Passive microrheology in carrageenan-fibrin mixtures using video microscopy

Abstract

Passive microrheology was demonstrated to assess the viscoelastic properties of carrageenan-fibrin mixtures. Carrageenan-based hydrogels have become promising candidates as biomimetic materials due to their biocompatible and non-cytotoxic properties. The colloidal probe particles were freely-diffusing in the aforementioned mixture, with their movement traced by video microscopy. Their motion was quantified using mean square displacement (MSD), obtained from the generalizations of the Stokes-Einstein relations. The analysis of tracer particle movement revealed that at high fibrin concentrations, the particles were eventually confined and exhibited sub-diffusion behavior based on their MSD in contrast to pure samples. Moreover, the G' and G'' of the carrageenan-fibrin mixtures calculated from the unilateral Laplace transform of the MSD revealed the changes in the material's viscoelastic behavior at varying concentrations. Although, systematic errors may arise from the microscope-camera setup calibration including random noise and drifting of tracer particles. This study shows a new and alternative way to probe into the microrheological properties of carrageenan-fibrin mixtures using video microscopy involving the implementation of particle tracking. Thereby elucidating the correlation of the tracer particle's MSD and the biopolymer's viscoelastic properties.