A Versatile Three Dimensional Traction Force Microscopy Framework for Uncovering the Mechanics of Bio-Adhesion

This study presents a novel, versatile traction force microscopy framework for quantifying three-dimensional (3D) interfacial forces during bio-adhesion by integrating in situ stereo-digital image correlation with finite element (FE) simulation. The method enables accurate measurement of microscale displacements and force distributions at the interfaces in both dry and wet environments, addressing limitations of conventional microscopy techniques related to limited measurement scales, restricted fields of view, and surface disturbance from contact or fluorescence. An analytical model was developed to guide the design of a deformable substrate, supporting selection of subtrate material and thickness of the substrate. System accuracy was examined through steel ball compression experiments, which were validated against FE simulations. The framework was applied to marine mussel plaque adhesion under 15° directional tension to characterize interfacial traction force distributions. Sensitivity analyses examined the effects of Poisson's ratio, Young's modulus, and constitutive models on the results. This approach offers a versatile platform for investigating interfacial mechanics in adhesives, with broad relevance to bioengineering applications.