Changes

The chemical reaction occurs in a microfluidic cartridge. To convert the analogue light signal into a digital signal, the emitted light from a cartridge is led through an optical setup in a cage system. First, the light from the cartridge, which is considered as a point source, is collimated by a plano-convex lens (f=25.4 mm). The emission spectrum of the bioluminescent protein has two maxima as it consists of the signal from both mNeonGreen-Nanoluc and NanoBiT. For this reason, the spectrum is split at the minimum between these maxima into a green and a blue beam. This is done through means of a long-pass dichroic mirror at 490 nm at an angle of 45 degrees. Afterwards, the green and blue beams are focused (plano-convex, f=25.4 mm) on the photodiodes (Thorlabs PDF10A, Si fW Sensitivity Fixed Gain Detector 320-1100 nm). An overview of the optical setup is given in figure 2 on the next page. The photodiodes provide an analog signal that is converted with an ADC and processed in a Raspberry-Pi comput.

For the sample handling a disposable cartridge with one chamber, an inlet and an outlet is used.

The used photodiodes provide an analog output signal between 0-10V. A voltage divider is used to transform the actual voltage range to the range of 0-5V. This signal is converted by the ADC (ADS1115 16-bit) to a digital signal, so it can be processed by the Raspberry Pi (3B+). The photodiodes and Raspberry Pi are powered by one power supply (Farnell RPT-60B). A 7-inch LCD touchscreen makes it possible to interact with the device.

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