Spring 11:QRT-PCR

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To-Do

• FIND & ORDER STUFF FOR HEATED LID
• get used to the new LabView code.
• test heating setup with sample vs block thermistor.
• find out data output format of labview program
• start investigating what kind of analysis I'll need to do in Python to the data

Weekly goals

• 3/25: Optics finished. Code started.
• 4/1: Heated lid finished.
• 4/8: Updated heat transfer function. Successful PCR.
• 4/15: QRT-PCR code finished.
• 4/22: Setup is ready for QRT-PCR. (i.e., the mechanical setup works)
• 4/29: Successful QRT-PCR from the side.
• 5/6: QRT-PCR from the top. Now which one was better?

Heated Lid research notes

OpenPCR first used nichrome wire and silicone tape sandwiched between two plates of aluminum...but it didn't work too well. They said it "smoked and burned out." However, they were designing for 16 samples, not just one (so we won't need to use as much wire). Also, we're not planning on using silicone tape. I still think it's worth trying.

Then they used a peltier device with an aluminum plate + thermal pad.

Another option: using a PCB. Instructions here.

Option 1: Nichrome wire Researching nichrome wire... looks like NiChrome 80 is the best. Here is the datasheet. Now for calculations:

 I = 3A
 V = 15V
 n = length of wire (feet)
 rpf = resistance per foot (ohms/ft)
 
 I = V/R = V/(n*rpf)

 rpf and n are inversely proportional - and cost goes up with rpf. So we want to minimize that.
 reasonable values seem to be:
 rpf = 6.46
 n = 0.77 feet
 which means a 30 gauge wire, d = 0.0100 inches.

Okay, this turns out to be too long. If we're looking to use only one coil of wire, using nichrome is not feasible.

Option 2: Thermal foil Mica, polyimide, silicon These are pretty expensive. Is it possible to just attach leads in random places to these foils, I wonder? That would make it cheaper. But as it is, they're more expensive than a TEC.

Progress Notes

3/22/11

Getting the temperature calculation right earned me a level-up... meaning I got to graduate to the Current Version of the Code. Got a brief intro to it. It's pretty complicated.

3/20/11

Based on model system (blue LED + ND filter), I don't think gain is high enough. Increased gain of transimpedance amp from 2.5e4 to 2.5e5. Well, it didn't help that much. So it's back the way it was. In any case, we get a significant signal (~0.25 units amplitude) with the model system. Huzzah!

After much wrestling with simple math, the temperature sensing is largely working! yay

3/18/11

Optical setup appears to be working.

3/16/11

Added dichroic mirror.

Question: how can I verify the optical setup? it seems to respond to driving signal, not fluorescence.

TODO: put away 25mm lens