Institute of Fundamental Technological Research

The synthesis, photophysicochemical and photodynamic therapy (PDT) activities of benzothiazole substituted zinc phthalocyanine (Pc): 1 (asymmetrically substituted and composed of no charges), 2 (asymmetrically substituted and composed of three positive charges), and 3 (symmetrically substituted and composed of four positive charges), are presented. The triplet and singlet oxygen quantum yields were highest for complex 2 showing the importance of asymmetry and charge. The complexes are covalently and non-covalently linked to B doped detonation nanodiamonds (B@DNDs) to yield nanohybrids (B@DNDs-1, B@DNDs-2, B@DNDs-3). The presence of B@DNDs, asymmetry and positive charge resulted in improved PDT with the lowest cell viability being observed for B@DNDs-2 at 5%. The cell viability ranged from 5% to 7% for the nanohybrids compared to 19–26% for Pcs alone.

An amide mono substituted benzothiozole phthalocyanine: zinc(II) 3-(4-((3,17,23-tris(4-(benzo [d]thiazol-2-yl)
phenoxy)-9-yl)oxy) phenyl)amide phthalocyanine (NH2BzPc) was covalently linked to undoped and heteroatom
doped detonation nanodiamonds (DNDs): B@DNDs, P@DNDs, S@DNDs, N@DNDs, and S&N@DNDs There is a
drastic decrease in highest occupied molecular orbital (HOMO) – lowest unoccupied molecular orbital (LUMO)
energy gaps for nanoconjugates compared to DNDs alone. B@DNDs-NH2BzPc, S&N@DNDs-NH2BzPc, and
P@DNDs-NH2BzPc showed superior photodynamic therapy (PDT) effects. DNDs-NH2BzPc also had a small
HOMO-LUMO gap, but did not show improved PDT activity compared to the Pc alone, suggesting doping of
DNDs is important. This study shows improved PDT effect on Michigan Cancer Foundation-7 breast cancer lines
at 7.63%, 7.62% and 6.5% cell viability for P@DNDs-NH2BzPc, S&N@DNDs-NH2BzPc and B@DNDs-NH2BzPc,
respectively

The synthesis, photophysicochemical and photodynamic therapy (PDT) activity of quaternary benzothiazole substituted zinc phthalocyanine (2, containing two charges, and 3, containing four charges) are reported in this work. Furthermore, the activity of the synthesized complex was compared to non-quaternary derivative (1). Higher triplet and singlet oxygen quantum yields of 0.92 and 0.85, respectively, for quaternized complexes 2 and 3 compared to complex 1 alone. Complexes 1, 2 and 3 showed relatively no dark toxicity against the epithelial breast cancer cells with cell survival of above 90 ± 3%. The quaternary derivatives (2 and 3) showed superior PDT activity with 30% or less of viable cells at concentration of 50.0 μg/mL in comparison to complex 1 alone which further lay credence to the importance of quaternization in the enhancement of PDT activit