Probing eumelanin photoprotection using a catechol:quinone heterodimer model system

Grieco, Christopher; Empey, Jennifer M; Kohl, Forrest R; Kohler, Bern

doi:10.1039/c8fd00231b

Cited by 12 publications

(23 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Bleaching of the vibrational bands of multiple interacting molecules is also illustrated by the TRIR spectrum of the concentrated Cat+Quin mixture, where preferential excitation of Quin in Cat:Quin complexes leads to bleaching of vibrational modes of both Cat and Quin molecules (Fig. 2f ) 21 .…”

Section: Discussionmentioning

confidence: 86%

“…For the spectrum of the concentrated mixture (Fig. 2d ), the 387 nm band due to Quin broadens and redshifts to 400 nm, which results from hydrogen bonding between Cat and Quin molecules 21 .…”

Section: Resultsmentioning

confidence: 98%

“…2a . These molecules model the dihydroxy and quinone functional groups present in eumelanin 21 . Cat and Quin self-associate to yield hydrogen-bonded heterodimers (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Cat and Quin self-associate to yield hydrogen-bonded heterodimers (Fig. 2b ) when their concentrations in cyclohexane are sufficiently high 21 . Here, we study both a dilute (Fig.…”

Section: Resultsmentioning

confidence: 99%

See 3 more Smart Citations

Probing the heterogeneous structure of eumelanin using ultrafast vibrational fingerprinting

et al. 2020

Self Cite

View full text Add to dashboard Cite

Eumelanin is a brown-black biological pigment with sunscreen and radical scavenging functions important to numerous organisms. Eumelanin is also a promising redox-active material for energy conversion and storage, but the chemical structures present in this heterogeneous pigment remain unknown, limiting understanding of the properties of its light-responsive subunits. Here, we introduce an ultrafast vibrational fingerprinting approach for probing the structure and interactions of chromophores in heterogeneous materials like eumelanin. Specifically, transient vibrational spectra in the double-bond stretching region are recorded for subsets of electronic chromophores photoselected by an ultrafast excitation pulse tuned through the UV-visible spectrum. All subsets show a common vibrational fingerprint, indicating that the diverse electronic absorbers in eumelanin, regardless of transition energy, contain the same distribution of IR-active functional groups. Aggregation of chromophores diverse in oxidation state is the key structural property underlying the universal, ultrafast deactivation behavior of eumelanin in response to photoexcitation with any wavelength.

show abstract

Section: Discussionmentioning

confidence: 86%

Section: Resultsmentioning

confidence: 98%

“…2a . These molecules model the dihydroxy and quinone functional groups present in eumelanin 21 . Cat and Quin self-associate to yield hydrogen-bonded heterodimers (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Cat and Quin self-associate to yield hydrogen-bonded heterodimers (Fig. 2b ) when their concentrations in cyclohexane are sufficiently high 21 . Here, we study both a dilute (Fig.…”

Section: Resultsmentioning

confidence: 99%

See 2 more Smart Citations

Probing the heterogeneous structure of eumelanin using ultrafast vibrational fingerprinting

et al. 2020

Self Cite

View full text Add to dashboard Cite

show abstract

“…In addition to polydopamine, other polymer models mimicking natural melanin are being investigated as catechol/quinone heterodimers [49], but they clearly belong to the photoprotectors obtained by chemical synthesis rather than by natural means.…”

Section: Natural Compounds Related To Animal Melaninmentioning

confidence: 99%

Photoprotection and Skin Pigmentation: Melanin-Related Molecules and Some Other New Agents Obtained from Natural Sources

2020

View full text Add to dashboard Cite

Direct sun exposure is one of the most aggressive factors for human skin. Sun radiation contains a range of the electromagnetic spectrum including UV light. In addition to the stratospheric ozone layer filtering the most harmful UVC, human skin contains a photoprotective pigment called melanin to protect from UVB, UVA, and blue visible light. This pigment is a redox UV-absorbing agent and functions as a shield to prevent direct UV action on the DNA of epidermal cells. In addition, melanin indirectly scavenges reactive oxygenated species (ROS) formed during the UV-inducing oxidative stress on the skin. The amounts of melanin in the skin depend on the phototype. In most phenotypes, endogenous melanin is not enough for full protection, especially in the summertime. Thus, photoprotective molecules should be added to commercial sunscreens. These molecules should show UV-absorbing capacity to complement the intrinsic photoprotection of the cutaneous natural pigment. This review deals with (a) the use of exogenous melanin or melanin-related compounds to mimic endogenous melanin and (b) the use of a number of natural compounds from plants and marine organisms that can act as UV filters and ROS scavengers. These agents have antioxidant properties, but this feature usually is associated to skin-lightening action. In contrast, good photoprotectors would be able to enhance natural cutaneous pigmentation. This review examines flavonoids, one of the main groups of these agents, as well as new promising compounds with other chemical structures recently obtained from marine organisms.

show abstract

Hydrogel Patterning with Catechol Enables Networked Electron Flow

Zhao

Rzasa

et al. 2021

Adv Funct Materials

View full text Add to dashboard Cite

Reduction–oxidation (redox) reactions provide a distinct modality for biological communication that is fundamentally different from the more‐familiar ion‐based electrical modality. Biology uses these two modalities for communication through different systems (immune versus nervous), and uses different mechanisms to control the flow of the charge carriers: the flow of soluble ions is controlled using structural barriers (i.e., membranes) and gates (e.g., membrane‐spanning protein channels), while the flow of insoluble electrons is controlled using redox‐reaction networks. Here, a simple electrochemical approach to pattern catechols onto a flexible polysaccharide hydrogel is reported and it is demonstrated that the patterned catechol regions serve as nodes for the mediated flow of electrons through redox reactions. Electron flow through this node involves the switching of binary redox states (oxidized and reduced) and this node's redox state can be detected (i.e., “read”) by passively observing its optical absorbance, or actively switching its redox‐state electrochemically. Further, this catechol node can be switched through biological mechanisms, and this enables the fabricated catechol node to be embedded within biochemical redox reaction networks to facilitate the spanning of bio‐electronic communication. Thus, it is envisioned that catechols can emerge as a molecular equivalent to a transistor for miniaturize‐able, deployable and sustainable redox‐linked bioelectronics.

show abstract

Probing eumelanin photoprotection using a catechol:quinone heterodimer model system

Abstract: Here, we investigate the photochemistry of a catechol : o-quinone heterodimer as a model system for uncovering the photoprotective roots of eumelanin.

Cited by 12 publications

References 40 publications

Probing the heterogeneous structure of eumelanin using ultrafast vibrational fingerprinting

Probing the heterogeneous structure of eumelanin using ultrafast vibrational fingerprinting

Photoprotection and Skin Pigmentation: Melanin-Related Molecules and Some Other New Agents Obtained from Natural Sources

Hydrogel Patterning with Catechol Enables Networked Electron Flow

Contact Info

Product

Resources

About