In Vivo Plant Bio-Electrochemical Sensor Using Redox Cycling.
Tali DotanAakash JogKian Kadan-JamalAdi AvniYosi Shacham-DiamandPublished in: Biosensors (2023)
This work presents an in vivo stem-mounted sensor for Nicotiana tabacum plants and an in situ cell suspension sensor for Solanum lycopersicum cells. Stem-mounted sensors are mechanically stable and less sensitive to plant and air movements than the previously demonstrated leaf-mounted sensors. Interdigitated-electrode-arrays with a dual working electrode configuration were used with an auxiliary electrode and an Ag/AgCl quasi-reference electrode. Signal amplification by redox cycling is demonstrated for a plant-based sensor responding to enzyme expression induced by different cues in the plants. Functional biosensing is demonstrated, first for constitutive enzyme expression and later, for heat-shock-induced enzyme expression in plants. In the cell suspension with redox cycling, positive detection of the enzyme β-glucuronidase (GUS) was observed within a few minutes after applying the substrate (pNPG, 4-Nitrophenyl β-D-glucopyranoside), following redox reactions of the product (p-nitrophenol (pNP)). It is assumed that the initial reaction is the irreversible reduction of pNP to p-hydroxylaminophenol. Next, it can be either oxidized to p-nitrosophenol or dehydrated and oxidized to aminophenol. Both last reactions are reversible and can be used for redox cycling. The dual-electrode redox-cycling electrochemical signal was an order of magnitude larger than that of conventional single-working electrode transducers. A simple model for the gain is presented, predicting that an even larger gain is possible for sub-micron electrodes. In summary, this work demonstrates, for the first time, a redox cycling-based in vivo plant sensor, where diffusion-based amplification occurs inside a tobacco plant's tissue. The technique can be applied to other plants as well as to medical and environmental monitoring systems.
Keyphrases
- carbon nanotubes
- high intensity
- poor prognosis
- electron transfer
- label free
- heat shock
- solid state
- single cell
- gold nanoparticles
- oxidative stress
- cell therapy
- stem cells
- cell wall
- mesenchymal stem cells
- heat shock protein
- induced apoptosis
- endothelial cells
- high resolution
- risk assessment
- cell death
- nucleic acid
- climate change
- sensitive detection
- reduced graphene oxide
- high density
- diabetic rats
- life cycle