OP08.04: Mechanical properties of cyanoacrylate‐based bioadhesives and Nitinol meshes to develop a sealing system to prevent iPPROM

To evaluate the mechanical properties of different cyanoacrylate-based bioadhesives and Nitinol meshes for improving a sealing system for fetoscopy-induced membrane defects. Two-stage ex vivo experiments were conducted to evaluate different types of bioadhesives and Nitinol meshes. The first stage involved selecting the ideal bioadhesive among n-cyanoacrylate (nCA)-viscosity-inducing agent (VIA) 5%, nCA-VIA 6% and nCA-VIA 7%. The second stage involved selecting the ideal Nitinol mesh design(s) among silicone-Nitinol-6-arm-thin, silicone-Nitinol-6-arm-thick, silicone-Nitinol-8-arm-thin and silicone-Nitinol-8-arm-thick patches. Term human amniotic membranes were punctured with a 10F metal punch, and the defects were sealed with the sealing patches. The membranes were mounted on a multiaxial inflation device, and fluorescein saline solution was infused to generate hydrostatic pressure that mimics intraamniotic pressure. The maximum pressure free of leakage (MP) and bursting pressure (BP) were measured (n = 8). Intact membranes were used as controls for the two-stage experiments. There was no significant difference in MP and BP among the three bioadhesives. However, nCA-VIA 7% showed a more consistent performance in all experiments and smaller difference between MP and BP, compared with others. In the experiments for Nitinol mesh selection, silicone-Nitinol-6-arm-thin patches had a significantly higher MP than silicone-Nitinol-8-arm-thin patches (P = 0.018). Silicone-Nitinol-6-arm-thin and silicone-Nitinol-6-arm-thick patches showed higher BP, compared with other patches, with a trend towards statistical significance (P = 0.059). nCA-VIA 7% and silicone-Nitinol-6-arm-thin and silicone-Nitinol-6-arm-thick patches showed the best performance in terms of adhesion and mechanical properties. Further experiments to evaluate intermediate and long-term adhesion are needed to select the best candidates for sealing system development.