Read-out of multiple optical chemical sensors by means of digital color cameras

Cooled black-and-white CCD-cameras are well-established devices to monitor the signal response of probes and sensors in imaging applications. When two (or even three) analytes are considered, the signals of interest have to be separated from each other. Generally, this is accomplished by using filter wheels or, in case of fluorescence lifetime imaging, by evaluating the different luminescent decay times of the indicators. Here we present a novel approach for signal separation of multiple sensors. It utilizes the basic setup of color CCD and CMOS cameras. The principle of color cameras is based on the application of three different types of pixels or layers, each of them sensitive towards different wavelength ranges. These detectors can be used to record and separate multiple sensor signals. With this new approach the sensor response of dual or even triple sensors can be monitored in a very straightforward manner. The only precondition is that the applied indicators emit at separable wavelengths. The applicability is demonstrated by means of a dual sensor based on luminescent probes for carbon dioxide and temperature incorporated in different polymer matrices.