A combination of biomedical and technological applications is generating, over the past decades, the wellestablished interest toward melanins and melanogenesis. Several compounds have been explored to promote/catalyze oxidative polymerization of melanogenic precursors, such as 5,6-dihydroxyindole-2-carboxylic acid (DHICA), to melanin-like biopolymers in vitro. TiO2 has shown a photocatalytic activity driving DHICA polymerization and leading to the formation of melanin−TiO2 hybrid nanostructures with unique biocide behavior even under visible light. However, the mechanism of melanin formation in those hybrids is not yet well understood although a ligand to metal charge transfer (LMCT) process involving DHICA and Ti4+ ions was hypothesized. Here, we focus on melanin formation and apply a complementary analysis, by using photoluminescence (PL), UV−vis, electron paramagnetic resonance (EPR), and nuclear magnetic resonance (NMR) spectroscopy to reveal the mechanism of DHICA polymerization in the presence of a TiO2-sol. This study discloses TiO2 potentialities to drive and template DHICA polymerization to melanin via LMCT-based photo-oxidative process.

5,6-Dihydroxyindole-2-carboxylic Acid-TiO2 Charge Transfer Complexes in the Radical Polymerization of Melanogenic Precursor(s) / Vitiello, Giuseppe; Pezzella, Alessandro; Calcagno, Vincenzo; Silvestri, Brigida; Raiola, LUCA VITTORIO; D'Errico, Gerardino; Costantini, Aniello; Branda, Francesco; Luciani, Giuseppina. - In: JOURNAL OF PHYSICAL CHEMISTRY. C. - ISSN 1932-7447. - 120:11(2016), pp. 6262-6268. [10.1021/acs.jpcc.6b00226]

5,6-Dihydroxyindole-2-carboxylic Acid-TiO2 Charge Transfer Complexes in the Radical Polymerization of Melanogenic Precursor(s)

VITIELLO, GIUSEPPE;PEZZELLA, ALESSANDRO;CALCAGNO, VINCENZO;SILVESTRI, BRIGIDA;RAIOLA, LUCA VITTORIO;D'ERRICO, GERARDINO;COSTANTINI, ANIELLO;BRANDA, FRANCESCO;LUCIANI, GIUSEPPINA
2016

Abstract

A combination of biomedical and technological applications is generating, over the past decades, the wellestablished interest toward melanins and melanogenesis. Several compounds have been explored to promote/catalyze oxidative polymerization of melanogenic precursors, such as 5,6-dihydroxyindole-2-carboxylic acid (DHICA), to melanin-like biopolymers in vitro. TiO2 has shown a photocatalytic activity driving DHICA polymerization and leading to the formation of melanin−TiO2 hybrid nanostructures with unique biocide behavior even under visible light. However, the mechanism of melanin formation in those hybrids is not yet well understood although a ligand to metal charge transfer (LMCT) process involving DHICA and Ti4+ ions was hypothesized. Here, we focus on melanin formation and apply a complementary analysis, by using photoluminescence (PL), UV−vis, electron paramagnetic resonance (EPR), and nuclear magnetic resonance (NMR) spectroscopy to reveal the mechanism of DHICA polymerization in the presence of a TiO2-sol. This study discloses TiO2 potentialities to drive and template DHICA polymerization to melanin via LMCT-based photo-oxidative process.
2016
5,6-Dihydroxyindole-2-carboxylic Acid-TiO2 Charge Transfer Complexes in the Radical Polymerization of Melanogenic Precursor(s) / Vitiello, Giuseppe; Pezzella, Alessandro; Calcagno, Vincenzo; Silvestri, Brigida; Raiola, LUCA VITTORIO; D'Errico, Gerardino; Costantini, Aniello; Branda, Francesco; Luciani, Giuseppina. - In: JOURNAL OF PHYSICAL CHEMISTRY. C. - ISSN 1932-7447. - 120:11(2016), pp. 6262-6268. [10.1021/acs.jpcc.6b00226]
File in questo prodotto:
File Dimensione Formato  
5,6-Dihydroxyindole-2-carboxylic Acid−TiO2 Charge Transfer Complexes .pdf

solo utenti autorizzati

Tipologia: Versione Editoriale (PDF)
Licenza: Accesso privato/ristretto
Dimensione 1.99 MB
Formato Adobe PDF
1.99 MB Adobe PDF   Visualizza/Apri   Richiedi una copia

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/11588/658665
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 37
  • ???jsp.display-item.citation.isi??? 36
social impact