1. A search for enhanced photodynamic activity against Staphylococcus aureus planktonic cells and biofilms: the evaluation of phthalocyanine–detonation nanodiamond–Ag nanoconjugates
- Author
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Tebello Nyokong, Refilwe Matshitse, and Yolande Ikala Openda
- Subjects
Staphylococcus aureus ,Indoles ,Photosensitizing Agents ,Silver ,Molecular Structure ,Chemistry ,Singlet oxygen ,Biofilm ,Nanoparticle ,chemistry.chemical_element ,Microbial Sensitivity Tests ,Nanoconjugates ,Zinc ,Isoindoles ,Plankton ,Detonation nanodiamond ,Anti-Bacterial Agents ,Nanodiamonds ,chemistry.chemical_compound ,Covalent bond ,Biofilms ,Phthalocyanine ,Physical and Theoretical Chemistry ,Nuclear chemistry - Abstract
The present work reports on the synthesis and characterization of novel zinc (2) and indium (3) 2-amino-4-bromophenoxy substituted phthalocyanines (Pcs) along with the self-assembled nanoconjugates formed via π–π stacking interaction onto detonation nanodiamonds (DNDs) to form 2@DNDs and 3@DNDs. 2@DNDs and 3@DNDs were covalently linked to chitosan–silver mediated nanoparticles (CSAg) to form 2@DNDs-CSAg and 3@DNDs-CSAg nanoconjugates. High singlet oxygen quantum yields in DMSO of 0.69 and 0.72 for Pcs alone and 0.90 and 0.92 for 2@DNDs-CSAg and 3@DNDs-CSAg, respectively, were obtained. The photodynamic antimicrobial chemotherapy (PACT) activity of both phthalocyanines and nanoconjugates was tested against planktonic cells and biofilms of S. aureus. 2@DNDs-CSAg and 3@DNDs-CSAg caused effective killing with a log reduction of 9.74. In addition, PACT studies on single-species S. aureus biofilms were carried out with log reduction values of 5.12 and 5.27 at 200 μg mL−1 for 2@DNDs-CSAg and 3@DNDs-CSAg, respectively.
- Published
- 2020