Extending Standard Rotational Rheometry for Small, Irregular, Anisotropic Tissues and Gels

Abstract

Quantification of the viscoelastic properties of soft tissues and protein gels is vital to the understanding of normal tissue development and disease progression and for evaluating the cell-mediated remodeling of fibrous protein-based engineered tissues (e.g., collagen, fibrin). Rotational (shear) rheometers are theoretically well suited for characterizing the storage and loss modulus of such soft gels; however, standard “geometries” used in such devices require relatively large, homogeneous samples to generate sufficient torque for accurate analysis of very soft materials, and the analysis generally assumes linear isotropic viscoelastic behavior. Newly formed tissues and biological protein gels such as blood clots are often small, soft (low stiffness), irregularly shaped, anisotropic, and difficult to handle. The aim of this work is to develop a method that will allow the accurate characterization of small, irregular protein gels utilizing an industry-standard rheometer.