Axially paraben substituted silicon(IV) phthalocyanines towards dental pathogen Streptococcus mutans: Synthesis, photophysical, photochemical and in vitro properties

• Synthesis and fully characterization of a series of silicon(IV) phthalocyanines as antimicrobial photosensitizers.
• Investigation of absorption, fluorescence, singlet oxygen generation and photodegradation properties.
• Time-resolved fluorescence studies.
• Antibacterial photodynamic efficacy studies against pathogenic bacterium Streptococcus mutans.

A series of silicon(IV) phthalocyanines axially substituted with methylparaben, ethylparaben, propylparaben and butylparaben groups were synthesized and studied as photosensitizers for antimicrobial photodynamic therapy. The absorption, fluorescence, photodegradation and singlet oxygen generation properties of the synthesized Si(IV) phthalocyanines were studied. In vitro antibacterial photodynamic therapy was investigated against cariogenic pathogenic bacterium Streptococcus mutans. Axially propylparaben substituted Si(IV) phthalocyanine showed significant photodynamic efficacy (log 4) at concentration of 10 μM and mild irradiation (60 mW cm−2, 50 J cm−2, LED 637 nm). The low inactivation capacity was observed for the other studied Si(IV) phthalocyanines. The uptake and localization properties of axially propylparaben substituted Si(IV) phthalocyanine showed a sufficient level of accumulation in planktonic cultured bacterium and a complete penetration depth into the biomass of the 48-h bacterial biofilm.

A series of silicon(IV) phthalocyanines axially substituted with paraben derivatives were synthesized and the antibacterial photodynamic efficacy of these compounds were evaluated against pathogenic bacterium Streptococcus mutans.Figure optionsDownload as PowerPoint slide