Metal chelates of porphyrin derivatives as sensitizers in photooxidation processes of sulfur compounds and in photodynamic therapy of cancer

Simple low cost porphyrinic photosensitizers for large scale chemoselective oxidation of sulfides to sulfoxides under green conditions: targeted protonation of porphyrins

Large scale chemoselective photooxidation of sulfides to sulfoxides in the presence of the diacids ofmeso-tetra(phenyl)porphyrin with different acids is reported.

Nanoscale theranostics for physical stimulus-responsive cancer therapies

Physical stimulus-responsive therapies often employing multifunctional theranostic agents responsive to external physical stimuli such as light, magnetic field, ultra-sound, radiofrequency, X-ray, etc., have been widely explored as novel cancer therapy strategies, showing encouraging results in many pre-clinical animal experiments. Unlike conventional cancer chemotherapy which often accompanies with severe toxic side effects, physical stimulus-responsive agents usually are non-toxic by themselves and would destruct cancer cells only under specific external stimuli, and thus could offer greatly reduced toxicity and enhanced treatment specificity. In addition, physical stimulus-responsive therapies can also be combined with other traditional therapeutics to achieve synergistic anti-tumor effects via a variety of mechanisms. In this review, we will summarize the latest progress in the development of physical stimulus-responsive therapies, and discuss the important roles of nanoscale theranostic agents involved in those non-conventional therapeutic strategies.

Selective aggregation of zinc phthalocyanines in the skin

In photodynamic therapy it is important to avoid undesirable side effects caused by photodynamic reactions with accumulated photosensitizers, especially in the skin. Although phthalocyanine monomers can serve as photosensitizers, aggregated phthalocyanines are inactive. In this study the aggregations of five zinc phthalocyanines (MSPc, TSPc, TX-101A, TX-105A and TX-106A) in the skin and in the tumor are compared. Every phthalocyanine was more dissociated in the tumor than in the skin. In particular, TX-101A and TX-106A remained in monomeric form in the tumor but were aggregated in the skin. The aggregation effects of phthalocyanines in organic solvents and biological materials were also investigated. These phthalocyanines were aggregated in water and ethanol and also by the addition of bovine serum albumin and ghosts of red cells. On the other hand, they were dissociated in propanol and also by the addition of low-density lipoprotein. It was found that the dissociation of these phthalocyanines depended strongly on the polarity of the solvents and on the biological microenvironment.

Photochemical Properties of Water-soluble Fluorinated Zinc Phthalocyanines and their Photocytotoxicity Against HeLa Cells

Three types of amphiphilic water-soluble fluorinated zinc phthalocyanines are characterized. They have absorption bands at long wavelength, which cause greater penetration depth of a tissue. The uptake and photodynamic activity of the phthalocyanines against HeLa cells were measured, showing that the phthalocyanines exhibited higher photodynamic activities than zinc tetrasulfonated phthalocyanine.

Synthesis of a Monofunctional Phthalocyanine on Silica

Silica of different surface area and grain size modified by aminopropyl groups reacted with 4-(3,4-dicyanophenoxy)benzoic acid chloride. The reaction of these benzamidophenoxydicarbonitrile modified silica gels with 4-(4-tert-butyl-phenoxy)-1,2-benzenedicarbonitrile in the presence of a zinc(II) salt results in covalently bonded phthalocyanine zinc(II) complexes with a loading between 1.8 × 10−5 and 1.7 × 10−6 mol g −1 silica. UV/vis reflectance spectra show that the phthalocyanines on the surface exist in a monomeric state. Cleavage at the amide bond between the silica and the phthalocyanine led to the corresponding monocarboxylic acid phthalocyanine derivative.

DNA-binding and oxidative properties of cationic phthalocyanines and their dimeric complexes with anionic phthalocyanines covalently linked to oligonucleotides

Design of chemically modified oligonucleotides for regulation of gene expression has attracted considerable attention over the past decades. One actively pursued approach involves antisense or antigene oligonucleotide constructs carrying reactive groups, many of these based on transition metal complexes. The complexes of Fe(II) and Co(II) with phthalocyanines are extremely good catalysts of oxidation of organic compounds with molecular oxygen and hydrogen peroxide. The binding of positively charged Fe(II) and Co(II) phthalocyanines with single- and double-stranded DNA was investigated. It was shown that these phthalocyanines interact with nucleic acids through an outside binding mode. The site-directed modification of single-stranded DNA by O2 and H2O2 in the presence of dimeric complexes of negatively and positively charged Fe(II) and Co(II) phthalocyanines was investigated. These complexes were formed directly on single-stranded DNA through interaction between negatively charged phthalocyanine in conjugate and positively charged phthalocyanine in solution. The resulting oppositely charged phthalocyanine complexes showed significant increase of catalytic activity compared with monomeric forms of phthalocyanines Fe(II) and Co(II). These complexes catalyzed the DNA oxidation with high efficacy and led to direct DNA strand cleavage. It was determined that oxidation of DNA by molecular oxygen catalyzed by complex of Fe(II)-phthalocyanines proceeds with higher rate than in the case of Co(II)-phthalocyanines but the latter led to a greater extent of target DNA modification.

Preparation of a water-soluble fluorinated zinc phthalocyanine and its effect for photodynamic therapy

An amphiphilic fluorinated phthalocyanine, zinc tetracarboxyoctafluorophthalocyanine (ZnC4F8Pc) was synthesized and characterized. Its photodynamic efficiency for HeLa cells was compared with hydrophilic zinc octacarboxyphthalocyanine (ZnC8Pc) and hydrophobic zinc hexadecafluorophthalocyanine (ZnF16Pc). ZnC4F8Pc had a remarkable photodynamic effect among the phthalocyanines used. The effect is apparently caused by the fact that ZnC4F8Pc is mainly accumulated in the hydrophobic lipid membrane and is in the photoactive monomer form in HeLa cells.