Spectroelectrochemical testing of a proposed mechanism for a redox-based therapeutic intervention: Ascorbate treatment of severe paraquat poisoning

Zhao, Zhiling; Kim, Eunkyoung; Bentley, William E.; Payne, G. L.

doi:10.1016/j.arres.2023.100068

Cited by 6 publications

(2 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The UV–vis spectrum of the reduced state of Mel-Chit was used as the baseline. The absorbance in Figure a records the differential absorbance at 570 nm (A 570) relative to the baseline [note: the y -axis for absorbance is inverted to facilitate comparison with electrical output] . While the control Gr-Chit shows no oscillations in the absorbance output (Δ A Gr‑Chit ; ∼0), the Mel-Gr-Chit shows a repeated oscillating absorbance output (Δ A Mel‑Gr‑Chit ; 0.0094 ± 0.0006).…”

Section: Resultsmentioning

confidence: 99%

“…Figure d shows additional phase-plane plots using the first derivative of the electrical and optical output signals. , The first derivative of the electrical charge is the current, which is the rate that electrons are being transferred to/from melanin, while the first derivative of absorbance indicates the rate of redox-state switching of the melanin. These first-derivative phase-plane plots in Figure d show similar features between the electrical and optical outputs, which further supports the correlation between the electron flow to/from the film and the molecular switching for BSF melanin.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Operando Spectroelectrochemical Characterization Shows that the Dynamic Flow of Electrons through Melanin Involves Its Redox-State Switching

Kim,

Chen,

Phua

et al. 2023

J. Phys. Chem. C

Self Cite

View full text Add to dashboard Cite

Melanin is a group of heterogeneous polymeric pigments that has been proposed to perform various biological functions and is attracting increasing technological interest as a sustainable electronic material for energy storage and bioelectronics. Here, we prepared a semitransparent hydrogel film from a soluble melanin obtained from the black soldier fly (Hermetia illucens; BSF) and applied an operando spectroelectrochemical approach to investigate the molecular-level changes that occur when electrons are “flowing” through this melanin (i.e., while electron transfer processes are “in operation”). Like other natural and synthetic melanins, we observed that the BSF melanin has reversible redox activities in the mid-physiological redox potential range. We report that electron transfer can occur through an indirect (mediator-based) mechanism and also through a direct mechanism involving an extrinsic electron exchange with conducting graphene. In both mechanisms, we show that electron transfer is correlated to a reversible switching of the melanin’s redox state. Finally, we provide evidence to support a chemical disorder model, which suggests that the properties of melanin may involve diverse structural and mechanistic features that occur over various length scales. Overall, we show that operando spectroelectrochemical measurements can bridge traditional bottom-up and top-down methods to facilitate the characterization of melanin.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%