Journal of Porphyrins and Phthalocyanines

A simple novel near-infrared water-soluble glucose-conjugated porphyrin, 5,15-bis-[(trimethylsilyl)ethynyl]-10,20-bis[4-β-D-glucopyranosyl)phenyl]porphyrin, with good optical stability and high emission ability in near-infrared region, was synthesized. And Optical Imaging in vivo with this compound as probe was performed on liver tumor-bearing nude mice. The result shows that this glucose-conjugated porphyrin could display information in vivo more than 1 cm in depth, which implies its potential application as optical probe in cancer diagnosis.

Interaction between bovine serum albumin (BSA) and tetraantraquinoporphyrazines (TAP) and tetrasulphophthalocyanine (Pc) aluminum hydroxide was studied by means of electron absorption spectroscopy, IR spectroscopy, fluorescence spectroscopy and differential scanning calorimetry. It was found that the complex formation of BSA with the TAPs results in increase of thermal stability of the protein while Pc does not have remarkable influence on the protein thermal denaturation.

A series of new spin-labeled porphyrin containing isoindoline nitroxide moieties were synthesized and characterized as potential free radical fluorescence sensors. Fluorescence-suppression was observed in the free-base monoradical porphyrins, whilst the free-base biradical porphyrins exhibited highly suppressed fluorescence about three times greater than the monoradical porphyrins. The observed fluorescence-suppression was attributed to enhanced intersystem crossing resulting from electronexchange between the doublet nitroxide and the excited porphyrin fluorophore. Notably, fluorescencesuppression was not as strong in the related metalated porphyrins, possibly due to insufficient spin coupling between the nitroxide and the porphyrin. Continuous wave EPR spectroscopy of the diradical porphyrins in fluid solution suggests that the nitroxyl-nitroxyl interspin distance is long enough and tumbling is fast enough not to detect dipolar coupling.

The aggregation of 85 porphyrin derivatives and a report on a kinetic and thermodynamic study of such aggregation behavior on varying the derivatives of porphyrin was carried out using molecular dynamics simulation and Docking. Distance diagrams of simulated compounds were obtained and decrease of curves is a clear evidence of the aggregation. Aggregation rates were studied by origin software. In order to calculate interaction energies of derivatives, compounds were docked and the equilibrium constant of porphyrin-porphyrin interaction were obtained. Quantitative Structure-Property Relationship (QSPR) studies were performed for the sets of 85 Porphyrin derivatives. Multiple Linear Regression method (MLR) and Principal Component Analysis (PCA) were used and resulted in useful models with good prediction ability. This models were able to predict the kinetic and equilibrium constant for all sets of our compounds. The correlation coefficients for prediction of rate and logarithm of equilibrium constants were 0.67 and 0.97 by MLR method respectively and 0.90 for prediction of equilibrium constant by PCA analyses. In order to have a better prediction, compounds were divided into two groups, oxygenated and non-oxygenated group and correlation coefficient for prediction of rate constants of them were obtained 0.89 and 0.94 by MLR model respectively. Results of structure-property relationship showed that, larger, more hydrophobe and more planner derivatives have higher aggregation rate.

The complexation of single walled carbon nanotubes (SWNTs) with neutral, anionic and cationic porphyrins has been investigated under identical complex forming conditions. The determination of the porphyrin loading reveals large differences depending on the nature of the porphyrin used. Combinations of different porphyrins to form mixed hetero-porphyrin complexes shows that the mixture of a cationic and anionic porphyrin results in loading which is an order of magnitude larger than in all other complexes. This complex also exhibits high adsorption and emission intensities and can be regarded as an extended co-operative binary ionic (CBI) solid. The complexes were further studied using Raman spectroscopy, elemental analysis, AFM and cyclic voltammetry.

A series of new purpurinimide-hydrazone conjugates were synthesized, and their in vitro anticancer efficacy against A549 lung cancer cell lines was evaluated. It was found that the incorporation of the hydrazone group to the purpurinimide could increase their anticancer activities via a combination of photodynamic therapy and chemotherapy.

^99mTc(CO)₃-TPPS₄ was prepared via the precursor [^99mTc(CO)₃(H₂O)₃]⁺ and a preliminary investigation on its stability and behavior in Hep2 tumor cells and hepatoma-bearing mice were conducted. Labeling yield and stability of ^99mTc(CO)₃-TPPS₄ was radioactively analyzed by paper chromatography. Hep2 tumor cells were incubated with ^99mTc(CO)₃-TPPS₄ complex system in the substrate and isolated from the substrate for radioactivity count. Then ^99mTc(CO)₃-TPPS₄ complex system was intravenously injected in hepatoma-bearing mice and directly injected in tumor tissue of the mice. Mice were photographed using SPECT. Labeling yields of ^99mTc(CO)₃-TPPS₄ were more than 90% at pH = 7–8, 30 min, in a boiling bath, and it was stable for at least 14 h at pH = 2–8, rt ~95 °C. The uptake of ^99mTc(CO)₃-TPPS₄ in HepG2 tumor cells was only 3–4% with the maximum uptake-time of 20 min. The SPECT images of hepatoma-bearing nude mice showed no uptake or little retention of ^99mTc(CO)₃-TPPS₄ in the tumor tissue. Then the differences between ^99mTc(CO)₃-TPPS₄ and TPPS₄ were analyzed by fluoroscopy and molecular structure. It was found that the paper chromatography, HepG2 tumor cell uptake and the optimized porphyrin ring conformation of ^99mTc(CO)₃-TPPS₄ were quite different from those of TPPS₄. It was indicated that ^99mTc(CO)₃-TPPS₄ had no uptake or little retention in hepatic tumors, unlike those biological behaviors of TPPS₄. This may be due to the modification of porphyrin ring conformation of TPPS₄ by ^99mTc(CO)₃ core.

The QCA paradigm is one of the approaches to decrease the size scale of computing devices. When molecules are used as QCA cells, they may be able to perform computing at room temperature. This paper describes a novel molecular QCA cell candidate which is a side-by-side iron phthalocyanine dimer, and an investigation of its optical and redox properties. The new dodeca(pentyloxy) substituted side-by-side iron phthalocyanine dimer, along with the octa(pentyloxy) iron phthalocyanine monomer, are soluble in non-polar organic solvents. These compounds were isolated by gel permeation chromatography (GPC) and high-performance liquid chromatography (HPLC) to final purities of 98% and 99%, respectively. The NMR spectra of both compounds in CDCl₃ are broad due to aggregation, but become well resolved after the addition of the coordinating solvent pyridine-d₅. Addition of pyridine also gives changes in the UV-vis spectra and electrochemical peaks of both monomer and dimer in dichloromethane indicative of axial iron coordination. The electrochemical data indicates the loss of pyridine ligands from the oxidized products of both monomer and dimer. The comproportionation constant of side-by-side phthalocyanine dimer shows that its oxidized and reduced mixed-valence complexes are fairly stable. The dimer is thus a candidate for molecular QCA systems.

In the last decades the worldwide rise in antibiotic resistance has intensified the development of new antimicrobial agents. Photodynamic antimicrobial chemotherapy (PACT) has been used successfully to inactivate bacteria. We herein report a new zinc phthalocyanine based photosensitizer conjugated with polylysine moiety (ZnPc-PL). This photosensitizer significantly inactivated Porphyromonas gingivalis, the primary pathogenic bacteria responsible for periodontitis. No obvious phototoxicity was found to either mammalian bone marrow stromal cells (BMSC) or human periodontal ligament cells (HPDLC), indicating the high selectivity of ZnPc-PL toward bacteria. Furthermore, we established an experimental periodontitis model on beagle dogs to test the antimicrobial efficacy in vivo. The amount of gingival crevicular fluid (GCF) and the activity of crevicular fluid aspartate aminotransferase (AST) were monitored and were found to reduce significantly in the ZnPc-PL treated group compared to the controls (laser only and no treatment). In addition, PACT with ZnPc-PL caused a reduction in the bacterial burden by 100-fold compared to controls. Taken together, these findings suggest ZnPc-PL is a promising antimicrobial photosensitizer for the treatment of periodontal diseases.