Prior to final testing of the DiaCHIP, we wanted to check if we are able to detect antibodies present in a complex solution like blood serum. Luckily, we obtained 20 year old blood serum from a rabbit that has been immunized against GFP and serum from a non-immunized rabbit. We immobilized purified GFP next to a positive and a negative control.The positive control for this experiment was biotinylated BSA whose specific binding partner is streptavidin. Additionally we wanted to make sure that no unspecific binding events are responsible for the obtained result. Therefore we spotted BSA without biotinylation as a negative control.