A novel two-component, expandable bioadhesive for exposed defect coverage: Applicability to prenatal procedures

Background/purpose: We sought to test select properties of a novel, expandable bioadhesive composite that allows for enhanced adhesion control in liquid environments. Methods: Rabbit fetuses (n = 23) underwent surgical creation of spina bifida on gestational day 22–25 (term 32–33 days). Defects were immediately covered with a two-component tough adhesive consisting of a hydrogel made of a double network of ionically crosslinked alginate and covalently crosslinked polyacrylamide linked to a bridging chitosan polymer adhesive. Animals were euthanized prior to term for different analyses, including hydraulic pressure testing. Results: Hydrogels remained adherent in 70% (16/23) of the recovered fetuses and in all of the last 14 fetuses as the procedure was optimized. Adherent hydrogels showed a median two-fold (IQR: 1.7–2.4) increase in area at euthanasia, with defect coverage confirmed by ultrasound and histology. The median maximum pressure to repair failure was 15 mmHg (IQR: 7.8–55.3), exceeding reported neonatal cerebrospinal fluid pressures. Conclusions: This novel bioadhesive composite allows for selective, stable attachment of an alginate-polyacrylamide hydrogel to specific areas of the spina bifida defect in a fetal rabbit model, while the hydrogel expands with the defect over time. It could become a valuable alternative for the prenatal repair of spina bifida and possibly other congenital anomalies. Type of study: N/A (animal and laboratory study). Level of evidence: N/A (animal and laboratory study).