Our research primarily focuses on analyzing the synaptic ultrastructure in mature retinal organoids. We aim to develop a reproducible and straightforward transmission electron microscope, or TEM, sample preparation method for retinal organoids, which could greatly benefit the field of retinal organoid research. Compared to other techniques such as optical microscope, transmission electron microscope offers the ability to characterize the ultrastructure of integral synapse and the subcellular organelles in retinal organoids at a nanoscale level.
Our protocol offers optimized conditions for transmission electron microscope sample preparation of retinal organoids, returning simple and user-friendly stats. Our findings clearly show the ultrastructure morphology of synapse within retinal organoids, including both conventional synapse and ribbon synapse. This establishes a solid foundations and presents a reproducible methods for subsequent functional investigations of retinal organoids, along with the evaluation of their clinical applications such as drug screening.