title: Photoinactivation of Candida albicans and Escherichia coli using aluminium phthalocyanine on gold nanoparticles.
abstract: The conjugates of aluminium phthalocyanine (complex 1) with gold nanorods (complex 1–AuNRs) and bipyramids (complex 1–AuBPs) showed improved singlet oxygen quantum yields of 0.23 and 0.24, respectively, compared to that of complex 1 alone at 0.12. Complex 1 and its conjugates were used for the photoinactivation of fungi (C. albicans) and bacteria cells (E. coli). The Q band absorbances were the same for the Pc alone and when conjugated to AuNPs. The efficiency of these conjugates was evaluated by measuring the log reduction of the microorganisms (C. albicans and E. coli) after irradiation with visible light in the presence of photosensitizers. Aluminium phthalocyanine alone showed log1.78 and log2.51 reductions for C. albicans and E. coli respectively. However, the conjugates showed higher photosensitization with log2.08 and log3.34 for C. albicans and E. coli, respectively using 1–AuBPs. For complex 1–AuNRs log2.53 and log3.71 were achieved for C. albicans and E. coli respectively. The statistical analysis of the results showed that the enhanced photoinactivation observed in both microorganisms was irrespective of the shape of the nanoparticles conjugated. Photoinactivation of C. albicans was less than that of E. coli even though a higher concentration of complex 1 or its conjugates was used in C. albicans.
authors.affiliation: Department of Chemistry, Rhodes University, Grahamstown 6140, South Africa. t.nyokong@ru.ac.za.
authors.forename: Thandekile
authors.initials: T
authors.lastname: Mthethwa
authors.forename: Tebello
authors.initials: T
authors.lastname: Nyokong
mesh_terms: D002176:Candida albicans; D004926:Escherichia coli; D006046:Gold / Q000737:chemistry*; D007211:Indoles / Q000737:chemistry / Q000494:pharmacology*; D053768:Metal Nanoparticles / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry / Q000494:pharmacology*; D010778:Photochemotherapy / Q000379:methods*
chemical_list: D007211:Indoles; D009942:Organometallic Compounds; C060570:aluminum phthalocyanine; D006046:Gold