DNA Targeting Long-Chain Alkoxy Appended Tin(IV) Porphyrin Scaffolds: Photophysical and Antimicrobial PDT Investigations

Abstract

Tin(IV) porphyrin scaffolds having long-chain (C 8 and C 16 ) alkoxyphenyl group at one meso position were synthesized with axial dichloro and dihydroxo ligands. Modifications with respect to the alkoxy chain length and the axial ligands were investigated using UV−vis and fluorescence spectroscopy as well as cyclic voltammetry. Significantly higher molar absorption coefficients were noted with dichloro axial ligands whereas higher fluorescence quantum yields were observed for C 8 alkoxy chain substituents. Electrochemical redox data revealed that the porphyrin ring became difficult to reduce consequent to the presence of electron donating alkoxy chain. Evaluation of the aggregation behavior in different organic solvents and DMF-water mixture has been carried out. The singlet oxygen production and photostability data are supportive of their suitability for antibacterial photodynamic therapy. The antibacterial studies carried out in Gram negative (E. coli) and Gram positive (B. subtilis) bacteria using agar well diffusion and LB broth assay revealed selective toxicity in B. Subtilis cells. Fluorescence microscopy and competitive DNA binding studies with Hoechst 33342 revealed DNA binding at the minor groove which was further substantiated with molecular docking studies.

Novel Type of Water-Soluble Photosensitizer from Trichoderma reesei for Photodynamic Inactivation of Gram-Positive Bacteria

“…In addition, new efficient antibacterial therapies have been also applied in treating bacterial infections, such as photodynamic therapy (PDT) (11,12) and photothermal therapy (PTT) (13,14). Antimicrobial photodynamic therapy (APDT) has been widely reported as a promising alternative to traditional antibiotics in the past few years (15,16). APDT generally involves molecular oxygen, light source, and photosensitizer (PS).…”

Photodynamic activity of Sn(IV) meso-tetraacenaphthylporphyrin and its methyl-β-cyclodextrin inclusion complexes on MCF-7 breast cancer cells

“…Upon inserting the Sn(IV) ion, the peak for the two inner N-H protons at −2.30 ppm was no longer observed, confirming the successful metallation of the porphyrin. It proved impossible to identify the hydroxyl proton peak in a similar manner to what has been reported previously in other recent studies with Sn(IV) tetraarylporphyrin complexes [38][39][40][41][42].…”

Mitochondrial‐DNA‐Targeted IrIII‐Containing Metallohelices with Tunable Photodynamic Therapy Efficacy in Cancer Cells

“…Molecular docking studies using B‐DNA dodecamer were further explored to gain insight into the preferred docked position and orientation of the Ir III ‐containing metallohelices interacting with DNA (Supporting Information, Section S12) . As evident from Figure a–c, H2 b , M3 b , and H4 b bound at the major groove of DNA, with average binding energies of −5.73, −6.35, and −6.25 kcal mol −1 , respectively.…”

“…[4] Furthermore,since DNAencodes and regulates most aspects of life and represents one of the main targets of many anticancer drugs,t he development of DNA-targeted PDT agents that result in enhanced PDT efficiencyi sa lso highly desirable. [5] Although an umber of PDT agents,i ncluding organic dyes, [6] polymers, [7] metallo-supramolecules, [8] and inorganic nanoparticles, [9] have been designed for targeted PDT,t he typical method for designing targeted PDT agents requires covalent conjugation of atargeting domain (namely, as mall molecule,p eptide,o ra ntibody) to the skeletons. [6a] This approach always results in complicated and inefficient organic synthesis.T he cumbersome and costly procedures prevent their further practical applications.…”