iGEM Bielefeld 2015

Output signal

An easy way of fluorescence detection

We wanted to design a practical test strip for everyone. While superfolder GFP is the ideal reporter protein for in vitro protein synthesis, it is not visible to the human eye under normal conditions (Lentini et al, 2013). We investigated previous iGEM projects with comparable needs and aims, e.g. iGEM Aachen 2014. They used a filter in front of a sensor to detect fluorescence. Sadly, results were not satisfactory. Another approach is to put a filter in front of the flashlight (Hossain et al, 2014). In this study a photo that had been taken with a smartphone camera was analyzed.

Both approaches use only one filter, whereas both emission and extinction require different filters. In our new approach to filters are used on a smartphone in front of camera and flashlight, one filter for emission and one for extinction. With this technique we can detect the fluorescence specifically and display it on an image. Nevertheless, it is still not easily practicable for the end user. Hence, we decided to develop a smartphone app for the analysis of the fluorescence as the output signal. You only have to take a photo with two filters attached to your smartphone and the app analyzes it and displays the information about the substances that were detected. We have successfully applied this to our free biosensor detecting system with several combined heavy metals and date rape drugs.

Furthermore, it is important to take the photo in a dark environment. Therefore, we designed a black case in which the test strip can be placed. This black case enables a suitable positioning of smartphone, filters and test strip. The black case can be 3D printed and is therefor cheap and easily customizable.

In short: We provide an easy method for fluorescence detection and analysis.


Lentini, Roberta; Forlin, Michele; Martini, Laura; Del Bianco, Cristina; Spencer, Amy C.; Torino, Domenica; Mansy, Sheref S. (2013): Fluorescent proteins and in vitro genetic organization for cell-free synthetic biology. In ACS synthetic biology 2 (9), pp. 482–489. DOI: 10.1021/sb400003y

Hossain, Arafat; Canning, John; Ast, Sandra; Rutledge, Peter J.; Yen, Teh Li; Jamalipour, Abbas. (2014): Lab-in-a-phone: Smartphone-based Portable Fluorometer for pH Field Measurements of Environmental Water. In Sensors Journal, IEEE, pp. 5095-5102. DOI: 10.1109/JSEN.2014.2361651