Broad applicability of a streamlined Ethyl Cinnamate-based clearing procedure
Turbidity and opaqueness are inherent properties of tissues which limit the capacity to acquire microscopic images through large tissues. Creating a uniform refractive index, known as tissue clearing, overcomes most of these issues. These methods have enabled researchers to image large and complex 3D structures with unprecedented depth and resolution. However, tissue clearing has been adopted to a limited extent due to a combination of cost, time, complexity of existing methods and potential negative impact on fluorescence signal. Here we describe 2Eci (2nd generation Ethyl cinnamate based clearing method) which can be used to clear a wide range of tissues, including cerebral organoids, Drosophila melanogaster, zebrafish, axolotl, and Xenopus laevis in as little as 1-5 days while preserving a broad range of fluorescence proteins including GFP, mCherry, Brainbow, and alexa-fluorophores. Ethyl cinnamate is non-toxic and can easily be used in multi-user microscope facilities. This method will open up clearing to a much broader group of researchers, due to its broad applicability, ease of use, and non-toxic nature of Ethyl cinnamate.\n\nSummary statementThe non-toxic, broadly applicable, and simplified protocol of 2Eci tissue clearing makes it possible for non-specialist labs to use clearing approaches on conventional inverted microscopes.