Highly Emissive Biological Bilirubin Molecules: Shedding New Light on the Phototherapy Scheme - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of Physical Chemistry B Année : 2021

Highly Emissive Biological Bilirubin Molecules: Shedding New Light on the Phototherapy Scheme

Résumé

Bilirubin (BR) is the main end-product of the hemoglobin catabolism. For decades, its photophysics has been mainly discussed in terms of ultrafast deactivation of the excited state in solution, where, indeed, BR shows a very low green emission quantum yield (EQY), 0.03%, resulting from an efficient nonradiative isomerization process. Herein, we present, for the first time, unique and exceptional photophysical properties of solid-state BR, which amend by changing the type of crystal, from a closely packed α crystal to an amorphous loosely packed β crystal. BR α crystals show a very bright red emission with an EQY of ca. 24%, whereas β crystals present, in addition, a low green EQY of ca. 0.5%. By combining density functional theory (DFT) calculations and time-resolved emission spectroscopy, we trace back this dual emission to the presence of two types of BR molecules in the crystal: a “stiff” monomer, M1, distorted by particularly strong internal H-bonds and a “floppy” monomer, M2, having a structure close to that of BR in solution. We assign the red strong emission of BR crystals to M1 present in both the α and β crystals, while the low green emission, only present in the amorphous (β) crystal, is interpreted as M2 emission. Efficient energy-transfer processes from M2 to M1 in the closely packed α crystal are invoked to explain the absence of the green component in its emission spectrum. Interestingly, these unique photophysical properties of BR remain in polar solvents such as water. Based on these unprecedented findings, we propose a new model for the phototherapy scheme of BR inside the human body and highlight the usefulness of BR as a strong biological fluorescent probe.
Fichier principal
Vignette du fichier
Highly Emissive Biological Bilirubin Molecules- A new model for the Phototherapy Scheme_Final_MP_VDC.pdf (5.8 Mo) Télécharger le fichier

Dates et versions

hal-03419821 , version 1 (08-11-2021)

Licence

Paternité

Identifiants

Citer

Ahmed El-Zohry, Valentin Diez-Cabanes, Mariachiara Pastore, Taha Ahmed, Burkhard Zietz. Highly Emissive Biological Bilirubin Molecules: Shedding New Light on the Phototherapy Scheme. Journal of Physical Chemistry B, 2021, 125 (32), pp.9213-9222. ⟨10.1021/acs.jpcb.1c05308⟩. ⟨hal-03419821⟩
7 Consultations
10 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More