Theoretical and experimental studies concerning monomer/aggregates equilibrium of zinc phthalocyanine for future photodynamic action

Author(s)

Calori, Italo Rodrigo ^[1] ; Jayme, Cristiano Ceron ^{[1, 2]} ; Ueno, Leonardo Tsuyoshi ^[3] ; Correto Machado, Francisco Bolivar ^[3] ; Tedesco, Antonio Claudio ^{[1, 2]}

Affiliation

^[1] Univ Sao Paulo, Fac Philosophy Sci & Letters Ribeirao Preto, Ctr Nanotechnol & Tissue Engn, Dept Chem, Photobiol & Photomed Res Grp, BR-14040901 Ribeirao Preto, SP - Brazil

^[2] Univ Sao Paulo, Sch Pharmaceut Sci Ribeirao Preto, BR-14040901 Ribeirao Preto, SP - Brazil

^[3] Inst Tecnol Aeronaut, Dept Quim, Comando Geral Tecnol Aeroespacial, BR-12228900 Sao Jose Dos Campos, SP - Brazil

• Document type: Journal article
• Source: SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY; v. 214, p. 513-521, MAY 5 2019.
• Web of Science Citations: 0

Abstract

Monomeric zinc phthalocyanine has been studied as a promising active photosensitizer in photodynamic therapy against cancer, in which its aggregate form is non-active. This paper aimed to describe the monomer/aggregates equilibrium of zinc phthalocyanine in binary water/DMSO mixtures. To reach this aim theoretical calculation, electronic absorption, static and time-resolved fluorescence, and resonance light scattering was used. Zinc phthalocyanine shows a complex water dependence behavior in the mixture. At least three distinct steps were observed: (i) until 30% water zinc phthalocyanine is essentially in the monomeric form, changing to (ii) small slipped cofacial-aggregates around 30% to 40% water and finally to (iii) a staircase arrangement of large aggregates at higher water percent. The staircase arrangement is driven by the intermolecular coordination between the pyrrolic nitrogen lone-pairs and the central metal zinc. The water-Zn coordination governs the fluorescence quenching by a static mechanism. These results have direct relevance in the better understanding on the behavior of zinc phthalocyanine in vivo and when incorporated in drug delivery systems for clinical applications in photodynamic therapy. (C) 2019 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 18/10237-1 - Development and characterization of scaffolds based on PCL-PGE and DNA applied to tissue engineering for bone regeneration
• Grantee: Cristiano Ceron Jayme
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 13/50181-1 - Use of drugs containing nanocarriers with photosensitizers and/or other active compounds applied to cell therapy and treatment of central nervous system disorders
• Grantee: Antonio Claudio Tedesco
• Support Opportunities: Research Projects - Thematic Grants