HOW TO USE:
The fluorescence signal is recorded using the smartphone camera and is analyzed by an in-house web-based app written by Javascript (on the right). After opening the web apps, the user can press the button “Choose file” (Fig. A) that includes two options for data analysis: “Camcorder” or “Files” as shown in the bottom of the smartphone screen (Fig. B). The “Files” option lets the saved video to be analyzed, while the “Camcorder” leads to the recording display. When the “Camcorder” is chosen, the camera focus is adjusted prior to the real-time record of the fluorescence signals during the SD step on μCE chip (Fig. C). As soon as the signal recording is finished, the data analysis is immediately conducted to show the CE electropherogram on the screen (Fig. D). Owing to the fine focus of the “Camcorder” option, the fluorescence signal of the amplicon could be monitored. When the RT-PCR amplicon approached the detection point, the fluorescence intensity gradually increased, maximized and then faded away (Fig. E). Fig. E(i)-E(iv) show the snapshots of the amplicon positioned before the detection point (Fig. E(i)), close to the detection point (Fig. E(ii)), at the detection point (Fig. E(iii)), and after the detection point (Fig. E(iv)). For the fluorescence calculation, the frame size of the video image was cropped down surrounding the detection point to minimize the effect of the background noise on the fluorescence signal. In order to obtain the cropped image, we could define the X and Y value as well as area to locate the region of interest (Top panel of Fig. D). The green pixel intensities within the defined area were averaged every second, and were plotted according to the time, producing a typical CE electropherogram (Bottom panel of Fig. D).