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bioRxiv · 10.64898/2026.08.15.743111

Modulating hydrogel architecture via cross-linker length for high-resolution tissue imaging and photochemical sectioning

Yang, G.·Wang, W.·Mitra, R.·Gao, R.
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Abstract

The recent development of Volumetric Imaging via Photochemical Sectioning (VIPS) has enabled nanoscale imaging of whole-mount tissue samples of virtually any size by embedding intact tissue in a photocleavable, superabsorbent hydrogel. However, the efficacy of sample embedding, imaging, and photochemical sectioning is fundamentally governed by the mechanical stiffness, structural stability, and photodegradation kinetics of the photocleavable hydrogel (PC-gel) polymer network. To elucidate the effect of the photosensitive crosslinker design on these critical properties, we synthesized a set of photocleavable crosslinkers (PCs) with varying polyethylene glycol (PEG) backbone lengths and prepared the corresponding PC-gels under a fixed monomer formulation and polymerization condition. We quantified and compared the viscoelastic properties of the formed PC-gels at their swollen states, and found that the crosslinker length markedly reshaped the PC-gel mechanics. In addition, we evaluated the light-triggered degradation of the PC-gels using both wide-field and spatially-controlled illumination. We found that PC-1000, PC-1500, and PC-2000 gels remained comparably photodegradable, all enabling on-demand, spatially confined decrosslinking under such illuminations. These results provide practical guidelines for modulating the crosslinker architecture of PC-gel polymer networks to achieve optimal physicochemical properties for whole-mount tissue imaging using VIPS.

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Yang, G., Wang, W., Mitra, R., Gao, R.. 2026-08-19. Modulating hydrogel architecture via cross-linker length for high-resolution tissue imaging and photochemical sectioning. https://doi.org/10.64898/2026.08.15.743111

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