Information processing through a bio-based redox capacitor: signatures for redox-cycling.
Redox-cycling compounds can significantly impact biological systems and can be responsible for activities that range from pathogen virulence and contaminant toxicities, to therapeutic drug mechanisms. Current methods to identify redox-cycling activities rely on the generation of reactive oxygen species (ROS), and employ enzymatic or chemical methods to detect ROS. Here, we couple the speed and sensitivity of electrochemistry with the molecular-electronic properties of a bio-based redox-capacitor to generate signatures of redox-cycling. The redox capacitor film is electrochemically-fabricated at the electrode surface and is composed of a polysaccharide hydrogel with grafted catechol moieties. This capacitor film is redox-active but non-conducting and can engage diffusible compounds in either oxidative or reductive redox-cycling. Using standard electrochemical mediators ferrocene dimethanol (Fc) and Ru(NH3)6Cl3 (Ru(3+)) as model redox-cyclers, we observed signal amplifications and rectifications that serve as signatures of redox-cycling. Three bio-relevant compounds were then probed for these signatures: (i) ascorbate, a redox-active compound that does not redox-cycle; (ii) pyocyanin, a virulence factor well-known for its reductive redox-cycling; and (iii) acetaminophen, an analgesic that oxidatively redox-cycles but also undergoes conjugation reactions. These studies demonstrate that the redox-capacitor can enlist the capabilities of electrochemistry to generate rapid and sensitive signatures of biologically-relevant chemical activities (i.e., redox-cycling).
Institute for Bioscience and Biotechnology Research, University of Maryland, College Park, MD 20742, USA; Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA.
Yi
Y
Liu
Institute for Bioscience and Biotechnology Research, University of Maryland, College Park, MD 20742, USA; Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA.
Eunkyoung
E
Kim
Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA; Institute for Systems Research, University of Maryland, College Park, MD 20742, USA.
Ian M
IM
White
Institute for Bioscience and Biotechnology Research, University of Maryland, College Park, MD 20742, USA; Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA.
William E
WE
Bentley
Institute for Bioscience and Biotechnology Research, University of Maryland, College Park, MD 20742, USA; Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, USA. Electronic address: gpayne@umd.edu.
Gregory F
GF
Payne
D000082:Acetaminophen / Q000737:chemistry*; D001205:Ascorbic Acid / Q000737:chemistry*; D015374:Biosensing Techniques; D055664:Electrochemical Techniques; D004566:Electrodes; D005296:Ferrous Compounds / Q000737:chemistry; D010084:Oxidation-Reduction; D011710:Pyocyanine / Q000737:chemistry*; D017382:Reactive Oxygen Species / Q000032:analysis*; D017975:Ruthenium Compounds / Q000737:chemistry; D013816:Thermodynamics
D005296:Ferrous Compounds; D017382:Reactive Oxygen Species; D017975:Ruthenium Compounds; C071550:ferrocenemethanol; D000082:Acetaminophen; D011710:Pyocyanine; D001205:Ascorbic Acid
Biofabrication; Chitosan; Electrodeposition; Redox-cycling; Signal processing