Fig 5. Measurement of GBM E using magnetic bead displacement.

Glomeruli were isolated by perfusion with 4.5 μm magnetic beads, and decellularized with detergents and DNase. The GBMs were stored in PBS at 4°C where they formed aggregates. Fragments of the aggregates on the order of 30 x 150 x 200 μm were attached to APTES-coated glass coverslips and imaged using a confocal video microscope (Leica) where the beads seen as dark spots (arrows) were localized in X, Y, and Z dimensions (Panel 5A, XY plane). Panel 5B shows a bead in the XZ plane before activation of the magnet. Panel 5C shows the same bead in the XZ plane 5 min after activation of the magnet. The movement of the bead is evident from its relationship to the bottom of the image. The magnetic force and bead displacement were calculated in the Z axis for four beads, and the Young’s modulus, E, was calculated with the method of Kamgoue et al [18].