| Abstract Scope |
There is a need in trauma medicine for simple-to-use, low-cost diagnostic devices that can continuously monitor trends in concentrations of biomarkers, such as potassium, calcium, and sodium ions, or pH. I will discuss our team’s efforts towards ion-selective sensors on flexible patches, using minimally invasive microneedle-based sensor arrays designed to sample the interstitial fluid underneath the skin. Using different nanostructured carbon materials as solid contacts and polymeric ion-selective membranes coated on acupuncture microneedles, we obtained fast sensor responses with Nernstian behavior across relevant concentration ranges. The high surface area carbon materials provided a large double-layer capacitance during the sensing process so that drifts in measured potential were minimized, reducing the need for multiple calibration steps. These microneedle sensors have the same selectivity and sensitivity as bulky, standard laboratory potentiometric sensors in response to electrolyte solutions. Their mechanical robustness was tested by inserting the microneedle electrodes into silicone skin phantoms. |