Three-Dimensional Canal Architecture of Mineralised Turkey Tendon as an Architectural Analogue of Cortical Bone
Marina Borgese, Mario Raspanti, Piero Antonio Zecca, Marta Filibian, Roberta Gioia, Marina Protasoni, Marcella ReguzzoniMineralising avian tendon is a widely used experimental model for studying collagen-guided mineralisation. Yet, the three-dimensional organisation and topology of its internal canal system have never been quantitatively characterised. We combined high-resolution micro-computed tomography (micro-CT) and scanning electron microscopy (SEM) to provide the first morphometric and topological analysis of the canalicular network in mineralised turkey gastrocnemius tendon. micro-CT revealed that unmineralised canals occupy approximately 34.6% of the mineralised tissue volume and form a single continuously connected network (99.8% of void volume), with a connectivity density of ~1.3 × 102 mm−3, a fractal dimension of 2.58, a degree of anisotropy DA = 0.87 [BoneJ convention, range 0–1], and a closed-loop topology. SEM revealed marked ultrastructural heterogeneity of the mineral phase across fascicle cross-sections, consistent with graded intrafibrillar-to-interfibrillar deposition. These findings establish the first quantitative morphometric framework for physiologically mineralising collagen tissue and support the use of turkey gastrocnemius tendon as a tractable model for studying mineralisation dynamics, enthesis biology, and the design of biomimetic scaffolds with controlled porosity and anisotropy.