Illustration of the resistance of the DEAL approach towards non-specific protein absorption. A microarray was simultaneously exposed to goat α-human IgG-Alexa488/A1', goat α-human IgGAlexa647/C1' DEAL conjugates and goat α-human IgG-Alexa594 with no pendant DNA. When the arrays were not fully blocked and/or rinsed, non-specific binding was observed on the surface of the glass slide, but not on the non-complementary spots of printed DNA, i.e., spot B1 did not have fluorescence from non-complementary IgG conjugates nor did it exhibit fluorescence from proteins not encoded with DNA (goat α-human IgGAlexa594). Scale bar corresponds to 1mm.