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Communication Dans Un Congrès Année : 2023

Comparative study of indocyanine green and an indocyanine green dimer as photothermal agents

Résumé

Indocyanine green (ICG) is a famous FDA-approved fluorescent marker used in medical diagnosis. ICG is characterized by an intense light absorption which fall within the in vivo ‘transparent’ window (700-900 nm), making it ideal for applications in photothermal therapy (PTT). The problem liked to ICG is its high photochemical and chemical instability and its very short effective half-live in circulation (120-240 s)1,2 which sorely hamper its application in PTT. Within this work, we explored the potential of a covalent dimeric form of ICG (dICG) as PTT agent. dICG which could be efficiently prepared by light and oxygen- promoted ICG dimerization in water was studied in terms of optical and photothermal properties. dICG shows drastically reduced fluorescence properties compared to ICG, due to intramolecular resonance energy transfer. However, its photothermal conversion efficiency (PCE) is enhanced and its photobleaching propensity is reduced. The thermal expansion produced during PTT also generates photoacoustic waves which can be used for photoacoustic imaging (PAI), in a theranostic approach. Thus, the photoacoustic amplitude of ICG and dICG in solution was studied, reporting a better photoacoustic performance for dICG. In vitro, both molecules proved to be non-toxic in FaDu pharynx squamous cell carcinoma cells under dark conditions. Hence, our results reveal dICG as a promising PTT/PAI agent. However, as a small molecule, it biodistribution to tumour maybe be ineffective. Therefore, the nanoformulation of dICG was here investigated as an additional mean to improve dICG bioavailability. Both ICG and dICG molecules, were formulated in polyion complex (PIC) coacervates, using a double hydrophilic block copolymer built of a poly(2-alky)-oxazoline (PAOx) chain linked to a positively charged poly-Lornithine (PLO) segment. The electrostatic interaction between the PLO with the negatively charged ICG or dICG drove the formation of nanosized PICs. PICs were stable over time in water, PBS and in presence of increasing salt concentration, while maintaining the good performances in PTT.

Domaines

Chimie
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Dates et versions

hal-04474310 , version 1 (23-02-2024)

Identifiants

  • HAL Id : hal-04474310 , version 1

Citer

Aixa Maria Aguilera Garrido, Marie Millard, Lise Picquoin, Mathilde Bouché, Nadia Canilho, et al.. Comparative study of indocyanine green and an indocyanine green dimer as photothermal agents. 20th Congress of the European Society for Photobiology, Aug 2023, Lyon, France. ⟨hal-04474310⟩
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