Improved calibration of electrochemical aptamer-based sensors

Electrochemical aptamer-based (EAB) sensors support the real-time, high frequency measurement of pharmaceuticals and metabolites in-situ in the living body, rendering them a potentially powerful technology for both research and clinical applications. Here we explore quantification using EAB sensors, examining the impact of media selection and temperature on measurement performance. Using freshly-collected, undiluted whole blood at body temperature as both our calibration and measurement conditions, we demonstrate accuracy of better than +/- 10% for the measurement of our test bed drug, vancomycin. Comparing titrations collected at room and body temperature, we find that matching the temperature of calibration curve collection to the temperature used during measurements improves quantification by reducing differences in sensor gain and binding curve midpoint. We likewise find that, because blood age impacts the sensor response, calibrating in freshly collected blood can improve quantification. Finally, we demonstrate the use of non-blood proxy media to achieve calibration without the need to collect fresh whole blood.

Automated summary

Electrochemical aptamer-based (EAB) sensors show great potential for real-time and high frequency measurement of pharmaceuticals and metabolites in the living body. This study investigates the quantification using EAB sensors and examines the impact of media selection and temperature on measurement performance. The results demonstrate the accuracy of better than +/- 10% for the measurement of vancomycin using freshly-collected, undiluted whole blood at body temperature. Matching the temperature of calibration curve collection to the measurement temperature improves quantification and calibrating in freshly collected blood can also enhance the accuracy. The use of non-blood proxy media for calibration is also explored.