BMP2 and potential inhibitor proteins can be deposited simultaneously. The image pattern for jetting the array will be the same as in Figures 1 and 3, with the image pattern for the inhibitor being the same as the BMP2 pattern, only rotated by 90°. The jetting will be coordinated with the stage motions so that these two patterns will exactly overlap using computer-vision calibration. Pattern accuracies will be verified using fluorescently-labeled BMP2 and inhibitors.