A Biodegradable Bioactive Glass-Based Hydration Sensor for Biomedical Applications

Monitoring changes in edema-associated intracranial pressure that complicates trauma or surgery would lead to improved outcomes. Implantable pressure sensors have been explored, but these sensors require post-surgical removal, leading to the risk of injury to brain tissue. The use of biodegradable implantable sensors would help to eliminate this risk. Here, we demonstrate a bioactive glass (BaG)-based hydration sensor. Fluorine (CaF2) containing BaG (BaG-F) was produced by adding 5, 10 or 20 wt.% of CaF2 to a BaG matrix using a melting manufacturing technique. The structure, morphology and electrical properties of the resulting constructs were evaluated to understand the physical and electrical behaviors of this BaG-based sensor. Synthesis process for the production of the BaG-F-based sensor was validated by assessing the structural and electrical properties. The structure was observed to be amorphous and dense, the porosity decreased and grain size increased with increasing CaF2 content in the BaG matrix. We demonstrated that this BaG-F chemical composition is highly sensitive to hydration, and that the electrical sensitivity (resistive-capacitive) is induced by hydration and reversed by dehydration. These properties make BaG-F suitable for use as a humidity sensor to monitor brain edema and, consequently, provide an alert for increased intracranial pressure.

Automated summary

Monitoring changes in intracranial pressure caused by edema is crucial for improving outcomes in trauma or surgery. Implantable sensors have been explored, but the risk of brain tissue injury during their removal remains. In this study, we demonstrate a bioactive glass-based hydration sensor that can effectively monitor brain edema and provide an alert for increased intracranial pressure.