Poster V18 - Single-Probe Transcutaneous and Continuous Multi-Analyte Sensor for the Prevention of Diabetic Ketoacidosis

Introduction: To improve prevention of diabetic ketoacidosis (DKA), a novel optical multi-analyte sensor named LifeStrip is being expanded to include the continuous measurement of metabolic indicators common of DKA, enabling real time monitoring that can help guide therapy and automatically alert to a pending DKA episode. The LifeStrip is a single 300 µm wide transcutaneous flexible probe that houses a linear array of optrodes providing multiplexing capabilities (Figure). Each optrode has an analyte-specific sensing film that emits light to a photodetector worn on the skin. This LifeStrip embodiment will comprise of our existing glucose and lactate optrodes currently in clinical studies, with an additional continuous optrode for ß-hydroxybutyrate, the ketone indicative of DKA.

Materials and

Methods: The continuous ketone sensor optrode is currently under development. Preliminary prototype ketone optrodes were tested in vitro in solutions spanning the expected range of ß-hydroxybutyrate in vivo. ß-hydroxybutyrate concentrations were determined employing a working enzyme-coupled ketone optrode paired with an oxygen sensitive reference optrode to ascertain the phase shift difference representative of the calculated analyte concentration.

Results, Conclusions, and Discussions: Preliminary results show our ketone optrode responds to ß-hydroxybutyrate solutions in the range of 0-6 mM (Figure). The sensitivity of the sensor surpasses a 0.5-degree phase shift per mmol, operating above the signal to noise ratio.

Prototype ketone optrode measurements are promising for enabling a LifeStrip with DKA monitoring and warning capability. Future work includes improvements of ketone sensor stability followed by production of units for characterization, sterilization testing, and clinical studies. This addition to the LifeStrip sensing platform demonstrates the technology’s capability to expand into additional medical and health monitoring indications with the addition of new sensing chemistries.

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