A collagen plug with shape memory to seal iatrogenic fetal membrane defects after fetoscopic surgery

Iatrogenic preterm premature rupture of fetal membranes(iPPROM)after fetal surgery remains a strong trigger for premature birth.As fetal membrane defects do not heal spontaneously and amniotic fluid leakage and chorioamniotic membrane separation may occur,we developed a biocompatible,fetoscopically-applicable collagen plug with shape memory to prevent leakage.This plug expands directly upon employment and seals fetal membranes,hence preventing amniotic fluid leakage and potentially iPPROM.Lyophilized typeⅠcollagen plugs were given shape memory and crimped to fit through a fetoscopic cannula(Ø3 mm).Expansion of the plug was examined in phosphate buffered saline(PBS).Its sealing capacity was studied ex vivo using human fetal membranes,and in situ in a porcine bladder model.The crimped plug with shape memory expanded and tripled in diameter within 1 min when placed into PBS,whereas a crimped plug without shape memory did not.In both human fetal membranes and porcine bladder,the plug expanded in the defect,secured itself and sealed the defect without membrane rupture.In conclusion,collagen plugs with shape memory are promising as medical device for rapid sealing of fetoscopic defects in fetal membranes at the endoscopic entry point.