Bio-Inspired Carbon Monoxide Sensors with Voltage-Activated Sensitivity

Article abstract of DOI:10.1002/anie.201707491

Carbon monoxide (CO) outcompetes oxygen when binding to the iron center of hemeproteins, leading to a reduction in blood oxygen level and acute poisoning. Harvesting the strong specific interaction between CO and the iron porphyrin provides a highly selective and customizable sensor. We report the development of chemiresistive sensors with voltage-activated sensitivity for the detection of CO comprising iron porphyrin and functionalized single-walled carbon nanotubes (F-SWCNTs). Modulation of the gate voltage offers a predicted extra dimension for sensing. Specifically, the sensors show a significant increase in sensitivity toward CO when negative gate voltage is applied. The dosimetric sensors are selective to ppm levels of CO and functional in air. UV/Vis spectroscopy, differential pulse voltammetry, and density functional theory reveal that the in situ reduction of Fe^III to Fe^II enhances the interaction between the F-SWCNTs and CO. Our results illustrate a new mode of sensors wherein redox active recognition units are voltage-activated to give enhanced and highly specific responses.

Full text of DOI:10.1002/anie.201707491

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A Journal of the Gesellschaft Deutscher Chemiker
Angewandte
Chemie
International Edition
www.angewandte.org
Accepted Article
Title: Bio-Inspired Carbon Monoxide Sensors with Voltage-Activated
Sensitivity
Authors: Timothy M. Swager, Suchol Savagatrup, Vera Schröder, Xin
He, Sibo Lin, Maggie He, Omar Yassine, Khaled N Salama,
and Xi Xiang Zhang
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To be cited as: Angew. Chem. Int. Ed. 10.1002/anie.201707491
Angew. Chem. 10.1002/ange.201707491
Link to VoR: http://dx.doi.org/10.1002/anie.201707491
http://dx.doi.org/10.1002/ange.201707491

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10.1002/anie.201707491
Angewandte Chemie International Edition
Bio-Inspired Carbon Monoxide Sensors with Voltage-Activated Sensitivity
Suchol Savagatrup a, †, Vera Schroeder a, †, Xin He b, Sibo Lin a, Maggie He a, Omar Yassine c,
Khaled N. Salama c, Xi-Xiang Zhang b, and Timothy M. Swager a, *
a Department of Chemistry and Institute for Soldier Nanotechnologies, Massachusetts Institute of
Technology, 77 Massachusetts Avenue, Cambridge Massachusetts 02139, United States
b Physical Science and Engineering Division, King Abdullah University of Science and
Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
c Sensors Lab, Division of Computer, Electrical and Mathematical Science and Engineering,
King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi
Arabia
*Author to whom correspondence should be addressed: tswager@mit.edu
† Equal contributions
Keywords: Carbon monoxide, sensors, carbon nanotubes, iron porphyrin, voltage-activated
1
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10.1002/anie.201707491
Angewandte Chemie International Edition
COMMUNICATION
Revving up for sensing: We
developed a platform for voltage-
Suchol Savagatrup †, Vera
Schroeder †, Xin He, Sibo Lin,
Maggie He, Omar Yassine, Khaled
N. Salama, Xi-Xiang Zhang, and
Timothy M. Swager *
activated,
chemiresistive
gas
detection based on covalently
functionalized single-walled carbon
nanotubes (SWCNTs) decorated
with voltage-responsive chemical
selectors. The sensor is highly
selective towards CO over oxygen,
nitrogen, and carbon dioxide and is
robust to humidity and remains
operational in air.
Page No. – Page No.
Bio-Inspired Carbon Monoxide
Sensors with Voltage-Activated
Sensitivity
2
This article is protected by copyright. All rights reserved.

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10.1002/anie.201707491
Angewandte Chemie International Edition
Abstract
Carbon monoxide (CO) outcompetes oxygen when binding to the iron center of
hemeproteins, leading to a reduction in blood oxygen level and acute poisoning. Harvesting the
strong specific interaction between CO and the iron porphyrin provides a highly selective and
customizable sensor. We report the development of chemiresistive sensors with voltage-activated
sensitivity for the detection of CO comprising iron porphyrin and functionalized single walled
carbon nanotubes (F-SWCNTs). Modulation of the gate voltage offers a predicted extra dimension
for sensing. Specifically, the sensors show significant increase in sensitivity toward CO when
negative gate voltage is applied. The dosimetric sensors are selective to ppm levels of CO and
functional in air. UV-Vis spectroscopy, differential pulse voltammetry, and density functional
theory reveal that the in situ reduction of FeIII to FeII enhances the interaction between the F-
SWCNTs and CO. Our results illustrate a new mode of sensors wherein redox active recognition
units are voltage-activated to give enhanced and highly specific responses.
Introduction
Carbon monoxide (CO) is responsible for more than half of all fatal poisoning
worldwide.[1] Exposure to the colorless, tasteless, and odorless gas is difficult to discern as the
initial symptoms of poisoning (headache, dizziness, and confusion) are nonspecific. In the United
States, the Occupational Safety and Health Administration (OSHA) has designated permissible
exposure limits of 50 ppm over eight hours and 200 ppm over five minutes.[2] The affinity of iron
porphyrin towards CO is well-documented for the enzymes cytochrome P450,[3–5] hemoglobin,[6]
and myoglobin.[7] This high affinity for CO over O2 of hemoglobin and myoglobin is the
underlying mechanism of carbon monoxide poisoning in mammals.[8,9] Although detectors for CO
3
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