The efficacy of surfactant mixtures of Pluronic ® F127 and Tween 80 at overall concentration in the micromolar range and molar ratio 1:1, 1:10, and 10:1 in inhibiting aggregation of the photosensitizer meso-tetraphenyl chlorin disulphonate (TPCS 2a ) was investigated in aqueous media at pH 2.9 by means of steady-state absorption and fluorescence emission spectroscopy as well as time-resolved fluorescence analysis. Corresponding experiments were performed at pH 7.4 in the absence of surfactants to determine the spectroscopic properties of a monomeric sample. Aggregation resulted in a red shift of the Soret absorption band and in substantial fluorescence quenching. The fluorescence lifetime of TPCS 2a was a particularly sensitive indicator of the aggregation state, as the monomer at pH 7.4 decayed with a ∼ 10 ns time constant, while aggregation resulted in subnanosecond decay. The critical micelle concentration (CMC) of the surfactant mixtures was determined spectrophotometrically in the presence of TPCS 2a . The ability of the surfactant mixtures to prevent aggregation at acidic pH was evaluated at overall surfactant concentration below and above CMC. Solubilization of TPCS 2a in Pluronic ® F127/Tween 80 mixtures prevented aggregation of the photosensitizer at overall surfactant concentrations much lower than those needed for both pure Pluronic ® F127 and pure Tween 80.

Solubilization of the chlorin TPCS 2a in the presence of Pluronic ® F127/Tween 80 mixtures

CUCCATO, NICOLA;Nardo L.;
2019-01-01

Abstract

The efficacy of surfactant mixtures of Pluronic ® F127 and Tween 80 at overall concentration in the micromolar range and molar ratio 1:1, 1:10, and 10:1 in inhibiting aggregation of the photosensitizer meso-tetraphenyl chlorin disulphonate (TPCS 2a ) was investigated in aqueous media at pH 2.9 by means of steady-state absorption and fluorescence emission spectroscopy as well as time-resolved fluorescence analysis. Corresponding experiments were performed at pH 7.4 in the absence of surfactants to determine the spectroscopic properties of a monomeric sample. Aggregation resulted in a red shift of the Soret absorption band and in substantial fluorescence quenching. The fluorescence lifetime of TPCS 2a was a particularly sensitive indicator of the aggregation state, as the monomer at pH 7.4 decayed with a ∼ 10 ns time constant, while aggregation resulted in subnanosecond decay. The critical micelle concentration (CMC) of the surfactant mixtures was determined spectrophotometrically in the presence of TPCS 2a . The ability of the surfactant mixtures to prevent aggregation at acidic pH was evaluated at overall surfactant concentration below and above CMC. Solubilization of TPCS 2a in Pluronic ® F127/Tween 80 mixtures prevented aggregation of the photosensitizer at overall surfactant concentrations much lower than those needed for both pure Pluronic ® F127 and pure Tween 80.
2019
http://www.tandfonline.com/loi/iphd20
Aggregation; critical micelle concentration; meso-tetraphenyl chlorin disulphonate (TPCS ; 2a; ) ; photochemical internalization; photosensitizer; solubilization; surfactant; Poloxamer; Polysorbates; Porphyrins; Solubility; Spectrometry, Fluorescence
Cuccato, Nicola; Nardo, L.; Kristensen, S.; Hjorth Tonnesen, H.; Lilletvedt Tovsen, M.
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11383/2081214
 Attenzione

L'Ateneo sottopone a validazione solo i file PDF allegati

Citazioni
  • ???jsp.display-item.citation.pmc??? 1
  • Scopus 4
  • ???jsp.display-item.citation.isi??? 5
social impact