A Versatile Redox Responsive Nanoferrogels Based Sensor for Metabolics Analytics

Samuel Mugo, Physical Sciences, MacEwan University, Edmonton, Canada (mugos@macewan.ca)
Weihao Lu, Physical Sciences, Macewan University, Edmonton, Canada
Nicole Funk, Physical Sciences, Macewan University, Edmonton, Canada

Developed is an inexpensive label free redox responsive nanoferrogel molecular receptor integrated in a chemoresisistive sensor for rapid detection of Reactive Oxygen Species (ROS) such as H₂O₂ and H₂O₂ deriving metabolites, species are of interest in myriad applications including clinical, environmental, food, and plant physiology.

Inexpensively fashioned by contact printing of redox responsive poly(N-isopropylacrylamide hydrogels herewith called ‘nanoferrogel’ on a conductive nanocellulose paper aerogel, the sensor is designed for specimen surface attachment as wearables, non-invasive transdermal sensors, and can be configured as microneedle sensor for in vivo analysis. Operating via ROS oxidation of the nanoferrogel trapped in the conductive aerogel film, the oxidized nanoferrogel volume change results in an overall change in conductivity, linearly proportional to ROS/ROS deriving metabolite concentration.

In the presentation, the responsivity of the nanoferrogel to different ROS species such as H₂O₂, oxylipin, antioxidants will be demonstrated. The nanoferrogel based H₂O₂ sensor figures of merit, featuring, rapid (≤ 1min) H₂O₂ response, high selectivity, low limits of detection (≤ 0.01 µM),and broad linear dynamic range of (≤ 0.03 µM to ≥ 1.5M) will be highlighted. The nanoferrogel is perfectly recyclable, by electrochemical regeneration, affording ≥ 15 multiple usable cycles.

Also showcased will be the adaptability of nanoferrogel for different sensor design configurations (e.g. micro/nanoelectrode systems), with some preliminary data attesting to the sensors utility for fundamental studies and detection of efflux of endogenous and exogenous H₂O₂ in single cells and other redox biomolecules, (e.g. glucose, choline).

Preliminarily the sensor can be used for detection of bacterial (model used in our study Escherichia coli) autoinducers and metabolites, of importance in bacterial communication-quorum sensing. This would be a useful platform for understanding bacterial biofilm formation.  Further, the nanoferrogel sensor fashioned for utility as a wearable device for detection of redox potential and inherent sweat metabolites will be demonstrated. 

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Short Biography of Presenting Author

Prof. Samuel Mugo is an Associate Professor in Analytical Chemistry at MacEwan University, Edmonton, Canada. Mugo research is focused on integrating multiresponsive (especially pH, redox, ionic strength) polymer nanomaterials as molecular receptors for fabrication of inexpensive and portable chemical sensors for precision agriculture, environmental monitoring and noninvasive wearables for health/wellness applications. The polymer nanomaterials are also explored for molecules (pharmaceuticals, herbicides, nutraceuticals etc.) encapsulation and controlled release.