Biochips – fundamentals and applications - Electrochemical Sensors, Biosensors and Their Biomedical Applications - page 323

Weak
signal

High
intensity
background

FIGURE 11.17 High intensity background and weak signal (see Plate 7 for color version).

FIGURE 11.18 Spot overlap (see Plate 8 for color version).

insuffi cient rapid immersion of the nylon slides into the succinic anhydride blocking
solution. Insuffi cient blocking and precipitation of the labeled probe results in high
intensity background illumination. Hybridization that produces weak signals does not
allow any image detector to read its spot location, size, and shape. High background
intensity and weak signal spot array is shown in Fig. 11.17 (see Plate 7 for color ver-
sion). Overlapping of spots is shown in Fig. 11.18 (see Plate 8 for color version). A pos-
sible cause for spots overlap is excess rehydration during post-processing. It is therefore
necessary that sophisticated software programs are utilized to solve the problems of
non-ideal microarray spots so that gene expression can be extracted from the raw data.