Biofilms are typically heterogeneous in morphology, structure, and
composition, resulting in non-uniform mechanical properties. The
distribution of mechanical properties, in turn, determines the biofilm
mechanical behavior, such as deformation and detachment. Most past
studies neglected heterogeneity of biofilms. In this study, an
image-based modeling approach was developed to transform two-dimensional
optical coherence tomography biofilm images to a pixel-scale
non-Newtonian viscosity map of the biofilm. The spatial distribution of
non-Newtonian viscosity was applied in an established Oldroyd-B
constitutive model and implemented using the phase-field continuum
approach for the deformation and stress analysis. The heterogeneous
model was able to predict deformations and stresses more accurately than
a homogenous one. This is the first time, to the best of our knowledge,
that an image-based approach is used to map the mechanical heterogeneity
of biofilms for computational studies. It provides an efficient method
to characterize biofilm mechanical behavior.