pH Dependence of fluorescence and absorbance spectra of free sulphonated aluminium phthalocyanine and its conjugate with monoclonal antibodies

Savitsky, Alexander P.; Lopatin, K. V.; Golubeva, N. A.; Poroshina, Marina Yu.; Chernyaeva, Elena B.; Stepanova, N. V.; Solovieva, L. I.; Luk’yanets, E. A.

doi:10.1016/1011-1344(92)85073-4

Cited by 19 publications

(9 citation statements)

References 6 publications

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“…TOF-SIMS analysis of deposited films (39) indicates Cl Ϫ as an axial ligand for aluminum phthalocyanine (chloro-AlPc) in low pH solutions. This is consistent with the scheme proposed by Savitsky et al (8); and with our observation that, whilst at a pH value of 2.5 AlPcS 2 is precipitated from PBS using AgNO 3 solution, at pH values between 3.5 and 7.5 precipitation is minimal. These results lead to the conclusion that Cl Ϫ ceases to be an axial ligand upon increasing the pH from 2.5 to 3.5.…”

Section: The Effect Of Ph On the Absorption Spectrumsupporting

confidence: 94%

“…It has been proposed by Ferraudi et al (6) (Scheme 1) that shifts in the wavelengths of the absorption maxima of the Q-band (the first two, typically degenerate, electronically excited states) and the Soret band (overlapping higher energy excited-states) of aqueous tetra-sulphonated aluminum phthalocyanine (AlPcS 4 ) are indicative of changes in the axial ligands. Savitsky et al (8) have estimated pK values for the pH-dependent ligand changes of aqueous AlPcS 2 using steady-state fluorescence measurements (Scheme 2). The pK for the protonation of the sulphonate groups is expected to be ϳ0.7, that of benzosulphonic acid (9).…”

Section: Introductionmentioning

confidence: 99%

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The Effect of pH on the Photophysics and Photochemistry of Di-sulphonated Aluminum Phthalocyanine

Ostler¹,

Scully²,

Taylor³

et al. 2007

Photochemistry and Photobiology

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The results of a study of the effect of pH on the photophysics and photochemistry of di‐sulphonated aluminum phthalocyanine (AlPcS2) in aqueous solution are presented. The pH dependence of the triplet quantum yield, fluorescence quantum yield, singlet‐oxygen quantum yield, triplet lifetime, fluorescence lifetime and apparent dimerization constants is investigated and the results interpreted in terms of the pH dependence of the nature of the axial ligands. Evidence that the aluminum–axial ligand bond strength, rather than dimer binding energy that determines the extent of dimerization is provided by semi‐empirical and ab initio calculations. Possible dimer structures obtained using ab initio calculations are discussed.

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Section: The Effect Of Ph On the Absorption Spectrumsupporting

confidence: 94%

Section: Introductionmentioning

confidence: 99%

The Effect of pH on the Photophysics and Photochemistry of Di-sulphonated Aluminum Phthalocyanine

Ostler¹,

Scully²,

Taylor³

et al. 2007

Photochemistry and Photobiology

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“…Savitsky et al [13] found similar shifts in the maximum excitation and emission wavelength for A1PcS (a mixture of several degrees of sulfonation), which are consistent with the existence of two acid-base equilibria. They assigned these shifts to equilibria with stepwise deprotonation of axially coordinated water:…”

Section: Solvent Phsupporting

confidence: 62%

<title>Liquid chromatography combined with visible diode-laser-induced fluorescence detection for photosensitizers</title>

et al. 1994

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A combination of conventional-size liquid chromatography and visible diode-laser induced fluorescence (DIO-L]F) detection has been developed and applied for the detection of a model photosensitizer, AJPcS2, in biological samples. Conventional fluorimetry was found to give unsatisfactory information. A detection limit of 2.1x1012 M (SIN = 3) was obtained for A1PcS2 in both rat urine and faeces exiracts using the DIO-LIF system, 20-fold lower than obtained with a conventional fluorescence detection system, when used in combination with chromatography. . INTRODUCTIONPhotodynamic therapy (PDT) is a treatment for neoplastic diseases based on selective cell injury. A photosensitizer is administered and after a certain period of time the tumor tissue is irradiated, what results in tumor necrosis [1]• Tumor destruction is thought to be based on the photochemical formation of cytotoxic oxygen species as a result of energy transfer from excited photosensitizers. Photosensitizers should show selective or prolonged retention in tumor tissue compared to nonnal tissue and afterwards be easily cleared from all tissues. Furthennore, they should have appropriate photophysical characteristics, be chemically and photochemically stable and non-toxic in the absence of light [2]• Their absorption maximum should preferably be at a long wavelength, where tissue transparency is high.The most widely used photosensitizer for PDT is Hematoporphyrin Derivative (HpD), a complex mixture of structurally related dicarboxylic porphyrins. In PDT, HpD is activated at a wavelength of 630 nm because tissue penetration is too low at 400 run, the maximum absorption band of the porphyrins present in HpD. A more suitable photosensitizer would have a better defined composition and a maximum absorption wavelength longer than 650 nm [1] A number of new photosensitizers has been developed with this requirement in mind [31141• We have developed a separation and detection system for so-called second generation photosensitizers and applied it to a model compound: disulfonated aluminum phthalocyanme (AIPcS2). The absorption maximum of this phthalocyanine is at a wavelength of 674 nm in methanol (E = 180,000 cm M1).It is well known that the number of sulfonate groups on the phthalocyanine is a major factor in the uptake and the disthbution of a mixture of AIPcSn (n = 1-4 sulfonate groups) in tumor cells [5] [6J• AJPcS2 can be obtained as a preparative chromatographic fraction from such an AIPcSn mixture [7]• However, several A1PcS2 isomers are possible and the isomeric SO3H distribution in the AIPcS2 fraction depends on the method of synthesis applied for the AIPcSn mixture [8][9][lO]• It is N expected that AIPcS2 isomers with sulfonates on adjacent rings are more lipophiic than those with sulfonates on opposite rings [1O]• Figure 1: Structure of a A1PcS2-isomer O-8194-1351-8/94/$6.OO SPIE Vol. 2084 1255 N Downloaded From: http://proceedings.spiedigitallibrary.org/ on 06/24/2016 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx

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“…For photodynamic therapy, one method of achieving this is to conjugate the photosensitizer to an antibody raised against the target organism or cell. Photosensitizers that have been conjugated to antibodies include porphyrins (19), sulfonated aluminum phthalocyanine (20), and hematoporphyrin (10). The target cells have mainly been neoplasms; however, Berthiaume et al (1) have shown that an antibody against Pseudomonas aeruginosa (which they used to infect the dorsal skin of mice) conjugated with tin(IV) chlorin e 6 achieved a 95% reduction in viable bacteria when exposed to light with a wavelength of 630 nm.…”

mentioning

confidence: 99%

Antibody-Targeted Lethal Photosensitization ofPorphyromonas gingivalis

Bhatti

MacRobert

Henderson

et al. 2000

Antimicrob Agents Chemother

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We have previously demonstrated that Porphyromonas gingivalis is susceptible to killing by toluidine blue O (TBO) when irradiated with light from a helium-neon (HeNe) laser. The aim of this study was to determine whether a TBO-antibody conjugate (Ab-TBO) could be used to specifically target P. gingivalis to lethal photosensitization in the presence of Streptococcus sanguis or human gingival fibroblasts (HGFs). When a mixture of P. gingivalis and S. sanguis was exposed to 4 g of TBO/ml and irradiated with HeNe laser light, there were 1.5-and 4.0-log 10 -unit reductions in the viable counts, respectively. In contrast, when TBO was conjugated with a murine monoclonal antibody against P. gingivalis lipopolysaccharide, the reductions in viable counts of P. gingivalis and S. sanguis amounted to 5.0 and 0.1 log 10 units, respectively. Lethal photosensitization of P. gingivalis in the presence of HGFs using unconjugated TBO resulted in a 0.7-log 10 -unit reduction in P. gingivalis viable counts and a 99% reduction in the incorporation of tritiated thymidine ([ 3 H]Tdr) by the HGFs. In contrast, when the Ab-TBO conjugate was used, there was a 100% reduction in P. gingivalis viable counts but no significant reduction in the incorporation of [ 3 H]Tdr by HGFs. These results demonstrate that specific targeting of P. gingivalis can be achieved using TBO conjugated to a monoclonal antibody raised against a cell surface component of this organism.

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pH Dependence of fluorescence and absorbance spectra of free sulphonated aluminium phthalocyanine and its conjugate with monoclonal antibodies

Cited by 19 publications

References 6 publications

The Effect of pH on the Photophysics and Photochemistry of Di-sulphonated Aluminum Phthalocyanine

The Effect of pH on the Photophysics and Photochemistry of Di-sulphonated Aluminum Phthalocyanine

<title>Liquid chromatography combined with visible diode-laser-induced fluorescence detection for photosensitizers</title>

Antibody-Targeted Lethal Photosensitization ofPorphyromonas gingivalis

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