Performance validation for microplate fluorimeters.

As the sophistication of instruments that make fluorimetric measurements on samples in microplates has increased, so has the need for methods to validate instrumental performance. This paper describes a solid-state validation microplate that tests multiple aspects of fluorescence performance, including signal linearity, gain, noise, sensitivity, wavelength accuracy, and polarization stability. Both the operating principles and the validation of the validation microplate are discussed.

Fluorescence polarization and anisotropy in high throughput screening: perspectives and primer.

Fluorescence polarization and anisotropy are two nearly equivalent techniques that have together, over the past 5 years, achieved wide use in high throughput screening in drug discovery. These are single-label methods that can be used to construct homogeneous assays that are fast, sensitive, and resistant to some significant interferences. Moreover, the assays are relatively inexpensive.

Direct measurement of extracellular proton flux from isolated gastric glands.

We used the microphysiometer, a sensitive extracellular pH sensor, to resolve luminal (or apical) H+ secretion and basolateral release of OH- as well as liberation of acidic metabolites in rabbit gastric glands. Stimulation of glands via the adenosine 3',5'-cyclic monophosphate pathway produced a biphasic change in the extracellular acidification rate (EAR): after an initial transient decrease below the unstimulated baseline (-40.9 +/- 3.

Microfabrication in silicon microphysiometry.

Over the past 5 years, microphysiometry has proved an effective means for detecting physiological changes in cultured cells, particularly as a functional assay for the activation of many cellular receptors. To demonstrate the clinical relevance of this method, we have used it to detect bacterial antibiotic sensitivity and to discriminate between bacteriostatic and bacteriocidal concentrations. The light-addressable potentiometric sensor, upon which microphysiometry is based, is well suited for structural manipulations based on photolithography and micromachining, and we have begun to take advantage of this capability.