Biophysical Society Thematic Meeting | Riga 2026

Active and Responsive Soft Matter: From Biological to Engineered Systems

Poster Abstracts

4-POS Board 4 BIOMECHANICS OF IRIS-INSPIRED BIOHYBRID ACTUATOR Roi Habba 1 ; Ori Taitel 2 ; Oren Tchaicheeyan 1 ; Ayelet Lesman 1 ; 1 Tel aviv University, Mechanical Engineering, Tel Aviv, Israel 2 Tel aviv University, Faculty of Life Sciences, School of Biochemistry Neurobiology Biophysics, Tel Aviv, Israel The human iris is a canonical example of antagonistic biological mechanics, where radially and circumferentially aligned muscle layers cooperate to regulate pupil diameter. Despite its importance, the relationship between tissue geometry, anisotropy, and emergent mechanical function in such systems remains poorly understood.Here, we present an iris-inspired biohybrid platform designed not only to mimic this architecture, but to serve as a controllable model for studying its underlying biophysical principles. Using 3D micropatterning within hydrogels, we program muscle myoblasts into spatially defined radial and circumferential domains, enabling the formation of stable, multi-oriented constructs over a 20-day differentiation period. Structural organization and maturation are quantified via confocal imaging and fusion index analysis. Combining experiments with finite element modeling, we investigate how geometric parameters and matrix stiffness govern collective contraction and emergent opening–closing behavior. This framework allows us to probe how local cellular alignment translates into global mechanical response, and to explore the coupling between tissue architecture and function in antagonistic systems. By recapitulating key features of iris organization in a tunable in vitro platform, this work establishes a model system for studying the biophysics of geometry–mechanics relationships in active tissues, with potential to address fundamental questions on how structure encodes mechanical function in complex biological actuators.

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