Team:Bielefeld-CeBiTec/Design

Prototype Design

The first steps

In the beginning we wanted to test, if it could really work to photograph fluorescence with an smartphone. Therefore we got an light engineering Filter from the "Frauenkulturzentrum Bielefeld e.V." and put it in front of the camera and the flash. You can see different colors in the picture. So in our first impression we thought it's worth to try some other Filters.

The first filtertest to get an rough impression if it could work, to use two filters for fluorescence imaging. We used one Filter in front of the flash and the same one in front of the camera. In the picture you can see purified GFP, sfGFP lysat and the lysat of a not induced sfGFP culture.

Therefore we bought a lee color filter catalog and began to test different filter combinations. But before testing we decided to messure the extinction and emission spektra from sfGFP as a basis to choose the most promising filter combination and to have a look if the smartphone flash really extincts sfGFP.The preselection was possible, because every Filter had a light transmitting spektra.

Emission and extinction spektra of sfGFP. The characteristic curve from the samsung galaxy S5 mini flash is also shown. The overlap from the different spektra show, it's possible to excite sfGFP with a smartphone flash.

Lee color filter catalog

The next step was to create an dark environment. Therefore we did handicrafts to design a "black box". Now it was possible to take photos under same conditions and same background.

The black box: tinkered to take photos under same conditions

The filter combinitions

The groundwork is done. Now we had to find the ideal Filterkombination. So we made a lot of photos with the preselection in every combinition. After analyzing the photos with Fiji. The optimal filter combination was tokyo blue in front of the flash and twickenham green in front of the camera.

Test of different filtercombinations. On the top there is the picture without any filters. In the middle the picture was taken with fluorescence green in front of the camera and deep blue in front of the flash. The bottom photo was taken with the optimal filtercombinition. Tokyo blue in front of the flash and twickenham green in front of the camera

As you can see in the picture above it's really important to take the right filters. But is it only possible to photograph sfGFP and GFP? To find out, we tried to photograph monomeric red fluorescent protein (mRFP) Lysat.

Test of different filtercombinations to photograph mRFP. On the top the picture is taken without any filters. In the middle the picture was taken with light red in front of the camera and dark yellow green in front of the flash. The bottom photo was taken with the optimal filtercombinition. Twickenham green in front of the flash and light red in front of the camera.

Does it work on Paper?

So far so good. It works. But does it also works with small amongs of volume and on Paper? Therefore we toke filter paper and put the lysat on the paper and toke the photos. As you can see in the picture at the bottom, it is possible to photograph small amongs (5 µl) on Paper up to a 1:1 dilution.

We added a small among of lysat to the scrap of paper and photographed it with the different filter combinitions. The top photo is whithout any filter. The Picture in the middle was taken with the filter combinition for sfGFP and for the bottom picture the mRFP Filters were used.

Now we had to find out if we can photograph the fluorescence from the CFPS on Paper. So after a CFPS run on paper, we took the scrap of paper and took a photo from it.

We took the scrap of paper from the CFPS an took an photo. And as you can see in the picture it worked. We can take an photo of the sfGFP generated in the CFPS.

The 3D print

Ok, the fluorescence detections works fine, but it's not really practicle to take the photo. The Filter have to be the right position direct in front of the camera respectively the flash. Also it has to be quite dark for nice pictures. Therefore we designed a box and realized it with a 3D printer. The top can be changed specific for the smartphone you use. The test stripe can be placed on the push loading drawer and inserted into the box. So it's quite easy to use. You just have to put the smartphone on the top, insert the test strip an take the photo.

The 3D modell of the box

Thats nice! But how do we quantify our fluorescence output?