A near-infrared-responsive shape-memory suture for specific wound locations: noncontact self-tightening and on-demand drug delivery.
basic_science · Level V
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- Record sourced from PubMed, PMID 42061486.
- Also identified by DOI 10.1016/j.actbio.2026.04.052.
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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<sup>2+</sup>) complexes and coated with a temperature-sensitive (∼42°C) gelatin hydrogel. Upon exposure to NIR, the PDA-Cu<sup>2+</sup> 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<sub>g</sub> 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 challenging due to knot-tying complexity, instability in edematous tissue, and suboptimal clinical outcomes. Herein, we developed a near-infrared (NIR) responsive shape-memory polymer suture that integrates noncontact self-tightening and on-demand drug release. The smart suture can be pre-programmed and rapidly self-tightens upon NIR irradiation, thereby promoting wound closure. Concurrently, the photothermal effect triggered by NIR enables controlled drug release from the suture, which enhances cell-fiber interactions and facilitates incisional wound healing in targeted areas. This dual-functional design highlights its potential to provide spatially precise, on-demand therapies for specific wound regions.