Why are optical gels used in some cytometers?

Optical gels are utilized in cytometers primarily to minimize light loss due to refraction. When light travels through different mediums—such as air to the optical fiber or from the optical fiber into the sample—refraction can occur, leading to scattering and loss of signal. The use of optical gels, which have refractive indices that closely match those of both the optical fibers and the samples, helps to create a more seamless transition for the light. This reduces the potential for light loss and enhances the overall sensitivity and accuracy of the flow cytometry measurements. By effectively reducing refraction, these gels contribute to improved data quality in cell analysis and sorting processes.