A biodegradable high-purity magnesium closing clip for general surgery

The commonly used closing clips do not fully meet clinical requirements. For instance, non-degradable titanium and plastic clips remain in the body permanently, resulting in tissue lesions due to prolonged stimulation of the surrounding tissues, and degradable polymer clips typically possess weak mechanical properties and may produce irritating degradation products. In this work, we report a promising, multifunctional, and degradable high-purity magnesium (HP-Mg) closing clip to conquer the limitations of existing clinical closing clips. The HP-Mg closing clips possess enhanced clamping capabilities, effectively avoiding hemorrhage, tissue fluid leakage, clip loosening and slipping, as well as complete degradability within approximately 360 days in vivo, mitigating the risk of permanent foreign body retention. The Mg²⁺ released from HP-Mg clips significantly promotes collagen synthesis in vascular smooth muscle, accelerating wound healing. Moreover, Mg²⁺ and H₂ released from the HP-Mg clips significantly induce the apoptosis of tumor cells. In vivo mouse, rat, and minipig models validate that the degradation products of HP-Mg clips are absorbed and metabolized by tissues, and do not cause Mg²⁺ or H₂ accumulation in major organs, pH value deviation of local tissues, severe local and systemic inflammation reactions, or artifacts in an imaging test. The self-developed biodegradable Mg closing clip received NMPA approval for marketing as a Class III medical device in 2023. The biodegradable HP-Mg closing clips offer a promising alternative to current clinical closing clips for the tubular tissues that do not require permanent closure force in laparoscopic surgery. STATEMENT OF SIGNIFICANCE: 1. We designed a biodegradable high-purity magnesium (HP-Mg) closing clip for laparoscopic surgery. It shows effective closure, complete biodegradability in vivo, no adverse reactions, and multiple biofunctions. 2. HP-Mg clips overcome limitations of current clips: non-degradable clips may cause tissue lesions, while degradable polymer clips possess weak mechanical properties and may release irritants. 3. The released Mg²⁺ promotes collagen synthesis, accelerating wound healing. The released Mg²⁺ and H₂ also induce tumor cell apoptosis. 4. HP-Mg clip was issued as an innovative medical device (Innovation No.: 201,800,018) by China's NMPA in 2018 and approved for marketing (License No.: 20,233,021,931) as a Class III medical device in 2023. It is China's first bio-Mg implant and the world's first biodegradable Mg closing clip.