Point spread function effect in image-based fluorescent microplate detection.

A major advantage of the image-based fluorescent microplate detection approach is the capability of using lower magnification to maximize the field of view so that color or intensity can provide a first step in isolating samples of interest in a high-throughput fashion. Lenses with low magnification typically have low numerical aperture, and consequently the effect of the point spread function and the liquid meniscus effect of small liquid volumes on standard microplates conspire to affect the intensity readings. We demonstrate this and show that the capillary well microplate design overcomes this limitation.