A twin-track therapeutic strategy for massive rotator cuff tears based on robust and piezoelectric nanocomposite hydrogel films

The high retear rate after massive rotator cuff tear (MRCT) repair is a significant roadblock that trouble both patients and doctors. Compared with traditional surgery, MRCT bridging repair with fascial autografts has great potential. However, the underlying risk of graft failure due to stretching and deformation during the postoperative stage is a grand challenge for its further use. In this study, we prepared robust, antimicrobial, and piezoelectric nanocomposite hydrogel films and used them for MRCT bridging repair with fascial autografts. The double-network structured nanocomposite hydrogel gel films consisting of ChNF and AA incorporate excellent mechanical properties (≈166 MPa) and remarkable antibacterial capacity. These properties ensure the gel films sustain long-term cyclic stretching and improve the anti-fatigue performance of fascial autografts. Besides, the composite gels with weakly-charged polyacrylic acid network exhibit appropriate piezoelectric behaviors, which generates electric stimulation and promotes tenogenic differentiation in vitro. Furthermore, compared to autografts alone, the combination of the nanocomposite gel films with fascial autografts shows more satisfactory results in a rabbit MRCT model, among which piezoelectric hyper-strong gels are superior to merely robust gels. This work demonstrates use of a robust, piezoelectric and antibacterial material to provide a twin-track therapeutic strategy to achieve mechanical reconstruction and biological regeneration synergistically, paving the new way to management for MRCT. • Robust, piezoelectric, and antibacterial nanocomposite hydrogel films assemble from chitin nanofibers and acrylic acid have been obtained for the first time. • The nanocomposite hydrogel films show robust mechanical property (E ≈ 166 MPa). • The nanocomposite hydrogel films improve the mechanical performance of fascial autografts. • The nanocomposite gels show appropriate piezoelectric behaviors to accelerate tissue healing. • The combination of nanocomposite gel films with fascial autografts provides a twin-track strategy for massive rotator cuff tears to synergistically achieve mechanical reconstruction and biological regeneration.