Subaqueous Bioprinting: A Novel Strategy for Fetal Membrane Repair with 7‐Axis Robot‐Assisted Minimally Invasive Surgery

Abstract Premature rupture of membranes (PROM), defined as breakage of the amniotic sac prior to delivery, complicates 2–4% of pregnancies, leads to one‐third of preterm births, and increases the risk of perinatal mortality and morbidity in survivors. In situ bioprinting enables the fabrication of 3D structures directly for tissue repair or reconstruction in living animals, but is challenging to perform in the subaqueous narrow space where fetal membranes are located. This study reports a novel strategy consisting of an ultrafast photoresponsive hydrogel (1.5 s) and a 7‐axis bioprinting robot to perform subaqueous in situ bioprinting in a minimally invasive approach. Specially, a hydrogel patch with designed gel rivets is printed subaqueously for the therapeutic needs of PROM, and the patch displays robust tissue adhesion, favorable biocompatibility, mechanical properties resembling native tissues, and an appropriate sealing timescale to prolong pregnancy. Experiments performed in an in vitro uterus model and a mid‐gestational rabbit model show a favorable sealing effect for PROM, which validates the potential of this subaqueous bioprinting approach for application. This study not only expands upon in situ bioprinting techniques, but also provides valuable insights for the treatment of PROM and other diseases involving tissue injury in clinical settings.