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Team:Aberdeen Scotland/Project/Device
From 2014.igem.org
Portable Fluorescence Detector
The measurement device for automatically and efficiently analysing the test results on the go.
In order to be able to test a patient in the field, the assay needs to be analysed. As the assay results in the expression of GFP (Green Fluorescent Protein) production, it would have been next to impossible to make any meaningful measurements by hand. This is why our team has concentrated on designing a portable device that would aid the medical staff.
The operation of the device in question relies on several fundamental principles - the discrete nature of the activation and emission wavelengths for GFP, the filtering of UV light and the sensitivity range of LDRs (Light Dependent Resistors). Essentially, the device is going to measure the intensity of fluorescent light due to GFP illumination with UV light, in order to determine the amount (concentration) of GFP in the medium.
The Measurement Chamber
After the assay protocol has been finished, the cuvette is to be placed in the measurement chamber of the device. There a UV LED (Light Emitting Diode) with peak wavelength at 395 nm (the activation wavelength for GFP) shines through the cuvette and illuminates the GFP molecules in the medium. On the other side of the cuvette, after a UV filter and a Green (green pass-through) filter, the light intensity is measured by means of an LDR (Light Dependent Resistor).
Control Circuit
The LDR is connected to an Arduino, that manages and supplies power to the measuring chamber and the measuring process. In order to improve on the noisy direct-measurement values, the Arduino communicates with a RaspberryPi, that uses Wolfram Mathematica 10 (incl) software for noise reduction and data analysis. In certain cases the RaspberryPi will be able to react to incoming data by adjusting the measurement procedure employed by the Arduino through the control API.
Portability
The final milestone for the device is going to be portability. With the low-power nature of all the components in question, the device is able to operate from a small USB battery pack. The battery is charged in the mains or through a solar-panel charger. The market for such solar chargers is growing rapidly and they can be found at very affordable prices with good reliability.
