Dual action of asymmetrical zinc(II) phthalocyanines conjugated to silver tungstate nanoparticles towards photodegradation of tetracycline and inactivation of Staphylococcus aureus bacteria

Asymmetric (A3B) Zn(II) phthalocyanines containing dimethoxy phenoxy as the dominant substituent and (phenoxy) propanoic acid (1), (phenoxy) acetic acid (2), and (phenoxy) acrylic acid (3) as the other substituents were synthesized and linked to silver tungstate nanoparticles (Ag2WO4 NPs). The photocatalytic activities of the prepared complexes 1-3 and nanoconjugates were evaluated for the photodegradation of tetracycline (TC) under visible-light irradiation and for photodynamic antimicrobial chemotherapy (PACT) activity against S. aureus. The results revealed that complex 3 had the best photocatalytic and PACT performance compared to 1 and 2, corresponding to the higher singlet oxygen quantum yield of the former in dimethyl sulfoxide. The photo -degradation reaction was also examined using EPR and a mechanism for generation of singlet oxygen under visible light was confirmed. Photoinactivation of S. aureus improved in the presence of TC, when the two are applied together.

Automated summary

Synthetic compounds of asymmetric (A3B) Zn(II) phthalocyanines with dimethoxy phenoxy as the main substituent and (phenoxy) propanoic acid, (phenoxy) acetic acid, and (phenoxy) acrylic acid as other substituents were linked to silver tungstate nanoparticles. The photocatalytic and photodynamic antimicrobial chemotherapy activities of these compounds were evaluated for the degradation of tetracycline and inactivation of S. aureus under visible light irradiation. The results showed that compound 3 exhibited the best performance, attributed to its higher singlet oxygen quantum yield. The mechanism of singlet oxygen generation under visible light was confirmed using EPR. Furthermore, the photoinactivation of S. aureus was enhanced in the presence of tetracycline.