Rapid full-color serial sectioning tomography with speckle illumination and ultraviolet excitation.

Three-dimensional (3D) high-resolution large-volume imaging has remained a challenge. Translational rapid ultraviolet-excited sectioning tomography (TRUST) achieves rapid and cost-effective whole-organ subcellular imaging through iterative optical scanning and mechanical sectioning. However, the axial resolution is limited by the mechanical sectioning thickness or the UV light penetration depth in tissue. Here, assisted with high-and-low-frequency (HiLo) microscopy (HiLoTRUST), the optical sectioning thickness has been reduced from tens of micrometers to ~5.8 µm. In addition, HiLoTRUST has attained a finer mechanical sectioning thickness (10-15 µm) compared to TRUST (50 µm). For high-content imaging as in TRUST, we employed two additional UV light-emitting diodes (LEDs) specifically for uniform illumination. The full-color imaging ability and improved axial resolution of HiLoTRUST have been validated by two-dimensional (2D)/3D imaging of various mouse organs and human lung cancer specimens. HiLoTRUST offers a cost-effective, full-color, and high-resolution 3D imaging approach, showing its great potential in 3D histology applications.