Bionic artificial penile Tunica albuginea

The mammalian tunica albuginea (TA) is characterized by a double -layer orthogonal structure composed of stacked parallel wavy collagen fibers. During an erection, these fibers undergo sequential straightening and stretching to mediate the soft-to-firm transition. Inspired by the delicate strain-adaptive structure of natural TA, we propose an artificial TA (ATA) composed of a strain-stiffening hydro -gel consisting of aligned yet crimped fibers. This delicate structure is produced via the stretching of an isotropic polyvinyl alcohol gel fol-lowed by covalent cross-linking. ATA possesses several key mechan-ical features of natural TA, including rapid strain stiffening over small intervals of deformation, excellent fatigue resistance to sus-tain cyclic bursts, and high toughness to withstand pointwise acupuncture during suturing. Furthermore, ATA displays the capa-bility to repair injuries and restore normal erectile function of the TA-damaged penile tissue in a pig model. Our study demonstrates that ATA has great promise for penile injury repair.