Speaker
Description
Intermediate filament (IF) elongation is driven by the longitudinal annealing of semiflexible biopolymers. Although in vitro assembly is routinely characterized by microscopy and static light scattering (SLS), a unified theoretical framework linking these complementary measurements is lacking. Here, we bridge these modalities using a Smoluchowski coagulation model for semiflexible polymers. We show that a single intrinsic bimolecular rate parameter, $k_0$, governs assembly dynamics, linking microscopic filament length distributions to macroscopic dual-wavelength SLS intensity ratios. Exploiting the model's time-rescaling properties, we derive computationally efficient empirical scaling laws describing sublinear filament growth ($\sim t^{0.89}$), the transition from lognormal to gamma length distributions, and saturating SLS signal ratios. Validation with vimentin and desmin datasets reveals that thermal bending fluctuations largely offset hydrodynamic drag, producing a weakly homogeneous association kernel. The framework reduces computation from hours to seconds while enabling rapid parameter estimation and quantitative predictions across experimental modalities.
