Nanoscale mechanics of brain abscess: An atomic force microscopy study

Consistently with previous histological findings, we modeled the brain abscess as a multilayered structure, composed of three main layers: the cerebritis layer, the collagen capsule, and the internal inflammatory border. We probed the viscoelastic behavior of each layer separately through the measure of the apparent Young's modulus (E), that gives information about the sample stiffness, and the AFM hysteresis (H), that estimates the contribution of viscous and dissipative forces. Our experimental findings provide a full mechanical characterization of the abscess, showing an average E of (94 ± 5) kPa and H of 0.37 ± 0.01 for the cerebritis layer, an average E = (1.04 ± 0.05) MPa and H = 0.10 ± 0.01 for the collagen capsule and an average E = (9.8 ± 0.4) kPa and H = 0.57 ± 0.01 for the internal border. The results here presented have the potential to contribute to the development of novel surgical instruments dedicated to the treatment of the pathology and to stimulate the implementation of novel constitutive mechanical models for the estimation of brain compression and damage during BA progression.