Applying the sample taken three weeks after vaccination to the DiaCHIP resulted in a significant signal at the antigen spot, whereas no signal was obtained with the sample assumed to be negative. But convince yourself of how great the DiaCHIP performed. The video on the right shows these measurements right next to each other in real-time. Hier noch mehr Results beschreibung? Wie viel Blut, welche Verdünnung, welche Flussraten? Bindekurve? Ganztifizieren des Signals könnte vor allem für dieses Exp sehr interessant sein. (Stefan)
Besides tetanus, some other antigens of immunological relevance were taken into account. See all the results we obtained in terms of diagnostics, including an approach for quantification of the measurements.

We got hold of a more or less 20 years old serum of a rabbit that was immunized with GFP. This gave us the perfect opportunity to test our device with a more complex solution than antibody-dilutions.
For this experiment we used a specific Ni-NTA surface and spotted cell-free expressed GFP on the surface. For verification of correct expression of GFP with our Dia-Mix we performed a Western Blot analysis (fig. 1). With this we could prove that the cell-free expression was successful.
To obtain the specific surface an iRif slide was plasma activated and incubated with APTES and PDITC. Afterwards the Ni-NTA layer was added via incubation of the slide in Ni-NTA solution over night. The slide was blocked with blocking solution (?) and cell-free expressed GFP with a His tag ( + other GFPs?) and a positive control as well as a negative control (His-mCherry) were spotted onto the surface.
The serum of the GFP-immunized rabbit was then analysed in an iRif measurement. Binding of the GFP-antibodies present in the rabbit serum can clearly be seen, as the respective spots show a strong signal (fig. 1). A parallel measurement with serum of a rabbit that was not immunized (fig.2) does not show any binding events at the GFP spot.
With this experiment we could show that it is possible to analyse complex fluids like serum. In addition to that we demonstrated that our cell-free expressed GFP with a His-tag worked at binding partner of GFP-antibodies. Thus, His-tagged GFP was successfully expressed and immobilized on the surface, still enabling anti-GFP antibodies in a serum sample to bind.
Find out more about the preparation of the DiaCHIP by producing a protein microarray from a DNA template using cell-free expression.

Figure 2B shows the binding of anti-GFP to GFP as it was established before, measured with our own device. Look here, to see how you can build your own device for label-free detection of antibody binding on a protein microarray needing two lenses, a camera and a little bit of fine feeling (??) sensitivety/sensitiveness/finesse/sure instincts.

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