Effect of Mechanical Stretching in Inducing Fiber Alignment in Collagen Gels

Abstract

Extracellular matrix reorganization has been observed in many types of tumors, including breast cancer. Specifically, collagen fiber alignment perpendicular to the tumor boundary has been associated with increased tumor invasiveness, leading to intravasation and poor prognosis in patients. In order to understand the role of mechanical forces in matrix remodeling, studies have been performed measuring the effects of using stretching devices and microfluidic channels on collagen samples. The focus of this study is strain-induced alignment of collagen fibers through mechanical stretching experiments. Several methods and fiber alignment outcomes are compared. Collagen density and amount of strain applied were found to be two parameters that influence the degree of fiber alignment when collagen gels are stretched. To some extent, strain alone was predictive of fiber alignment, with alignment not observed below 5% strain in general. However, the strain required for rupture was less consistent across studies. Overall, quantification of fiber alignment at different strains reveals that it is not possible to entirely predict alignment from strain alone. Understanding the role of other parameters in influencing fiber alignment will help clarify the impact of mechanical forces on the extracellular matrix.