Subsecond-Resolved Molecular Measurements in the Living Body Using Chronoamperometrically Interrogated Aptamer-Based Sensors

Netzahualcóyotl Arroyo-Currás, Philippe Dauphin-Ducharme, Gabriel Ortega, Kyle L. Ploense, Tod E. Kippin, Kevin W. Plaxco

Research output: Contribution to journalArticlepeer-review


Electrochemical, aptamer-based (E-AB) sensors support the continuous, real-time measurement of specific small molecules directly in situ in the living body over the course of many hours. They achieve this by employing binding-induced conformational changes to alter electron transfer from a redox-reporter-modified, electrode-attached aptamer. Previously we have used voltammetry (cyclic, alternating current, and square wave) to monitor this binding-induced change in transfer kinetics indirectly. Here, however, we demonstrate the potential advantages of employing chronoamperometry to measure the change in kinetics directly. In this approach target concentration is reported via changes in the lifetime of the exponential current decay seen when the sensor is subjected to a potential step. Because the lifetime of this decay is independent of its amplitude (e.g., insensitive to variations in the number of aptamer probes on the electrode), chronoamperometrically interrogated E-AB sensors are calibration-free and resistant to drift. Chronoamperometric measurements can also be performed in a few hundred milliseconds, improving the previous few-second time resolution of E-AB sensing by an order of magnitude. To illustrate the potential value of the approach we demonstrate here the calibration-free measurement of the drug tobramycin in situ in the living body with 300 ms time resolution and unprecedented, few-percent precision in the determination of its pharmacokinetic phases.

Original languageEnglish (US)
Pages (from-to)360-366
Number of pages7
JournalACS sensors
Issue number2
StatePublished - Feb 23 2018
Externally publishedYes


  • E-AB
  • aptamer
  • chronoamperometry
  • electrochemical sensors
  • in vivo
  • precision medicine

ASJC Scopus subject areas

  • Bioengineering
  • Instrumentation
  • Process Chemistry and Technology
  • Fluid Flow and Transfer Processes


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