Photothermal-manipulatable shape memory polyacrylamide/gelatin Janus hydrogel with drug carrier array for invasive wound closure and responsive drug release. International Journal of Biological Macromolecules 2025, 293, 139255.

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Traditional wound closure methods often present several issues, including additional puncture wounds, adverse effects from anesthesia, and noticeable scarring. Inspired by embryonic wound healing, a Janus hydrogel (PG/Au-Asp@PCM) is designed to manipulate non-invasive wound closure by photothermal-responsive self-contraction of PG/Au-Asp@PCM, which is attributed to the shape memory behavior of PG/Au-Asp@PCM under near-infrared (NIR). Wherein, gelatin acts as a thermally reversible “switch” and polyacrylamide creates stable and cross-linked “net-points”. The elongated PG/Au-Asp@PCM can be temporarily fixed at 4 °C, and subsequently self-contracts upon NIR irradiation, generating a recovery force of 10 kPa, adequate for the closure of wound spontaneously. The Janus hydrogel also incorporates a drug carrier loaded with phase change material (PCM) and aspirin. The PCM absorbs heat during its phase transition above 42 °C, offering the photothermal-responsive release of aspirin on-demand; additionally, it also reduces the risk of skin burn during NIR exposure. Animal studies confirm the effectiveness of PG/Au-Asp@PCM in wound closure. Moreover, wounds treated with PG/Au-Asp@PCM exhibit reduced inflammation, increased thickness of epidermal and dermal layers, and a smoother appearance without scarring. These findings reinforce the feasibility of the photothermal strategy utilizing PG/Au-Asp@PCM for non-invasive wound closure, resulting in enhanced cosmetic appearance and improved wound healing outcomes.