A diameter-adaptive, suture-free conduit with magnetoelectric responsiveness promotes peripheral nerve regeneration

The repair of peripheral nerve defects necessitates the use of nerve guidance conduits (NGCs). However, the diameter mismatch between NGC and nerve, the complex suturing process, and the slow rate of axonal growth collectively leads to unsatisfactory nerve regeneration. Therefore, an ideal NGC should be diameter-adaptive, suture-free, and capable of providing electrical signals to enhance nerve regeneration. Inspired by the heat shrink tubing, we present an IR-triggered contractile and suture-free NGC with magnetoelectric responsiveness named P/A/PFeC@PAA. P/A/PFeC@PAA is composed of Pluronic F127 diacrylate mixed with Pluronic F127 (collectively referred to as P), alginate (A), and polydopamine-chelated carbon nanotube-Fe₃O₄ nanohybrid (PFeC), with an adhesive inner layer formed by polymerized acrylic acid and acrylic acid-N-hydroxysuccinimide (PAA). Under IR irradiation, the photothermal effect of PFeC induces the micellar aggregation of P and subsequent contraction of conduit, while PAA mediates adhesion to the nerve stumps, together enabling diameter-adaptive, suture-free repair. In addition, under an alternating magnetic field, anisotropic PFeC generates electrical stimulation in a noninvasive and controllable manner. This multifunctional NGC can greatly simplify the surgical procedure and provide effective post-operative support for nerve regeneration.