Fluorescent layers for characterization of sectioning microscopy with coverslip-uncorrected and water immersion objectives

We describe a new method to generate thin (thickness > 200 nm) and ultrathin (thickness < 200 nm) fluorescent layers to be used for microscope optical characterization. These layers are obtained by ultramicrotomy sectioning of fluorescent acrylic slides. This technique generates sub-resolution sheets with high fluorescence emission and uniform thickness, permitting to determine the z-response of different optical sectioning systems. Compared to the state of the art, the here proposed technique allows shorter and easier manufacturing procedure. Moreover, these fluorescent layers can be employed without protective coverslips, allowing the use of the Sectioned Imaging Property (SIP)-chart characterization method with coverslip-uncorrected objectives, water immersion objectives and micro-endoscopes.