Photodynamic antibacterial chemotherapy activities of P(V) and Ga(III) triarylcorroles and their silver nanoparticle conjugates

Silver nanoparticle (AgNP) conjugates of two series of P(V) and Ga(III) corroles with 4-thiomethylphenyl- (1-P V Cor-AgNPs and 1-Ga III Cor-AgNPs), thien-3-yl- (2-P V Cor-AgNPs and 2-Ga III Cor-AgNPs), thien-2-yl- (3-P V Cor-AgNPs and 3-Ga III Cor-AgNPs) and 5-bromothien-2-yl- (4-P V Cor-AgNPs and 4-Ga III Cor-AgNPs) meso-aryl rings have been synthesized and characterized, so that their in vitro photodynamic antimicrobial chemotherapy (PACT) properties could be investigated against S. aureus and E. coli. The 4-P V Cor and 4-Ga III Cor complexes are reported for the first time in this context, while 1-3-P V Corr and 1-3-Ga III Cor were reported previously during a study of the photodynamic therapy (PDT) activity properties of their gold nanoparticle conjugates against MCF-7 breast cancer cells. The heavy atom effects of the bromine atoms result in increases in the singlet oxygen quantum yield values for 4-P V Cor and 4-Ga III Cor to 0.59 and 0.72, respectively, from 0.47 and 0.69 for 3-P V Cor and 3-Ga III Cor. Conjugation to the AgNPs results in further slight increases due to an external heavy atom effect and significantly enhances the photostability of the dyes. 1-4-P V Cor were found to have higher PACT activities than 1-4-Ga III Cor due to lower aggregation effects since there is trans-axial ligation. Complete eradication of the E. coli and a Log[Formula: see text] reduction of 7.04 was achieved with 20μg.mL[Formula: see text] of 3-4-P V Cor-AgNPs and 3-4-Ga III Cor-AgNPs despite the difficulties that are typically encountered in this context with Gram-([Formula: see text] bacteria.