(8/x) Two modes of photochemical sectioning are possible: (a) complete degradation of the target volume (“photodegradation”) or (b) cross-sectional sectioning and lift-off of the overlaying volume (“photoslicing”). Option b preserves the sectioned volume (image: photoslicing)

(6/x) To implement VIPS, we designed and synthesized a photodegradable superabsorbent hydrogel with a custom photocleavable cross-linker (“PC”) that undergoes complete photo-decimation under UV illumination

(3/x) In more detail, conventional volumetric fluorescence imaging is constrained by a resolution/imaging depth/sample size trade-off. VIPS overcomes the microscope’s working distance limitation using iterative photochemical sectioning and on-block optical imaging

(2/x) In essence, VIPS uses a ray or sheet of light to perform spatially precise sectioning of large biological samples, such as a brain. By iteratively repeating this light-based sectioning and imaging, we can achieve volumetric optical imaging of virtually any sample size