvious that Instructables is a site where methods and materials for science can be exposed to lots of different people. This is a good thing and opens up communication to lots of people with lots of different backgrounds. Thanks again Instructables community. You guys rock!

[Kociubinska]

You could save a bunch by using a power supply from an old PC. The use of typical power connectors would also simplify things. To ensure proper voltage from the PC power supply, the 5 V output should be loaded with a 10 ohm, 3 W resistor (the voltage regulation is controlled from this output).

[amaloney]

That is very true. Although, at the time if this build, I didn't want to mess with computer power sulplies. If I had used one, it would have saved about $100. Thanks again!

[kelseymh]

Excellent writeup, and it is refreshing to see proper scientific documentation (with references, performance plots, etc.). From your history plot, it looks like the rise time is about 3 minutes (20 s/C)? It's great that the overshoot is only 0.3 C, with that fast a ramp.

[amaloney]

It is nice and proper PID adjustment is crucial to get that type of response. It also helps that the guys at TeTech are really good at what they do with the microcontrollers and software. It made my life easier and made this system plug and play. Well, as plug and play as is possible in a laboratory environment. It's also nice that this system is about 1/4 the cost of a commercial unit.

[kelseymh]

Just out of curiosity, how come you went with TeTech rather than Omega (my lab engineer tends to use Omega for almost all of his temperature control one-offs)?

Oh, and since I didn't mention it my first comment, good luck on your thesis!

[amaloney]

The Nagy brothers at TeTech are super nice and were very responsive to all my questions/concerns. The level of customer service combined with the LabVIEW software interface made me choose TeTech as I had no desire to build my own software. Plus, they were nice enough to give me the source code for the controller and I was able to adjust it to my needs. I'll use TeTech for all my temperature control needs from now on. But that's not to discredit Omega. Omega does sell PT100's which are really nice components. Not to mention cartridge heaters which can be used to make a DIY hot plate/stirrer.

Thanks for the "good luck" with my thesis. I'll need it!

[kelseymh]

That's awesome; I always like to learn about companies that will work with their customers, rather than against them :-) You might consider adding those notes to Step 1.