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

A groundbreaking advancement in high-resolution tissue imaging has emerged through the development of Volumetric Imaging via Photochemical Sectioning (VIPS). This technique allows for the detailed examination of entire tissue samples, regardless of their size, by encasing them in a unique photocleavable hydrogel known as a photochemical sectioning (PC)-gel.

However, the success of this method relies heavily on the properties of the PC-gel polymer network, specifically its mechanical stiffness, structural stability, and photodegradation kinetics.

To investigate the impact of crosslinker design on these crucial characteristics, researchers synthesized a series of photocleavable crosslinkers with different polyethylene glycol (PEG) backbone lengths. These crosslinkers were then incorporated into PC-gels using the same monomer formulation and polymerization conditions. The viscoelastic properties of these PC-gels were analyzed, revealing that the length of the crosslinker significantly influenced the gel's mechanics.

Further studies were conducted to assess the light-triggered degradation of the PC-gels. The findings indicated that PC-1000, PC-1500, and PC-2000 gels exhibited comparable levels of photodegradability, allowing for precise, targeted decrosslinking when exposed to specific illumination. This discovery offers practical insights into tailoring the architecture of PC-gel polymer networks, enabling researchers to optimize their properties for superior performance in VIPS.