Investigation of non-nucleophilic additives for the reduction of morphological anomalies in protein arrays.

Uniform spot morphology is of critical importance in the fabrication and successful use of protein arrays, and solution additives are often needed to ensure good spot quality. Whereas hydroxyl-bearing molecules such as glycerol have found wide use, in our experience these reduce the efficiency of probe immobilization (particularly in the context of aldehyde-terminated surfaces). Here, we report a series of non-nucleophilic molecules that can be used as additives to improve spot homogeneity in protein arrays. Arrayed imaging reflectometry, a label-free optical biosensing technique, has been used along with spectroscopic ellipsometry to test the spot homogeneity, antibody immobilization efficiency, and activity of antihuman IgG arrays prepared with these non-nucleophilic additives on glutaraldehyde surfaces. It has been determined that 0.1% v/v 12-crown-4 performs optimally in MPBS buffer.