Jinling Huang

Enhanced Photodynamic Efficacy of Zinc Phthalocyanine by Conjugating to Heptalysine

Zinc phthalocyanine (ZnPc) is a promising photosensitizer for photodynamic therapy, but faces some challenges: ZnPc is insoluble in water and thus requires either special formulation of ZnPc by, e.g., liposome or Cremophor EL, or chemical modification of Pc ring to enhance its bioavailability and photodynamic efficacy. Here, we conjugated monosubstituted ZnPc-COOH with a series of oligolysine moieties with different numbers of lysine residues (ZnPc-(Lys)(n) (n = 1, 3, 5, 7, 9) to improve the water solubility of the ZnPc conjugates. We measured the photosensitizing efficacies and the cellular uptakes of this series of conjugates on a normal and a cancerous cell line. In addition, we developed a sensitive in situ method to distinguish the difference in photodynamic efficacy among conjugates. Our results showed that ZnPc-(Lys)(7) has the highest photodynamic efficacy compared to the other conjugates investigated.

Substituted zinc phthalocyanine as an antimicrobial photosensitizer for periodontitis treatment

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.

Synthesis, spectral and electrochemical characterization of non-aggregating α-substituted vanadium(IV)-oxo phthalocyanines

Two α-substituted vanadium-oxo phthalocyanines, [(OC6H3(t-Bu)2)4Pc]VO and [(OC8H17)4Pc]VO, where OC6H3(t-Bu)2 is 2,4-di-tert-butylphenoxy and OC8H17 is 2,2,4-tri-methyl-3-pentoxy, were synthesized and characterized by elemental analysis, mass spectrometry, UV-visible, IR, ESR spectroscopy and electrochemistry. Both complexes have good solubility and do not aggregate in polar or non-polar solvents. Three reductions and two oxidations can be observed in DMF containing 0.2 M TBAP. A HOMO-LUMO gap of ~1.4 V is seen for both complexes. The first two one-electron reductions and first oxidation are reversible diffusion controlled electrode processes under the given experimental conditions. The effects of solvent and phthalocyanine macrocycle substituents on the Q bands of the electronic absorption spectra are discussed.

Electrochemistry and spectroelectrochemistry of tetra-α-substituted metallophthalocyanines

Four tetra-α-substituted phthalocyanines, represented as [(OR)4Pc]M where OR is 2,2,4-tri-methyl-3-pentoxy and M = Co(II), Ni(II), Cu(II) or Zn(II), were investigated as to their electrochemistry, UV-visible and ESR spectroscopy. The electron-donating groups on the four α-positions of the phthalocyanine macrocycles lead to a 40 nm red-shift in the position of the most intense band in the UV-visible spectrum as compared to the unsubstituted (Pc)M derivative with the same central metal ion under the same solution conditions. The cobalt, nickel and copper complexes of [(OR)4Pc]M are soluble in nonaqueous media and show no evidence for aggregation at the millimolar concentration levels needed for electrochemical measurements. The Zn(II) complex aggregates in DMF at these concentrations but monomers are formed upon diluting the solution or by adding a complexing axial ligand such as pyridine. The first reduction and first oxidation of [(OR)4Pc]Co(II) leads to formation of a Co(I) and Co(III) phthalocyanine and this contrasts with the first reduction and first oxidation of the Ni(II), Cu(II) and Zn(II) derivatives where electron addition and electron abstraction occur at the conjugated macrocycle, leading to π-anion and π-cation radicals, respectively.

Isomeric separation and identification of tetra-, tri-, and di-β-sulphonic phthalocyanine zinc complexes

The synthesis, isomeric separation, and identification of β-sulphonic phthalocyanine zinc complexes were reported. While the sulphonic phthalocyanines have been studied extensively, the development of separation technology may enable deeper insights into their isomeric constitution. An ion-pair reversed-phase high performance liquid chromatography (IP-RP-HPLC) method was developed to separate the sulphonic phthalocyanine isomers. The results showed that the product of the condensation reaction is a mixture of all possible isomers with statistical distribution. Several isomers were obtained and structural determination was undertaken by NMR. Based on the IP-RP-HPLC elution sequence of these well-identified isomers, a relationship between the structure and efficiency was deduced: closely spaced intervals of sulphonic groups lead to higher hydrophobicity and shorter retention times on HPLC. Based on this relationship, each HPLC peak was assigned to the corresponding isomeric structure.

A convenient synthesis of a substituted phthalocyanine compound

A new substituted tetra-(4-octanethiol-5-nitro)phthalocyaninatocopper complex was synthesized by nucleophlic substitution of tetra-(4-bromo-5-nitro)phthalocyaninatocopper where the bromo activated by an ortho-nitro group is easily substituted by 1-octanethiol.

2-Benzyl­isoindoline-1,3-dione: a monoclinic polymorph

In the molecule of the title compound, C(15)H(11)NO(2), the dihedral angle between the ring systems is 81.3 (2)°. In the crystal structure, mol-ecules are held together via C-H⋯O inter-actions.

Synthesis, characterization and properties of some metallophthalocyanine complexes substituted by N -piperidineethanol

The preparation of eight metallophthalocyanine complexes substituted by N-piperidineethanol was achieved by tetramerization of 3-[2-(piperidin-1-yl)ethoxyl] phthalonitrile and 4-[2-(piperidin-1-yl)ethoxyl]phthalonitrile in the presence of a metal salt with n-pentanol as solvent and DBU as catalyst, respectively. These complexes were characterized by IR, elemental analysis, 1H NMR and mass spectra. Some properties such as UV/visible absorption spectra, rate of singlet oxygen yields, fluorescence spectra and quantum yields were examined and discussed.

Applications of Peptide Conjugated Photosensitizers in Photodynamic Therapy*: Applications of Peptide Conjugated Photosensitizers in Photodynamic Therapy*

Photodynamic therapy (PDT) relies on the interaction of light, photosensitizer, and the presence of oxygen, leading to cytotoxicity to the tissue containing the photosensitizer. The tissue specificity of photosensitizer is thus one of the key factors in photodynamic therapy. The limited targeting capability of current photosensitizers that are in the clinical applications has led to the active development of the new generation of photosensitizer. Another approach-peptide conjugation-to enhance the tissue specificity of photosensitizers were reviewed. The cell penetrating peptides, vasculature targeting peptides, and peptides targeting cell surface receptors were reviewed. The current research indicates that the effectiveness of peptide conjugation to confer the tissue specificity to photosensitizers.

Synthesis and photophysical properties of zinc phthalocyanines substituted with quinolinoxy group

The synthesis of tetrasubstituted zinc phthalocyanines bearing quinolinoxy groups are reported for the first time. The new compounds have been characterized by elemental analysis, IR, MS and electronic spectroscopy. The photophysical properties, such as the electronic absorption spectra and fluorescence spectra, have also been investigated and discussed together with the influence of substituent position and organic solvents on these properties. The introduction of quinolinoxy group to the Pc ring was found to affect these photophysical properties to some extent.