Plate Reader Application Guide
Basics of Plate Readers
Fluorescence plate readers are non-imaging instruments used to measure bulk fluorescence signals from samples, typically contained in multi-well plates. These systems are commonly used in assays involving large numbers of samples, such as biochemical measurements, drug screening, and protein quantification.
Unlike microscopy-based techniques, plate readers measure overall fluorescence intensity rather than spatial information. As a result, signal accuracy and consistency are the primary considerations.
Total internal reflection fluorescence (TIRF) microscopy places unusually high demands on emission filters and dichroic mirrors. Unlike standard widefield setups, the reflected excitation beam travels back through the objective — meaning emission filters must block excitation energy they'd never see in other configurations, and dichroic mirrors must maintain flatness specifications that are difficult to achieve with standard manufacturing methods.
Filter Requirements for Plate Readers
Plate readers typically use excitation and emission filters to define the spectral range of illumination and detection. Narrow bandpass filters are often preferred, as they improve signal specificity and reduce background by limiting spectral overlap.
Because these systems measure total signal intensity rather than images, careful control of excitation and emission bandwidth helps prevent detector saturation and improves measurement reproducibility.
In addition to fluorescence measurements, plate readers are often used for absorbance-based assays. In these cases, excitation filters (with or without emission filters) are used to define the wavelength range, and signal is determined by comparing transmitted light intensity between reference and sample wells.
Additional Resources
Still Have Questions?
Our applications team works with plate reader setups across most major commercial platforms. Tell us your instrument and fluorochromes and we'll point you in the right direction.
