UC San Diego

In this study, we demonstrate the use of Stokes polarimetry in combination with polarized light microscopy as a powerful tool in the characterization of anisotropic polymeric materials including collagen and poly (ϵ-caprolactone) fibers. Structural anisotropy has been shown to translate to optical anisotropy in the form of birefringence. We demonstrate that polarized light microscopy and Stokes polarimetry can be used to enhance the visualization of fibrous structures that are not ordinarily accessible by conventional microscopy techniques, by leveraging the birefringence of the material. With polarized light microscopy, we show the existence of birefringent Maltese cross structures in collagen synthesized at 22 0C and perform structural analysis of the system using Stokes polarimetry. The highly fibrous microstructural arrangements observed by polarized light microscopy and Stokes polarimetry for collagen synthesized at 40 0C and poly (ϵ-caprolactone) fibers can provide insights into the kinetics of polymerization. We also observe a change in birefringence due to the effect of strain on super elastic poly (ϵ-caprolactone) fibers. Overall, we demonstrate that combining Stokes polarimetry and polarized light microscopy has the potential to provide quantitative, point by point structural analysis of fibrous biomaterials. This study holds potential to provide insights into the kinetics and mechanics of disease progression and polymer synthesis.