Viscoelastic mapping of human pancreatic tissue using wideband laser speckle rheological microscopy (WB-SHEAR)

Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease with low 5-year survival rates. Mechanical changes in the tumor microenvironment, including altered tissue stiffness and viscoelasticity, are increasingly recognized as hallmarks of disease progression. We present WideBand laser Speckle rHEologicAl mircRoscopy (WB-SHEAR), a label-free, non-contact optical technique that measures tissue viscoelasticity across a wide frequency range spanning 1–10⁵ rad/s. Applied to freshly excised pancreatic samples, WB-SHEAR revealed higher complex (G*), storage (G′), and loss (G″) moduli in tumors, with the strongest contrast between 10–1000 rad/s. Tumor tissues exhibited a reduced viscoelastic exponent (α), indicating solid-like behavior, and greater mechanical heterogeneity compared to healthy tissue. WB-SHEAR distinguished fibrotic stroma from islet regions, supporting its use as a scalable diagnostic tool. Future work will explore links to treatment response.