Visualizing ultrastructural details of placental tissue with super-resolution structured illumination microscopy

Super resolution fluorescence microscopy is a widely employed technique in cell biology research, yet remains relatively unexplored in the field of histopathology. Here, we describe the sample preparation steps and acquisition parameters necessary to obtain fluorescent multicolor super-resolution structured illumination microscopy images of both formalin fixed paraffin embedded and cryopreserved placental tissue sections. We compare super resolved images of chorionic villi against diffraction limited deconvolution microscopy and demonstrate the significant contrast and resolution enhancement attainable with SIM. We show that SIM resolves ultrastructural details such as the syncytiotrophoblast microvilli brush border, which up until now has been only resolvable by electron microscopy.