Monday, March 23, 2015

Chemical method (non-protein) blocking of protein microarrays

We're working to continually improve protein microarray performance.  Recently we have developed a chemical blocking procedure to increase signal to noise ratio and eliminate any potential noise caused by the most difficult body fluids, such as whole blood, cellular and tissue lysates, urine, perspiration, tears, feces, to name a few.  Data for easier samples such as serum and plasma is improved. In some immunoassay type microarrays, a patient could be making antibodies to the proteins used to block the slide surface chemistry, resulting in very high background.  An example of this is using a traditional powdered milk blocking buffer and reacting a patient blood sample who is allergic to milk proteins.   Chemical blocking buffers remove this possibility and any potential of protein blocking buffers to interact with the epitopes of proteins printed on the microarray.  The picture below is the same sample and microarray, two different results. Notice how the microarray on the right shows detectable signal whereas on the left, the signal from spots is lost in the background showing what is called "black holes" for many of the data points.