Fig. 1From: Aligned nanofibrous collagen membranes from fish swim bladder as a tough and acid-resistant suture for pH-regulated stomach perforation and tendon ruptureThe morphology and structure and mechanical properties of SB. A A complete SB of grass carp with two chambers (1: stubby cylinder, 2: slender cone). B Fiber orientation of the outer layer (b1- blue line) and the inner layer (b2- blue line) are vertical. Red dotted frame (b2) showing the connecting part, which connects 2 pieces of fibrous tissue spirally to form SB. C SB HE staining for primary (c1) and decellularized (c2). D Decellularized SB cross-section by staining: Masson (d1), Sirius red (d2), Verhoeff-Van Gieson (d3) and Safranine O (d4). E SEM of inner layer (e1, e2), outer layer (e3, e4), and their cross-section (e5–7) of DUM. F SEM of inner layer (f1, f2), outer layer (f3, f4) and cross-section (f5–7) of DCM. G The Infrared spectroscopy (g1) and Raman spectroscopy (g2) of DUM and DCM. H The wet strength of IDUM and IDCM (n = 3)Back to article page