Background: Autologous arteriovenous fistula (AVF) is the most commonly used vascular access for end-stage renal disease patients. However, during the maturation process following AVF surgery, insufficient initial venous diameter often results in inadequate blood flow, leading to fistula maturation failure. Studies have indicated that implanting stents can enlarge the initial venous diameter and improve the success rate of AVF surgeries. However, stents made from metallic materials remain permanently in the body after implantation, posing risks such as in-stent restenosis. Methods: Our development and testing of magnesium alloy stents with a layered double hydroxide (LDH) coating to assist AVF maturation is presented in this paper. Firstly, AZ31 alloy was used as a benchmark to screen coating technologies, including anodizing, alkaline films, and LDH coatings. ZM21 tubes were then utilized to verify the transferability of optimized parameters across different substrates. Finally, the optimized coating was applied to ZM21 stents, followed by validation through in vitro degradation tests and biochemical simulations. Results: The results showed that LDH-coated AZ31 samples exhibited a 95% reduction in average corrosion rate compared to untreated samples. Additionally, the anion exchange property of the LDH layer effectively reduced the pH of the saline solution. Subsequently, LDH coatings were applied to ZM21 magnesium alloy stents, followed by in vitro degradation and biochemical simulation. Compared to untreated ZM21 stents, LDH-coated stents demonstrated a 94.9% reduction in average corrosion rate and significantly reduced the generation of soluble magnesium chloride, maintaining the solution pH below 8.0 and the Mg²⁺ concentration below 300 μg/mL. Conclusions: The results show LDH is the most effective corrosion-resistant coating and can control the degradation rate of magnesium alloy stents to enhance their support duration and biocompatibility.

Background: Otitis media with effusion (OME) is a widespread condition that causes hearing impairment, particularly in pediatric populations. Existing non-absorbable tubes often require elective or unplanned removal surgery. Bioabsorbable polylactic acid (PLA) offers a promising alternative due to its inherent biocompatibility and tunable degradation characteristics. In this study, we designed, fabricated, and comprehensively evaluated a novel PLA middle-ear ventilation tube. Methods: Bioabsorbable PLA tubes were designed and fabricated based on commercial models. In vitro biocompatibility was assessed according to ISO 10993 guidelines. A guinea pig model was used to perform in vivo evaluations, including otoscopic examinations, auditory brainstem response (ABR) measurements, micro-computed tomography (micro-CT) imaging, and histological analyses. Results: The PLA tubes were successfully designed and fabricated, exhibiting dimensions comparable to those of commercially available products. In vitro testing confirmed their biocompatibility. In vivo observations revealed that the PLA segments remained stable, with no significant inflammation detected. ABR measurements revealed no adverse impacts on hearing function. Micro-CT imaging confirmed tube integrity and indicated initial signs of degradation over a 9-month period, as evidenced by radiographic morphology. Histological analyses indicated a favorable tissue response with minimal foreign body reaction. Conclusions: The developed PLA middle-ear ventilation tube represents a highly promising alternative to conventional non-absorbable tubes. It demonstrates excellent biocompatibility, preserves auditory function, and exhibits a controlled degradation profile. This preclinical study provides strong support for further investigation and subsequent clinical trials to validate its safety and efficacy in human patients.