Biological Effect of Thiazole-Containing Zinc(II) Phthalocyanine on Different Sizes of Gold Nanoparticles

This study aims to design multidisciplinary bioagents for a wide range of biological applications. The synthesis and characterization of 4,5-bis((4-phenylthiazol-2-yl)thio)phthalonitrile (a) and its octa-substituted zinc(II) phthalocyanine derivative (b) were described in this study. Additionally, gold nanoparticles were synthesized in three different sizes, including 10 nm (1), 45 nm (2), and 80 nm (3). Macromolecule (b) was used for surficial functionalization of gold nanoparticles (1–3) to prepare nanoconjugates (1–3b). Antioxidant, antimicrobial, antibacterial, antibiofilm, antidiabetic, and deoxyribonucleic acid (DNA) cleavage activities of biocandidates (b, 1–3, and 1–3b) were examined to determine the optimum size of gold nanoparticles and the effect of modifying groups on their bioactivity in this study for the first time. The highest antioxidant activities were obtained for biocandidates (b and 1b) at 100 mg/L. The best minimum inhibitory concentration (MIC) values were obtained at 32 mg/L for bioagents (b, 1, and 3b) against E. faecalis whereas the MIC value was obtained at 32 mg/L for 1b against E. hirae and E. faecalis. Bioagents (b and 1–3b) exhibited high APDT activities (16 mg/L) against the studied microorganisms. The highest biofilm inhibition activities were obtained 94.57 and 89.28% for 50 mg/L nanoconjugate (1b) against S. aureus and P. aeruginosa, respectively. All the studied biocandidates inhibited 100% E. coli viability at 50 mg/L. The antidiabetic activities of biocandidates (b, 1–3, and 1–3b) were obtained between 7.52 and 100 mg/L. Bioagents (2, 3, 1b, and 2b) destroyed the DNA integrity, as well. The significant improvement in the biological activities of gold nanoparticles confirmed that new nanoconjugates especially 1b can be considered promising medical nanomaterials after further clinical investigation.