User:Andy Maloney/Notebook/Lab Notebook of Andy Maloney/2010/05/24/Objective temperature control

Kinesin speed up discussions

So my data shows that kinesin speeds up over time when I do my experiments as can be seen in the below image.

Error creating thumbnail: File with dimensions greater than 12.5 MP

After speaking with both Stefan Diez at BPS 2010 and Erik Schäffer at the TKMM 2010 meeting I'm still not totally convinced that I am witnessing a temperature affect. But, I did look into temperature control.

Temperature control

So there are several ways to control the temperature of an objective. There is a company that sells a complete solution called Bioptechs for around $2k.

That seems absurd to me price wise. Eric has a paper where they describe a method of temperature control that seems to be quite nice. They use a flexible heating element that they attach to the objective and control with software and a current controller. I like this idea since we can get everything for this and it will basically be plug and play with these parts:

Parts list

• Temperature controller $284
• Heating elements $100
• Power supply $72

It seems that there is a cheap way to build a temperature controlled objective heater. Plus, if we get another temperature controller, I can build a slide warmer as well.

Light control

Another method for stabilizing the temperature for the microscope would be to get rid of the Hg lamp completely and use LEDs. Thorlabs has a solution for this in the form of a single LED element mounted on an adapter and a heat sink.

• Collimated LED $300-$400.
• Power supply $300.

Again, the power supply is ridiculously expensive and not worth it except for ease of use. One good thing about this whole setup is that I can take out the LED in the Thorlabs mount and use 3 different colored ones to get a pretty broad spectrum of colors. The LEDs can be purchase from here.

• Luxeon stars

There exists things called engineered diffusers that are capable of giving non Gaussian beams. The company is RPC photonics and you should check out some of the patterns they can make with the diffusers. Right now, I am trying to contact one of their engineers such that I can see if they have any diffusers that are capable of creating a uniform beam from the Luxeon Star configuration. If they do, then it's pretty trivial to mount the diffuser to the Thorlabs LED mount and use another lens to make the whole setup "collimated".

I should also note that Thorlabs has a liquid light guide for $400 that could be used to remove the Hg lamp from the microscope but still be able to use it via the light guide.

Temperature tests

The first test I am going to run is rather simple and was suggested by Koch already.

• Prepare a sample and take data immediately.
• After 10 minutes of data, remove the slide from the microscope.
• Let the slide sit on the bench for 30 minutes and return to the microscope for another 10 minutes of data taking.

I will try this with alpha casein and see what I get.

Andy Maloney 00:54, 25 May 2010 (EDT): Update

Error creating thumbnail: File with dimensions greater than 12.5 MP

So above are the results. This is quite interesting. Indeed there is a temperature affect from the heating of the slide due to the Hg lamp being attached to the microscope. This would suggest that we do indeed need to purchase some sort of temperature stabilization for the objective.

However, I keep seeing this really slow beginning speed when I use the alpha casein. It has happened in all of the experiments I have run using this passivation. There is something there, I just don't know what.

I would also like to point out that Erik and Stefan were correct, there is a temperature affect going on so, thanks again to those guys for the conversations!