Macrorheology and particle tracking to study tracer transport, viscoelasticity and network structure of mucin and mucin-like biopolymer solutions

Passive microrheology using single-particle and multi-particle techniques can be used to assess the local transport, mechanical properties and network structure of biopolymer laden biological fluids. Using single particle tracking (SPT) and multiple particle tracking (MPT) passive microrheology, we probe the dynamics of tracer particles ranging from 0.1 to 10 microns in size in mucin-like Carboxy Methylcellulose (CMC) solutions and in re-constituited mucin solutions. Tracking and linking algorithms implemented in MATLAB and Python reconstruct 2-dimensional trajectories from sequential list of particle coordinates. Corrected data is used to calculate the distributions of displacements and velocities, ensemble averaged mean square displacement, and particle velocity autocorrelations from which we extract diffusion coefficients of the particles and tracer-size dependent viscoelastic properties of the medium. Passive microrheology combined with macrorheology studies and confocal derived connectivity and morphology measurements provide a base state to understand the dynamics of living active materials such Candida albicans biofilms.