Bio‐Inspired Carbon Monoxide Sensors with Voltage‐Activated Sensitivity

Abstract

Correspondence to: Timothy M. Swager. + These authors contributed equally to this work.Supporting information and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.org/ 10.1002/anie.201707491. Conflict of interestThe authors declare the following competing financial interest(s): A patent has been filed on this technology. HHS Public Access Author Manuscript Author ManuscriptAuthor Manuscript Author ManuscriptCarbon 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 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 voltageactivated to give enhanced and highly specific responses. CommunicationsRevving up for sensing: A platform for voltage-activated, chemiresistive gas detection has been delveloped based on covalently functionalized single-walled carbon nanotubes decorated with voltage-responsive chemical selectors. The sensor is highly selective towards CO in the presence of oxygen, nitrogen, and carbon dioxide and is robust to humidity and remains operational in air. KeywordsCarbon monoxide; carbon nanotubes; iron porphyrin; sensors; voltage-activated 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][4][5] hemoglobin, [6] and myoglobin. [7] This high affinity for CO over O 2 of hemoglobin and myoglobin is the underlying mechanism of carbon monoxide poisoning in mammals. [8,9] Although detectors for CO are available, there remains a need for massively [16,17] Theoretical and experimental reports have suggested that CO does not engage in charge transfer with pristine SWCNTs, [18][19][20] indicating the a chemical reactive interface is necessary. Conductivity...

Recent Advances in Chemical Sensors Using Porphyrin-Carbon Nanostructure Hybrid Materials

“…The recent developments show that the more traditionally explored systems combining porphyrins with graphene or carbon nanotubes are still valid sensing systems, especially for the electrochemical detection of metal ions (Cd 2+ , Fe 3+ , Zn 2+ [28,33,38]) or compounds of biological relevance in aqueous media [25,[29][30][31]37]. Furthermore, novel configurations in FET devices using porphyrins/CNMs are increasingly used in chemical [43,44] and biological sensors fabrication, the latter commonly exploiting aptamer sensing strategy [35].…”

“…Results showed that the neural model outperformed PLSR obtained satisfactory capacity in accurately predict concentrations. In the case of FET devices, Swager et al found that gate voltage may modulate the sensitivity of sensors based on F-SWCNTs and FeTPPClO 4 , which serves as redox active CO binding site [43]. UV-VIS spectroscopy, differential pulse voltammetry, and density functional theory reveal that the porphyrin is responsible for the in-situ reduction of Fe III to Fe II , which in turn enhances the interaction between the F-SWCNTs and CO. As above mentioned, one of the main novelties of the work is the possibility to modulate (in this case amplifying) the sensitivity to CO when negative gate voltage is applied.…”

Materials, Actuators, and Sensors for Soft Bioinspired Robots

“…[335] With the advancements of technology, developed sensors can accurately and selectively quantify humidity, [336][337][338][339] volatile organic compounds (i.e., ethanol, acetone, methanol, formaldehyde), [313,336,338] and noncondensable gases (i.e., hydrogen, carbon monoxide, carbon dioxide). [340] Humidity sensors have been inspired by weak molecular interactions and bonds [336,337] to the photonic structures of beetle wing-cases. [338,339] Weak noncovalent interactions between proteins and molecules lead to supramolecular assemblies and disassemblies, which can be detected at a cellular level.…”

“…[313] While most of the mentioned gas sensors are quantified through visual observations (i.e., wrinkling, swelling, and color alteration), there are still those whose molecular interactions are measured through circuit resistance. [336,337,340] It was observed that the sensor sensitivity increased through the application of a negative voltage gate, enhancing the interaction of noncondensable gas (i.e., carbon monoxide) with the fabricated sensor con-taining iron porphyrin and functionalized single-walled carbon nanotubes. [340]…”

“…[336,337,340] It was observed that the sensor sensitivity increased through the application of a negative voltage gate, enhancing the interaction of noncondensable gas (i.e., carbon monoxide) with the fabricated sensor con-taining iron porphyrin and functionalized single-walled carbon nanotubes. [340]…”