Self-Powered Electrochemical Lactate Biosensing

Ankit Baingane,Gymama Slaughter

doi:10.3390/en10101582

Abstract

This work presents the development and characterization of a self-powered electrochemical lactate biosensor for real-time monitoring of lactic acid. The bioanode and biocathode were modified with D-lactate dehydrogenase (D-LDH) and bilirubin oxidase (BOD), respectively, to facilitate the oxidation and reduction of lactic acid and molecular oxygen. The bioelectrodes were arranged in a parallel configuration to construct the biofuel cell. This biofuel cell’s current–voltage characteristic was analyzed in the presence of various lactic acid concentrations over a range of 1–25 mM. An open circuit voltage of 395.3 mV and a short circuit current density of 418.8 µA/cm² were obtained when operating in 25 mM lactic acid. Additionally, a 10 pF capacitor was integrated via a charge pump circuit to the biofuel cell to realize the self-powered lactate biosensor with a footprint of 1.4 cm × 2 cm. The charge pump enabled the boosting of the biofuel cell voltage in bursts of 1.2–1.8 V via the capacitor. By observing the burst frequency of a 10 pF capacitor, the exact concentration of lactic acid was deduced. As a self-powered lactate sensor, a linear dynamic range of 1–100 mM lactic acid was observed under physiologic conditions (37 °C, pH 7.4) and the sensor exhibited an excellent sensitivity of 125.88 Hz/mM-cm2. This electrochemical lactate biosensor has the potential to be used for the real-time monitoring of lactic acid level in biological fluids.

Highlights

Organ transplantation is one of the most significant advances achieved in medicine during the latter half of the 20th century and still remains in many cases the only effective therapy for end-stage organ failure
As a self-powered lactate sensor, a linear dynamic range of 1–100 mM lactic acid was observed under physiologic conditions (37 ◦ C, pH 7.4) and the sensor exhibited an excellent sensitivity of 125.88 Hz/mM-cm2
This electrochemical lactate biosensor has the potential to be used for the real-time monitoring of lactic acid level in biological fluids

Summary

Introduction

Organ transplantation is one of the most significant advances achieved in medicine during the latter half of the 20th century and still remains in many cases the only effective therapy for end-stage organ failure. Preservation buys time, which is essential to organize staff and facilities, transport organs, and perform necessary laboratory tests and surgery [1]. There are nearly 2 million people living with extremity limb loss in the United States. The main causes of extremity limb loss have been attributed to vascular disease (54%)—including diabetes and peripheral arterial disease, trauma (45%), and cancer (less than 2%) [2]. The goal of organ preservation is to develop a method to monitor the biomarkers of stress induced by the procurement and preservation process in real-time in order to extend the preservation period to allow for assembly of the surgical team and the transport of the organ between facilities. The typical preservation time for organs is anywhere from 15 to 30 h [3].

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