近红外响应型形状记忆缝线用于非接触自收紧和按需药物递送促进伤口愈合

Abstract

Chronic disease-associated wounds pose significant challenges in suturing, encompassing knot-tying complexity in minimally invasive procedures, instability in edematous wounds, and unsatisfactory wound healing. Herein, we introduce a concept of near-infrared (NIR)-responsive shape-memory polymer (SMP) suture featuring dual functionality: NIR-triggered shape-memory recovery and on-demand drug delivery. The SMP suture is synthesized from poly(L-lactide) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate). Subsequently, it is modified with copper ion-chelated polydopamine (PDA-Cu 2+ ) complexes and coated with a temperature-sensitive (∼42°C) gelatin hydrogel. Upon exposure to NIR, the PDA-Cu 2+ complexes induce a rapid photothermal effect, which triggers noncontact self-tightening (∼25 s recovery time and near-complete shape recover) of the programmed suture with 80% pre-strain to accelerate wound closure. Meanwhile, the NIR-increased heat governs the "gel-sol" transition of the hydrogel that lowers suture’s T g to 51.46, enhances recovery force to ∼0.4 N and reduces suture friction force to ∼0.35 N, and initiates a "off-on" drug release. Such a NIR-responsive mechanism not only significantly improves fibroblast growth and functionality by enhancing cell-fiber interactions in vitro , but also mitigates inflammatory response and stimulates neovascularization to advance skin regeneration in vivo . Overall, this study develops an NIR-responsive SMP suture with noncontact self-tightening and controlled drug release, enabling on-demand therapeutic interventions for specific wound locations. Statement of Significance For chronic disease-related wounds, high-performance sutures with advanced biofunctionalities have been extensively explored to accelerate healing, as surgical sutures help wound closure while minimizing scar formation. Nevertheless, suturing such wounds remains