Wireless Monitoring of Small Molecules on a Freely-Moving Animal using Electrochemical Aptamer Biosensors

Abstract

This paper introduces a wireless electrochemical sensing system for in vivo small-molecule sensing using reagent-less structure-switching aptamers. The system consists of a 65-nm CMOS electrochemical sensing circuit with an on-chip waveform generator, a Bluetooth microcontroller (MCU), and a battery, which allow for robust wireless recording in a freely moving animal. The device can perform data acquisition every 10 seconds, including wireless data transfer, and consumes an average current of 3mA after duty cycling. Multiple steps in the data processing for noise reduction are discussed. Real-time sensing of infused kanamycin concentration in the interstitial fluids (ISF) using "wire" electrodes is demonstrated on a freely moving rat with the device implanted under the skin. The paper also compares the results at different sensing locations and identifies the difference in their diffusion rates. Finally, the authors suggest that the technology can be adapted for monitoring other molecules using DNA aptamers of different sequences.

Wireless Monitoring of Small Molecules in a Freely Moving Animal using Electrochemical Aptamer Biosensors

“…This paper builds upon our previous work in [33] and [34]. In Section II, we provide a detailed discussion of our wireless readout system, which includes the design of circuits, the preparation of functionalized electrodes, and device assembly before animal implantation.…”

Effects of storage conditions on the performance of an electrochemical aptamer-based sensor

“…Using such sensors, we and others have achieved sub-second resolution in the measurement of drugs, metabolites, and other small molecules over the course of hours in situ in the blood, brains, and peripheral tissues of live animals. [10][11][12][13][14][15][16] Despite this advantage, shelf-life remains a relatively underexplored and potentially serious obstacle to the wide-spread use of EAB sensors. Specifically, we have historically fabricated EAB sensors and used them within 24 h rather than manufacturing them in bulk for future use.…”