Effect of boundary conditions on the transverse thermal fluctuations of filaments and its implications for microrheological tesnsion mapping of filamentous networks

Understanding the mechanics of tissues at the scale of one to hundreds of microns is a
forefront challenge in biomechanics. At this scale, the filamentous network of the extracellular
matrix (ECM) cannot be treated as an elastic continuum; forces propagate through it along
complex paths encompassing only a small fraction of the fibers. To map tensions in such
networks under load, we propose to monitor the transverse thermal fluctuations of multiple
fibers. To that end, we discuss our calculations of the fiber fluctuations with various boundary
conditions, including complex junctions with other fibers. We also discuss fluctuations of fibers
near to their buckling transition. Finally, we address a self-consistent model of a fluctuating
fiber in a network of similar fibers. These calculations should inform a new sort of
microrheological tension mapping of the ECM via confocal fiber tracking.