in vivo Monitoring with micro-implantable hypoxia sensor based on tissue acidosis

Dulay, Samuel; Rivas, Lourdes; Miserere, Sandrine; Pla, Laura; Berdún, Sergio; Parra, Johanna; Eixarch, E.; Gratacós, E.; Illa, M.; Mir, Mònica; Samitier, J.

doi:10.1016/j.talanta.2020.122045

Cited by 10 publications

(7 citation statements)

References 41 publications

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“…The developed pH ion-selective solid-based micro-sensor exhibited a stable near Nernstian response of − 50 mV/pH unit when used in physiological range of pH 6.8-7.5. The pH calibration plot also demonstrated a wide working linear range, maintaining sensitivity in a broad pH range from 4 to 9 [ 8 ] (Fig. 2 ).…”

Section: Resultsmentioning

confidence: 99%

“…PREs was constructed by immersing the tip of the Ag wire (anode) and a corresponding Pt or Ag wire (cathode) in 3 M KCl for 2 min using 9 V battery, which resulted in the formation of Ag/AgCl layer. The PREs were then coated with Nafion® and cured at 100 °C for 1 h. Both electrodes were inserted within a piece of 5 mm PEEK tubing and stored under argon [ 8 ]..…”

Section: Methodsmentioning

confidence: 99%

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Fetal ischemia monitoring with in vivo implanted electrochemical multiparametric microsensors

et al. 2021

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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.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Fetal ischemia monitoring with in vivo implanted electrochemical multiparametric microsensors

et al. 2021

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“…The sensors used in this article were developed and optimized in previous work [13,14]. In previously reported articles, the sensitivity, specificity, reproducibility, and response time of these sensors are described, which were validated in adult rabbits.…”

Section: Miniaturized Electrochemical Sensors: Ph and Pomentioning

confidence: 99%

“…For that reason, the insulating layer of one end of the metallic wires (Pt or Ag, 15 cm in length and 125 µm in diameter) was carefully removed to solder it with a copper wire (1 m in length). Once the microsoldered section had been isolated, the modifications for preparing the working and the reference electrodes for both types of electrochemical sensor were performed as previously described [13,14]. After the sensors were individually functionalized, they were integrated into a biocompatible tube with a final diameter of 500 µm (See supporting information Figure S1).…”

Section: Miniaturized Electrochemical Sensors: Ph and Pomentioning

confidence: 99%

“…In this regard, miniaturized electrochemical sensors insertable through a needle would be required in order to monitor fetal acid-base status. Previous studies from our group have demonstrated that miniaturized electrochemical sensors could monitor oxygen or pH changes continuously in a model of ventilatory hypoxia in adult rabbits [12][13][14]. The development of a multiparametric electrochemical sensor aiming to monitor oxygen and pH at the same time would offer a great advantage in the monitoring of these pregnancies.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2021

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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.

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Implantable application of polymer‐based biosensors

Mei

Zhang

et al. 2021

Journal of Polymer Science

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Implantable sensors offer a great opportunity to extract physiological information from inside the body by real-time monitoring. With the demand for personal healthcare and point-of-care treatment, a long-term stable sensor of excellent mechanical and biological compatibility with human organs is urgently required. In contrast to rigid electronic devices using silicon or metallic materials, soft sensors are realized by flexible polymers in a simple way, endowing the implantable sensor with a tissue-mimetic structure. In this article, we systematically review the development of implantable electronic sensors based on polymer materials. The unique properties of polymers are introduced, followed by their applications in implantable device fabrication.Strategies to integrate polymers with implantable sensors, encompassing device interface, geometry, and integration, are also summarized. Furthermore, biosensing applications of polymer-based implantable devices are described, ranging from physical stimulus monitoring to biochemical analysis in vivo. Finally, we envision how advances in polymer materials may facilitate the development of intelligent sensors with broader applications in vivo.

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in vivo Monitoring with micro-implantable hypoxia sensor based on tissue acidosis

Cited by 10 publications

References 41 publications

Fetal ischemia monitoring with in vivo implanted electrochemical multiparametric microsensors

Fetal ischemia monitoring with in vivo implanted electrochemical multiparametric microsensors

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

Implantable application of polymer‐based biosensors

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