Experiments

Temperature vs. time data for the heating element during a PCR test

The resulting data is shown in above as it displays the heating and cooling capabilities of our DIY PCR prototype. Note the different periods of temperature/time change and how they contribute to the cycles that constitute the PCR experiment. Preheating only occurs at the beginning of the PCR test, and only heating, cooling, and annealing/extension are cyclically repeated for the remainder of the test’s duration. Note that the temperatures recorded are higher than typically required for PCR experiments because the temperature recorded is for the heating element, and not all that heat is completely transferred to the sample tube, so having a higher heating element temperature ensures the sample will be adequately heated even if heat loss occurs. Based on the temperature and time results displayed on the MicroView (and confirmed using an infrared thermometer), we conclude that our prototype is able to effectively heat and cool a DNA sample for PCR testing.

Intensity vs. cycle for highlighter and water to test fluorescence sensors

To test the photodiode’s intensity readings, we conducted an experiment on yellow highlighter and plotted the fluorescence intensity vs. cycle count. We used a control group of water to compare with the highlighter mixed with water data. Some particles in highlighter fluid are fluorescent, so we expected that the intensity readings for the highlighter would be higher than for the water. The intensity vs. cycle count data for the highlighter and water tests are plotted above, with the average water intensity recorded as 0.0848 and the average highlighter intensity recorded as 0.0907.

Since the highlighter intensity was higher than the water as expected due to the fluorescent particles in the highlighter fluid, we infer that the prototype’s fluorescence sensors are working appropriately. It is worth noting that the difference between the highlighter and water data isn’t particularly drastic, but we assume this is because very little highlighter fluid could be extracted for the experiment, and most of the highlighter sample was water that diluted the small amount of fluorescent highlighter particles. Since the highlighter was diluted with water, it makes sense that it behaves similarly to the water, and the difference is due to the small amount of fluorescent highlighter fluid. Further testing using higher concentrations of highlighter and other fluorescent samples could lead to increased confidence in the intensity data, as well as running the experiments multiple times to reduce the effect of outliers.

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