Non-invasive monitoring of pH and oxygen using miniaturized electrochemical sensors in an animal model of acute hypoxia

Background: One of the most prevalent causes of fetal hypoxia leading to stillbirth is placental insufficiency. Hemodynamic changes evaluated with Doppler ultrasound have been used as a surrogate marker of fetal hypoxia. However, Doppler evaluation cannot be performed continuously. As a first step, the present work aimed to evaluate the performance of miniaturized electrochemical sensors in the continuous monitoring of oxygen and pH changes in a model of acute hypoxia-acidosis. Methods: pH and oxygen electrochemical sensors were evaluated in a ventilatory hypoxia rabbit model. The ventilator hypoxia protocol included 3 differential phases: basal (100% FiO2), the hypoxia-acidosis period (10% FiO2) and recovery (100% FiO2). Sensors were tested in blood tissue (ex vivo sensing) and in muscular tissue (in vivo sensing). pH electrochemical and oxygen sensors were evaluated on the day of insertion (short-term evaluation) and pH electrochemical sensors were also tested after 5 days of insertion (long-term evaluation). pH and oxygen sensing were registered throughout the ventilatory hypoxia protocol (basal, hypoxia-acidosis, and recovery) and were compared with blood gas metabolites results from carotid artery catheterization (obtained with the EPOC blood analyzer). Finally, histological assessment was performed on the sensor insertion site. One-way ANOVA was used for the analysis of the evolution of acid-based metabolites and electrochemical sensor signaling results; a t-test was used for pre- and post-calibration analyses; and chi-square analyses for categorical variables. Results: At the short-term evaluation, both the pH and oxygen electrochemical sensors distinguished the basal and hypoxia-acidosis periods in both the in vivo and ex vivo sensing. However, only the ex vivo sensing detected the recovery period. In the long-term evaluation, the pH electrochemical sensor signal seemed to lose sensibility. Finally, histological assessment revealed no signs of alteration on the day of evaluation (short-term), whereas in the long-term evaluation a sub-acute inflammatory reaction adjacent to the implantation site was detected. Conclusions: Miniaturized electrochemical sensors represent a new generation of tools for the continuous monitoring of hypoxia-acidosis, which is especially indicated in high-risk pregnancies. Further studies including more tissue-compatible material would be required in order to improve long-term electrochemical sensing

Implication of mast cells, nerve growth factor and splanchnic nerves in postoperative ileus. Study in patients undergoing abdominal surgery and in a rat experimental model

El íleo postoperatorio (IPO) se define como el cese temporal de la motilidad propulsiva gastrointestinal (GI) en pacientes sometidos a cirugía intestinal. En pacientes y en modelos experimentales de IPO, se ha observado degranulación de mastocitos (MCs) en lavado peritoneal. Estudios con fármacos estabilizadores de MCs o en modelos en roedores carentes de mastocitos apoyan la participación de los MCs en el IPO. No obstante, los mecanismos involucrados aún están por definir. La interacción nervio-mastocito, así como la interacción con el factor de crecimiento nervioso (NGF), podrían representar un factor clave en el desarrollo del IPO. El objetivo del presente trabajo ha sido estudiar el IPO humano caracterizando la activación de los mastocitos peritoneales (PMCs) durante la cirugía colorectal. A parte, también nos propusimos explorar el papel del NGF sobre los MCs y la interacción nervio-mastocito en un modelo experimental de IPO en rata. Primero se estudió el IPO humano. Evaluamos la liberación de proteasas mastocitarias (mediante la técnica de ELISA) en el lavado peritoneal de pacientes sometidos a cirugía colorectal por laparoscopia y laparotomía, así como también la densidad de MCs (por inmunohistoquímica) y la recuperación clínica postoperatoria. Seguidamente se puso a punto un modelo de IPO en rata para profundizar en el papel de los MCs. En él, evaluamos el efecto del antagonista del receptor del NGF, K252a. Previamente habíamos demostrado el efecto in vitro del K252a sobre PMCs. Asimismo, hemos evaluado la participación de los ganglios de la raíz dorsal (DRG) en el IPO además de evaluar las consecuencias funcionales de la activación mastocitaria en animales tratados con el estabilizador de mastocitos ketotifeno o mediante la exposición del intestino al degranulador de mastocitos compuesto 48/80. Los resultados de este trabajo demuestran que la cirugía colorectal induce la liberación de proteasas mastocitarias en la cavidad peritoneal en aquellos pacientes que desarrollaron un IPO. En la rata, inmediatamente tras la inducción del modelo, se produjo un aumento en la liberación de la proteasa mastocitaria RMCP-6 (inmunoensayo) en la cavidad peritoneal. A las 24h, se observó un retraso en el tránsito GI y un aumento en la expresión de la interleuquina-6 (IL-6, RT-qPCR) y en la actividad mieloperoxidasa (MPO) en las muestras de íleon. El K252a inhibió la degranulación in vitro de los PMCs (valorada mediante el ensayo de la β-hexosaminidasa) así como también atenuó la liberación de RMCP-6 y la expresión génica tanto de IL-6, como de RMCP-2 y TrkA (receptor del NGF) en el modelo. Sin embargo, no mejoró la motilidad GI. Por otro lado, la expresión de mediadores calcitonin gene-related peptide (CGRP), NGF, TrkA and protease-activated receptor-2 en los DRGs aumentó tras la inducción del modelo. Estos cambios no se vieron afectados tras el tratamiento con ketotifeno o la exposición a C48/80. En cambio, el C48/80 si produjo un retraso en el vaciamiento gástrico/tránsito intestinal así como también aumentó la expresión de IL-6 y actividad MPO. El uso de ketotifeno, previno el retraso en el vaciamiento gástrico y la disminución post-operatoria del output fecal. Este trabajo nos permite concluir que los MCs participan en el IPO y que la interacción entre el NGF, TrkA y PMCs puede representar una diana para el tratamiento del IPO u otras alteraciones mediadas por mastocitos.Postoperative ileus (POI) is defined as a temporal cessation of propulsive gastrointestinal (GI) motility in patients undergoing abdominal surgery, especially those subjected to intestinal resection. Mast cell (MC) degranulation has been reported in patients undergoing abdominal surgery and in experimental models of POI. MC stabilizers or the use of MC-deficient mutant models point towards a role for MCs in POI, but the exact mechanisms involved remains unclear. Interactions between MCs and nerve endings or inflammatory mediators such as the nerve growth factor (NGF) may represent a key factor in POI pathogenesis. The aim of this work was to study POI in human patients by characterizing the activation of peritoneal mast cells (PMCs) in colorectal surgery. A part from that, we also aimed to explore the role of NGF antagonists on MCs and MC-nerve interactions in a rat model of POI. We firstly studied human POI. We evaluated MC protease release in peritoneal lavage (by means of ELISA) collected from patients undergoing laparoscopic and open colorectal surgery. In these patients we also studied MC density in colonic samples (by immunohistochemistry) and postoperative clinical recovery. Secondly, we set up a model of POI in rat to further explore the role of MCs. We evaluated the effect of pre-treatment with NGF receptor antagonist, K252a. In vitro effects of K252a were also evaluated on rat PMCs. Activation of dorsal root ganglia (DRG) in POI rat model was also characterized in a separate experiment in which the role of MCs was investigated using ketotifen (MC stabilizer) and compound 48/80 (C48/80, MC degranulator). Our study demonstrated release of MC proteases into peritoneal cavity after colorectal surgery. This protease release was observed only in patients with a subsequent delay of clinical recovery (those who developed POI). In our animal study we demonstrated that induction of POI by intestinal manipulation immediately evokes release of MC protease RMCP-6 in the peritoneal cavity. At 24h after intestinal manipulation, our model also presented delayed GI transit and increased expression of interleukin-6 (IL-6, RT-qPCR) and myeloperoxidase activity (MPO) in ileum samples. In contrast, density of intestinal MCs (immunohistochemistry and toluidine blue staining) and RMCP-2 and 6 gene expressions (RT-qPCR) in the ileum were unaltered in the animal POI model. K252a prevented PMC degranulation in vitro (β-hexosaminidase assay) and the release of RMCP-6 in the POI model. In addition, K252a attenuated IL-6 expression after intestinal manipulation and decreased basal peritoneal release of RMCP-2 and TrkA (NGF receptor) gene expression However, GI transit was not ameliorated after K252a treatment. Intestinal manipulation in the POI model also increased gene expression of calcitonin gene-related peptide, NGF, TrkA and protease-activated receptor-2 in somas of DRGs but these changes were not modulated by ketotifen or C48/80. In contrast, C48/80 did delay GI transit and induced up-regulation of IL-6 and MPO activity. Ketotifen also prevented delayed gastric emptying and the postoperative decrease of fecal output. To sum up, our results indicate that intestinal manipulation is associated with a local response of MCs in the peritoneal cavity. Intestinal manipulation delayed GI motility in vivo, induced intestinal inflammation and activated DRGs. K252a stabilized MCs and down-regulated IL-6 expression in the inflammatory response leading to POI. Our data also showed that MCs are involved in GI motility alteration and inflammation after intestinal manipulation. In contrast, activation of DRGs seems to be independent of MC activation based on our assessment using a pharmacological approach. We conclude that MCs participate in POI and that interactions between NGF, TrkA and PMCs may represent a target for treatment of POI or other MC-mediated diseases

Miniaturized Electrochemical Sensors to Monitor Fetal Hypoxia and Acidosis in a Pregnant Sheep Model

Perinatal asphyxia is a major cause of severe brain damage and death. For its prenatal identification, Doppler ultrasound has been used as a surrogate marker of fetal hypoxia. However, Doppler evaluation cannot be performed continuously. We have evaluated the performance of a miniaturized multiparametric sensor aiming to evaluate tissular oxygen and pH changes continuously in an umbilical cord occlusion (UCO) sheep model. The electrochemical sensors were inserted in fetal hindlimb skeletal muscle and electrochemical signals were recorded. Fetal hemodynamic changes and metabolic status were also monitored during the experiment. Additionally, histological assessment of the tissue surrounding the sensors was performed. Both electrochemical sensors detected the pO2 and pH changes induced by the UCO and these changes were correlated with hemodynamic parameters as well as with pH and oxygen content in the blood. Finally, histological assessment revealed no signs of alteration on the same day of insertion. This study provides the first evidence showing the application of miniaturized multiparametric electrochemical sensors detecting changes in oxygen and pH in skeletal muscular tissue in a fetal sheep model.This research was funded by CELLEX FOUNDATION. This work was financially supported by The Cellex Foundation and the Agència de Gestió d’Ajuts Universitaris i de Recerca (Grant 2017 SGR 1531). Additionally, E.E. has received support from the Departament de Salut (Grant SLT008/18/00156). The Nanobioengineering group at the Institute of Bioengineering of Catalonia (IBEC) has received support from the Commission for Universities and Research of the Department of Innovation, Universities, and Enterprise of the Generalitat de Catalunya (No. 2017 SGR 1079) and is part of the CERCA Programme / Generalitat de Catalunya and is supported by the Severo Ochoa programme of the Spanish Ministry of Science and Competitiveness (Grant SEV-2014-0425 (2015–2019)). CIBER-BBN is an initiative funded by the VI National R&D&i Plan 2008–2011, Iniciativa Ingenio 2010, Consolider Program, CIBER Actions and financed by the Instituto de Salud Carlos III with assistance from the European Regional Development Fund. L.R. would also like to acknowledge her support within the BEST Postdoctoral Programme, funded by the European Commission under Horizon 2020’s Marie Skłodowska-Curie Actions COFUND scheme (Grant Agreement No. 712754)

Micro-needle implantable electrochemical oxygen sensor: ex-vivo and in-vivo studies

Oxygen is vital for energy metabolism in mammals and the variability of the concentration is considered a clinical alert for a wide range of metabolic malfunctions in medicine. In this article, we describe the development and application of a micro-needle implantable platinum-based electrochemical sensor for measuring partial pressure of oxygen in intramuscular tissue (in-vivo) and vascular blood (ex-vivo). The Pt-Nafion® sensor was characterized morphological and electrochemically showing a higher sensitivity of -2.496 nA/mmHg (-1.495 nA/μM) when comparing with its bare counterpart. Our sensor was able to discriminate states with different oxygen partial pressures (pO2) for ex-vivo (blood) following the same trend of the commercial gas analyzer used as standard. For in-vivo (intramuscular) experiments, since there is not a gold standard for measuring pO2 in tissue, it was not possible to correlate the obtained currents with the pO2 in tissue. However, our sensor was able to detect clear statistical differences of O2 between hyperoxia and hypoxia states in tissue

Intraamniotic sealing of fetoscopic membrane defects in ex vivo and in vivo sheep models using an integrated semirigid bioadhesive patch

BACKGROUND: Preterm prelabor rupture of membranes is the most frequent complication of fetoscopic surgery. Strategies to seal the membrane defect created by fetoscopy have been attempted with little success. We previously developed an integrated semirigid bioadhesive patch composed of silicone and hydroxypropyl methylcellulose that achieved ex vivo sealing of membrane defects. OBJECTIVE: To evaluate the feasibility of the insertion of our integrated semirigid bioadhesive patches using a fetoscopic technique and to test the adhesion in ex vivo human membranes and in an in vivo ovine model. STUDY DESIGN: An experimental study involving 2 experiments: (1) ex vivo—human fetal membranes were mounted in a custom-designed model with saline solution simulating intraamniotic pressure. The insertion of 2 different bioadhesive patches made of silicone-hydroxypropyl methylcellulose and silicone-polyurethane-hydroxypropyl methylcellulose was performed through a 12-Fr cannula mimicking fetoscopic surgery technique. The experiment was repeated 10 times with membranes from different donors. Measures included insertion time, successful insertion, and adhesion at 5 minutes; (2) in vivo—16 patches of silicone-hydroxypropyl methylcellulose were inserted by fetoscopy in the amniotic cavity of pregnant sheep (4 bioadhesives per animal, in 4 ewes). Measures included successful insertion, adhesion at 5 minutes, and adhesion at the end of surgery. RESULTS: In the ex vivo insertion study, there was no difference in the insertion time between silicone-hydroxypropyl methylcellulose and silicone-polyurethane-hydroxypropyl methylcellulose patches (P=.49). Insertion was successful in all cases, but complete adhesion at 5 minutes was superior for silicone-hydroxypropyl methylcellulose (P=.02). In the in vivo study, insertion of silicone-hydroxypropyl methylcellulose by fetoscopy was feasible and successful in all cases, and no complications were reported. Adhesion persisted at 5 minutes and at the end of the surgery in 68.8% and 56.3% of the patches, respectively. CONCLUSION: We describe the feasibility of deploying through a fetoscopic trocar a semirigid silicone-hydroxypropyl methylcellulose patch that seals fetal membranes after an invasive fetal procedure. The results warrant further research for improving long-term adhesion and developing a clinically applicable system.This project has been funded by the Cellex Foundation and the Erasmus+ Programme of the European Union (Framework Agreement number: 2013-0040). This publication reflects only the authors’ views, and the Commission cannot be held responsible for any use that may be made of the information contained therein. T.M. was supported by a predoctoral grant from Erasmus Mundus FetalMed-PhD. E.E. has received funding from the Departament de Salut under grant number SLT008/18/00156.Peer ReviewedPostprint (published version

Expression of Interest: The Canfranc Axion Detection Experiment (CADEx)

Trabajo presentado al 29th Meeting of the LSC Scientific Committee, celebrado online del 30 de noviembre al 1 de diciembre de 2021.Peer reviewe

Implication of mast cells, nerve growth factor and splanchnic nerves in postoperative ileus. Study in patients undergoing abdominal surgery and in a rat experimental model

El íleo postoperatorio (IPO) se define como el cese temporal de la motilidad propulsiva gastrointestinal (GI) en pacientes sometidos a cirugía intestinal. En pacientes y en modelos experimentales de IPO, se ha observado degranulación de mastocitos (MCs) en lavado peritoneal. Estudios con fármacos estabilizadores de MCs o en modelos en roedores carentes de mastocitos apoyan la participación de los MCs en el IPO. No obstante, los mecanismos involucrados aún están por definir. La interacción nervio-mastocito, así como la interacción con el factor de crecimiento nervioso (NGF), podrían representar un factor clave en el desarrollo del IPO. El objetivo del presente trabajo ha sido estudiar el IPO humano caracterizando la activación de los mastocitos peritoneales (PMCs) durante la cirugía colorectal. A parte, también nos propusimos explorar el papel del NGF sobre los MCs y la interacción nervio-mastocito en un modelo experimental de IPO en rata. Primero se estudió el IPO humano. Evaluamos la liberación de proteasas mastocitarias (mediante la técnica de ELISA) en el lavado peritoneal de pacientes sometidos a cirugía colorectal por laparoscopia y laparotomía, así como también la densidad de MCs (por inmunohistoquímica) y la recuperación clínica postoperatoria. Seguidamente se puso a punto un modelo de IPO en rata para profundizar en el papel de los MCs. En él, evaluamos el efecto del antagonista del receptor del NGF, K252a. Previamente habíamos demostrado el efecto in vitro del K252a sobre PMCs. Asimismo, hemos evaluado la participación de los ganglios de la raíz dorsal (DRG) en el IPO además de evaluar las consecuencias funcionales de la activación mastocitaria en animales tratados con el estabilizador de mastocitos ketotifeno o mediante la exposición del intestino al degranulador de mastocitos compuesto 48/80. Los resultados de este trabajo demuestran que la cirugía colorectal induce la liberación de proteasas mastocitarias en la cavidad peritoneal en aquellos pacientes que desarrollaron un IPO. En la rata, inmediatamente tras la inducción del modelo, se produjo un aumento en la liberación de la proteasa mastocitaria RMCP-6 (inmunoensayo) en la cavidad peritoneal. A las 24h, se observó un retraso en el tránsito GI y un aumento en la expresión de la interleuquina-6 (IL-6, RT-qPCR) y en la actividad mieloperoxidasa (MPO) en las muestras de íleon. El K252a inhibió la degranulación in vitro de los PMCs (valorada mediante el ensayo de la β-hexosaminidasa) así como también atenuó la liberación de RMCP-6 y la expresión génica tanto de IL-6, como de RMCP-2 y TrkA (receptor del NGF) en el modelo. Sin embargo, no mejoró la motilidad GI. Por otro lado, la expresión de mediadores calcitonin gene-related peptide (CGRP), NGF, TrkA and protease-activated receptor-2 en los DRGs aumentó tras la inducción del modelo. Estos cambios no se vieron afectados tras el tratamiento con ketotifeno o la exposición a C48/80. En cambio, el C48/80 si produjo un retraso en el vaciamiento gástrico/tránsito intestinal así como también aumentó la expresión de IL-6 y actividad MPO. El uso de ketotifeno, previno el retraso en el vaciamiento gástrico y la disminución post-operatoria del output fecal. Este trabajo nos permite concluir que los MCs participan en el IPO y que la interacción entre el NGF, TrkA y PMCs puede representar una diana para el tratamiento del IPO u otras alteraciones mediadas por mastocitos.Postoperative ileus (POI) is defined as a temporal cessation of propulsive gastrointestinal (GI) motility in patients undergoing abdominal surgery, especially those subjected to intestinal resection. Mast cell (MC) degranulation has been reported in patients undergoing abdominal surgery and in experimental models of POI. MC stabilizers or the use of MC-deficient mutant models point towards a role for MCs in POI, but the exact mechanisms involved remains unclear. Interactions between MCs and nerve endings or inflammatory mediators such as the nerve growth factor (NGF) may represent a key factor in POI pathogenesis. The aim of this work was to study POI in human patients by characterizing the activation of peritoneal mast cells (PMCs) in colorectal surgery. A part from that, we also aimed to explore the role of NGF antagonists on MCs and MC-nerve interactions in a rat model of POI. We firstly studied human POI. We evaluated MC protease release in peritoneal lavage (by means of ELISA) collected from patients undergoing laparoscopic and open colorectal surgery. In these patients we also studied MC density in colonic samples (by immunohistochemistry) and postoperative clinical recovery. Secondly, we set up a model of POI in rat to further explore the role of MCs. We evaluated the effect of pre-treatment with NGF receptor antagonist, K252a. In vitro effects of K252a were also evaluated on rat PMCs. Activation of dorsal root ganglia (DRG) in POI rat model was also characterized in a separate experiment in which the role of MCs was investigated using ketotifen (MC stabilizer) and compound 48/80 (C48/80, MC degranulator). Our study demonstrated release of MC proteases into peritoneal cavity after colorectal surgery. This protease release was observed only in patients with a subsequent delay of clinical recovery (those who developed POI). In our animal study we demonstrated that induction of POI by intestinal manipulation immediately evokes release of MC protease RMCP-6 in the peritoneal cavity. At 24h after intestinal manipulation, our model also presented delayed GI transit and increased expression of interleukin-6 (IL-6, RT-qPCR) and myeloperoxidase activity (MPO) in ileum samples. In contrast, density of intestinal MCs (immunohistochemistry and toluidine blue staining) and RMCP-2 and 6 gene expressions (RT-qPCR) in the ileum were unaltered in the animal POI model. K252a prevented PMC degranulation in vitro (β-hexosaminidase assay) and the release of RMCP-6 in the POI model. In addition, K252a attenuated IL-6 expression after intestinal manipulation and decreased basal peritoneal release of RMCP-2 and TrkA (NGF receptor) gene expression However, GI transit was not ameliorated after K252a treatment. Intestinal manipulation in the POI model also increased gene expression of calcitonin gene-related peptide, NGF, TrkA and protease-activated receptor-2 in somas of DRGs but these changes were not modulated by ketotifen or C48/80. In contrast, C48/80 did delay GI transit and induced up-regulation of IL-6 and MPO activity. Ketotifen also prevented delayed gastric emptying and the postoperative decrease of fecal output. To sum up, our results indicate that intestinal manipulation is associated with a local response of MCs in the peritoneal cavity. Intestinal manipulation delayed GI motility in vivo, induced intestinal inflammation and activated DRGs. K252a stabilized MCs and down-regulated IL-6 expression in the inflammatory response leading to POI. Our data also showed that MCs are involved in GI motility alteration and inflammation after intestinal manipulation. In contrast, activation of DRGs seems to be independent of MC activation based on our assessment using a pharmacological approach. We conclude that MCs participate in POI and that interactions between NGF, TrkA and PMCs may represent a target for treatment of POI or other MC-mediated diseases

Fetal ischemia monitoring with in vivo implanted electrochemical multiparametric microsensors

Under intrauterine growth restriction (IUGR), abnormal attainment of the nutrients and oxygen by the fetus restricts the normal evolution of the prenatal causing in many cases high morbidity being one of the top-ten causes of neonatal death. The current gold standards in hospitals to detect this relevant problem is the clinical observation by echography, cardiotocography and Doppler. These qualitative techniques are not conclusive and requires risky invasive fetal scalp blood testing and/or amniocentesis. We developed micro-implantable multiparametric electrochemical sensors for measuring ischemia in real time in fetal tissue and vascular. This implantable technology is designed to continuous monitoring for an early detection of ischemia to avoid potential fetal injury. Two miniaturized electrochemical sensors were developed based on oxygen and pH detection. The sensors were optimized in vitro under controlled concentration, to assess the selectivity and sensitivity required. The sensors were then validated in vivo in the ewe fetus model, by means of their insertion in the muscle leg and inside the iliac artery of the fetus. Ischemia was achieved by gradually obstructing the umbilical cord to regulate the amount of blood reaching the fetus. An important challenge in fetal monitoring is the detection of low levels of oxygen and pH changes under ischemic conditions, requiring high sensitivity sensors. Significant differences were observed in both; pH and pO2 sensors under changes from normoxia to hypoxia states in the fetus tissue and vascular with both sensors. Herein, we demonstrate the feasibility of the developed sensors for future fetal monitoring in medical applications

Intraamniotic sealing of fetoscopic membrane defects in ex vivo and in vivo sheep models using an integrated semi-rigid bioadhesive patch

Background Preterm prelabor rupture of membranes is the most frequent complication of fetoscopic surgery. Strategies to seal the membrane defect created by fetoscopy have been attempted with little success. We previously developed an integrated semi-rigid bioadhesive patch to seal fetal membrane defects composed of silicone and hydroxypropyl methylcellulose (HPMC) that achieved ex vivo sealing of membrane defects. Objective To evaluate the feasibility of the insertion of our integrated semi-rigid bioadhesive patches using a fetoscopic technique and to test the adhesion in ex vivo human membranes and in vivo ovine model. Study design An experimental study involving two experiments 1) Ex vivo: human fetal membranes were mounted in a custom-designed model with saline solution simulating intraamniotic pressure. The insertion of two different bioadhesive patches made of silicone-HPMC (S-HPMC) and silicone-polyurethane-HPMC (SPU-HPMC) was performed through a 12-Fr cannula mimicking fetoscopic surgery technique. The experiment was repeated 10 times with membranes from different donors. Measures insertion time, successful insertion and adhesion at five minutes. 2) In vivo: 16 patches S-HPMC were inserted by fetoscopy in the amniotic cavity of pregnant sheep (4 bioadhesives per animal, in 4 ewes). Measures successful insertion, adhesion at 5 minutes and adhesion at the end of surgery. Results 1) Ex vivoinsertion study: there was no difference in the insertion time between S-HPMC and SPU-HPMC (p=0.49). Insertion was successful in all cases, but complete adhesion at 5 minutes was superior for S-HPMC (p=0.02). 2) In vivostudy: Insertion of S-HPMC by fetoscopy was feasible and successful in the totality of cases and no complications were reported. Adhesion persisted at 5 minutes and at the end of the surgery in 68.8 and 56.3% of the patches, respectively. Conclusion We describe the feasibility of deploying through a fetoscopic trocar a semi-rigid S-HPMC patch that seals fetal membranes after a fetal invasive procedure. The results warrant further research for improving long-term adhesion and develop a clinically applicable system