Porphyrin Photosensitizers Research Articles

Effect of Pluronic F127 on the photosensitizing properties of dimegine in the presence of nanoparticles

It is shown that the activity of the water-soluble porphyrin photosensitizer dimegine (DMG) in the oxidation reaction of tryptophan, a test reaction for photodynamic therapy (PDT), can be enhanced by introducing silver, gold, and hydroxyapatite nanoparticles (NP) into the reaction medium if an amphiphilic polymer (AP) with the properties of a SAS is introduced into this mixture. It is concluded that the effect of enhancing the photosensitizing activity of dimegine is due to the formation of nanoparticle-Pluronic-porphyrin triple systems in which Pluronic (PL) plays the role of a bridge, forming complex and adsorption bonds with porphyrin and nanoparticles.

Chemical Synthesis and Medicinal Applications of Glycoporphyrins.

This review presents an in-depth overview of the modification of porphyrins with bioconjugates and their applications in medicine today. Porphyrin bioconjugates ranging from nucleotides to steroids are under active scrutiny. However, carbohydrates have been at the forefront of such research in recent years and offer significant potential. This is attributed to their own selectivity to lectins on the surface of cancer cells and their influence on the amphiphilicity of the porphyrin macrocycle. These characteristics and the tendency of porphyrin photosensitizers to accumulate in tumor tissues make glycoporphyrins promising candidates for use as photosensitizers. Thus, a detailed overview of the synthesis and biological evaluation of glycoporphyrins is given with a particular focus on their applications in photodynamic therapy and their future prospects as drug candidates have been reported.

Photochemical Property and Photodynamic Activity of Tetrakis(2-naphthyl) Porphyrin Phosphorus(V) Complex

Photochemical Property and Photodynamic Activity of Tetrakis(2-naphthyl) Porphyrin Phosphorus(V) Complex

Antiproliferative effects of ZnO, ZnO-MTCP, and ZnO-CuMTCP nanoparticles with safe intensity UV and X-ray irradiation.

In photodynamic therapy (PDT) of cancer both the light and the photosensitizing agent are normally harmless, but in combination they could result in selective tumor killing. Zinc oxide nanoparticles were synthesized and coated with the amino acid cysteine to provide an adequate arm for conjugation with porphyrin photosensitizers (meso-tetra (4-carboxyphenyl) porphyrin [MTCP] and CuMTCP). Porphyrin-conjugated nanoparticles were characterized by TEM, FTIR, and UV-vis, and fluorescence spectrophotometry. The 3-[4, 5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) assay was used to measure cell viability in the presence or absence of porphyrin conjugates following UV and X-ray irradiation. The uptake of the porphyrin-conjugated ZnO nanoparticles by cells was detected using fluorescence microscopy. Our results indicated that the survival of T-47D cells was significantly compromised in the presence of ZnO-MTCP-conjugated nanostructures with UV light exposure. Exhibition of cytotoxic activity of ZnO-MTCP for human prostate cancer (Du145) cells occurred at a higher concentration, indicating the more resistant nature of these tumor cells. ZnO-CuMTCP showed milder cytotoxic effects in human breast cancer (T-47D) and no cytotoxic effects in Du145 with UV light exposure, consistent with its lower cytotoxic potency as well as cellular uptake. Surprisingly, none of the ZnO-porphyrin conjugates exhibited cytotoxic effects with X-ray irradiation, whereas ZnO alone exerted cytotoxicity. Thus, ZnO and ZnO-porphyrin nanoparticles with UV or X-ray irradiation may provide a suitable treatment option for various cancers.

Acute Hepatic Porphyria.

The porphyrias comprise a set of diseases, each representing an individual defect in one of the eight enzymes mediating the pathway of heme synthesis. The diseases are genetically distinct but have in common the overproduction of heme precursors. In the case of the acute (neurologic) porphyrias, the cause of symptoms appears to be overproduction of a neurotoxic precursor. For the cutaneous porphyrias, it is photosensitizing porphyrins. Some types have both acute and cutaneous manifestations. The clinical presentation of acute porphyria consists of abdominal pain, nausea, and occasionally seizures. Only a small minority of those who carry a mutation for acute porphyria have pain attacks. The triggers for an acute attack encompass certain medications and severely decreased caloric intake. The propensity of females to acute attacks has been linked to internal changes in ovarian physiology. Symptoms are accompanied by large increases in delta-aminolevulinic acid and porphobilinogen in plasma and urine. Treatment of an acute attack centers initially on pain relief and elimination of inducing factors such as medications; glucose is administered to reverse the fasting state. The only specific treatment is administration of intravenous hemin. An important goal of treatment is preventing progression of the symptoms to a neurological crisis. Patients who progress despite hemin administration have undergone liver transplantation with complete resolution of symptoms. A current issue is the unavailability of a rapid test for urine porphobilinogen in the urgent-care setting.

Physicochemical properties of potential porphyrin photosensitizers for photodynamic therapy

This research evaluated the suitability of synthetic photosensitizers for their use as potential photosensitizers in photodynamic therapy using steady state and time-resolved spectroscopic techniques. Four tetraphenylporphyrin derivatives were studied in ethanol and dimethyl sulfoxide. The spectroscopic properties namely electronic absorption and emission spectra, ability to generate singlet oxygen, lifetimes of the triplet state, as well as their fluorescence quantum yield were determined. Also time-correlated single photon counting method was used to precisely determine fluorescence lifetimes for all four compounds. Tested compounds exhibit high generation of singlet oxygen, low generation of fluorescence and they are chemical stable during irradiation. The studies show that the tested porphyrins satisfy the conditions of a potential drug in terms of physicochemical properties.

The influence of temperature on the photo-oxidation rate of tryptophan in the presence of complexes of porphyrins with amphiphilic polymers**This work was supported by the Russian Foundation for Basic Research (project nos. 13-02-12422ofim and 13-02-00934).

The influence of temperature on the photocatalytic activity of the complexes of water-soluble porphyrin photosensitizers with amphiphilic polymers, such as poly-4-vinylpyrrolidone, polyethylene oxide, and Pluronic F127 (triblock copolymers of ethylene oxide and propylene oxide) in photo-oxidation reaction of tryptophan in the aqueous solution has been investigated. It has been shown that in the temperature range of 10–40 °C the addition of these polymers increases the activity of triglucamine salt of chlorine e6, tertrasodium salt of tetrasulfophenilporfirina and dimegin. The greatest influence on the rate of photo-oxidation appears to be rendered by the introduction of poly-4-vinylpyrrolidone in the presence of which the value of the rate constant increased by 30–70%. The strongest effect of the polymers is observed at 20–23 °C for dimegin, triglucamine salt of chlorine e6, and for tertrasodium salt of tetrasulfophenilporfirina at 30 °C. We suggest that the effect of the polymer on the effective rate constant relates to the restructuring of the supramolecular structure of polymers during temperature changes.

Study on nanocomposite construction based on the multi-functional biotemplate self-assembled by the recombinant TMGMV coat protein for potential biomedical applications.

Nowadays there is a growing interest in bio-scaffolded nanoarchitectures. Rapid progress in nanobiotechnology and molecular biology has allowed the engineering of inorganic-binding peptides termed as genetically engineered polypeptides for inorganics (GEPIs) into self-assembling biological structures to facilitate the design of novel biomedical or bioimaging devices. Here we introduce a novel nanocomposite comprising a self-assembled protein scaffold based on a recombinant tobacco mild green mosaic tobamovirus (TMGMV) coat protein (CP) and the photocatalytic TiO2 nanoparticles attached to it, which may provide a generic method for materials engineering. A template containing a modified TMGMV CP (mCP) gene, with the first six C-terminal amino acid residues deleted to accommodate more foreign peptides and expressing a site-directed mutation of A123C for bioconjugation utility, and two genetically engineered mutants, Escherichia coli-based P-mCP-Ti7 containing a C-terminal TiO2 GEPI sequence of seven peptides (Ti7) and Hi5 insect cells-derived E-CP-Ti7-His6 C-terminally fused with Ti7+His6 tag were created. Expression vectors and protocols for enriching of the two CP variants were established and the resultant proteins were identified by western blot analysis. Their RNA-free self-assembling structures were analyzed by transmission electron microscopy (TEM) and immuno-gold labeling TEM analysis. Adherence of nanoparticles to the P-mCP-Ti7 induced protein scaffold was visualized by TEM analysis. Also discussed is the Cysteine thiol reactivity in bioconjugation reactions with the maleimide-functionalized porphyrin photosensitizers which can function as clinical photodynamic therapy agents. This study introduced a novel approach to producing an assembly-competent recombinant TMGMV CP, examined its ability to serve as a novel platform for the multivalent display of surface ligands and demonstrated an alternative method for nanodevice synthesis for nanobiotechnological applications by combining GEPIs-mediated immobilization with the controllability of self-assembling recombinant TMGMV CP.

Binding Studies of Small Molecules to Telomeric Quadruplex DNA for Targeted Singlet Oxygen Production

Recent studies [Shieh et al., ACSNano (2010), 4, 1433; Yin et al., Chem. Comm (2012), 48, 6556] have suggested that G-quadruplexed DNA (qDNA) structures can serve as carriers for targeted delivery of photosensitizers in photodynamic therapies. In our studies, we have investigated the in vitro singlet oxygen production from the photosensitive porphyrins, N-methyl mesoporphyrin IX (NMM) and 5,10,15,20-tetrakis(N-methyl-4-pyridyl)-21H,23H-porphine tetratosylate (TMPyP4), when bound to both calf thymus duplex DNA (ct-DNA) and K+-stabilized G-quadruplexed human (hTTAGGG)4 telomeric DNA (qDNA). Competition micro-dialysis assays confirmed selective binding of NMM to the mixed hybrid qDNA conformation over TMPyP4, which binds non-selectively to both qDNA and ct-DNA. Sensitized singlet oxygen production was detected using the fluorescent singlet oxygen sensor green (SOSG) assay immediately following porphyrin-DNA irradiation. First-order singlet oxygen generation was detected for both NMM and TMPyP4 when bound to qDNA. However, no appreciable singlet oxygen production was detected for NMM when bound to ct-DNA suggesting potential targeted chemotherapeutic applications for NMM bound to qDNA. CD-studies suggest no change in conformation of the qDNA following irradiation. Currently, we are investigating the effect of the Na+-stabilized antiparallel qDNA conformation on rate and efficiency of singlet oxygen production from these porphyrins. (Supported by NIH-SCORE GM 095437-04.)

Photodynamic therapy of oligoethylene glycol dendronized reduction-sensitive porphyrins.

OEGylation of porphyrins via a disulfide linkage to form a novel class of dendritic porphyrin photosensitizers (PSs) is presented. These amphiphilic PSs possess precise molecular structures which could self-assemble into spherical aggregates in aqueous solutions. Their thermoresponsiveness was investigated using UV-Vis spectroscopy, and their reduction responsive properties were inspected using dynamic light scattering and TEM measurements. Moreover, the uptake of porphyrin-containing dendritic micelles by cells and release of reduction-sensitive PSs were investigated using flow cytometry and confocal laser scanning microscopy. The results showed that the cellular uptake of dendritic micelles was more than that of free porphyrin and the uptake process was time-dependent. Additionally, the phototoxicity of these dendritic PS micelles was investigated by MTT assay. It was found that dendritic micelles exhibited efficient phototoxicity to cancer cells while the free porphyrin had nearly no toxicity under light irradiation. All results indicate that these dendritic PSs are promising for photodynamic therapy.

Photocontrollable release and enhancement of photodynamic therapy based on host-guest supramolecular amphiphiles.

A light-controlled porphyrinic photosensitizer release system was developed based on host-guest TPP-Azo/PEG-β-CD supramolecular amphiphiles, which could significantly enhance the efficiency of photodynamic therapy. TPP-Azo was prepared via esterification between TPP and Azo derivatives, and further used to construct supramolecular amphiphiles with PEG-β-CD. TEM images showed that TPP-Azo/PEG-β-CD amphiphiles can self-assemble into spherical micelles, and then disaggregate under irradiation with 365 nm UV light. The phototoxicity and bio-distribution of TPP-Azo/PEG-β-CD micelles against the MCF-7 cell line were also evaluated by MTT assay, flow cytometry and confocal scanning laser microscopy, respectively. According to MTT assay, the IC50 of the spherical micelle was 31.2 μg mL-1, but it became 20.6 μg mL-1 upon pre-irradiation with 365 nm UV light. This shows for the first time that UV light can well stimulate the release of porphyrin photosensitizers and improve the photodynamic therapy efficiency based on the system of host-guest supramolecular amphiphiles.

A polydiacetylene–nested porphyrin conjugate for dye-sensitized solar cells

A novel polydiacetylene–nested porphyrin photosensitizer was prepared and explored for its potential in dye-sensitized solar cells.

Evaluation of the interplay among the charge of porphyrinic photosensitizers, lipid oxidation and photoinactivation efficiency in Escherichia coli

Photodynamic inactivation (PDI) is a simple and controllable method to destroy microorganisms based on the production of reactive oxygen species (ROS) (e.g., free radicals and singlet oxygen), which irreversibly oxidize microorganism’s vital constituents resulting in lethal damage. This process requires the combined action of oxygen, light and a photosensitizer (PS), which absorbs and uses the energy from light to produce ROS. For a better understanding of the photoinactivation process, the knowledge on how some molecular targets are affected by PDI assumes great importance. The aim of this work was to study the relation between the number and position of positive charges on porphyrinic macrocycles and the changes observed on bacterial lipids. For that, five porphyrin derivatives, bearing one to four positive charges, already evaluated as PS on Escherichia coli inactivation, have been tested on lipid extracts from this bacterium, and also on a simple liposome model. The effects were evaluated by the quantification of lipid hydroperoxides and by analysis of the variation of fatty acyl profiles. E. coli suspensions and liposomes were irradiated with white light in the presence of each PS (5.0μM). Afterwards, total E. coli lipids were extracted and quantified by phosphorus assay. Lipid oxidation on bacteria and on liposomes was quantified by ferrous oxidation in xylenol orange (FOX2 assay) and the analysis of the fatty acid profile was done by gas chromatography (GC). As previously observed for E. coli viability, an overall increase in the lipid hydroperoxides content, depending on the PS charge and on its distribution on the macrocycle, was observed. Analysis of the fatty acid profile has shown a decrease of the unsaturated fatty acids, corroborating the relation between lipid oxidation and PDI efficiency. Bacterial membrane phospholipids are important molecular targets of photoinactivation and the number of charges of the PS molecule, as well as their distribution, have a clear effect on the lipid oxidation and on the efficiency of PDI. The distinct extent of the formation of lipid hydroperoxy derivatives, depending on the PS used, is a good indicator of this process. The FOX2 assay allowed the detection of lipid peroxidation of E. coli membrane after PDI with all the five porphyrins, however, it was not the most appropriated method to quantify the relative lipid oxidation caused by PS with different efficiencies. The fatty acid analysis used to quantify the extent of lipid oxidation by the different PS provided better results. The same results were observed for the liposome model. Consequently, the model system based on liposomes is a fast and simple method that can be used for the screening of the efficiency of new PS, before proceeding with the more complex studies on bacterial models.

Deactivation of Singlet Oxygen by Titanium Dioxide in Aqueous Solution Studied by Phosphorescence Quenching with Porphyrin Photosensitizers

Deactivation of singlet oxygen (1O2) by TiO2 nanoparticles was investigated for the first time. 1O2 was produced by pulse laser-induced photosensitization with either cationic or anionic porphyrin dye. Generation and decay of 1O2 were measured by its phosphorescence at 1270 nm in the presence of seven commercially available TiO2 powders of various sizes and crystallites. To clarify the quenching mechanisms, the deactivation of the triplet excited state of porphyrin dyes (3D*) with TiO2 powders was also measured by the transient T–T absorption. The Stern–Volmer plot suggests that the quenching should take place dynamically by second-order reaction. The obtained rate constants for the deactivation of 1O2 and 3D* with TiO2 were increased with the size of the particles, which is attributable to the increase of the local concentration of 1O2 and 3D* around the TiO2 particles. The intrinsic rate constant for the deactivation of 1O2 by TiO2 was elucidated to be 1.0 × 108 M–1 s–1.

Abstract 4919: Visible/NIR-activatable prodrug strategy for treating local tumors by the combination of photodynamic therapy and local chemotherapy

Abstract Photodynamic therapy (PDT) and neoadjuvant chemotherapy have been used for treating localized tumors. However, each has its shortcomings such as limited efficacy to larger tumors and systemic side effects. We proposed a novel prodrug strategy by combining PDT and localized chemotherapy, which overcomes the problems of PDT and chemotherapy. A prodrug is composed of a photosensitizer and an anticancer drug connected via singlet oxygen (SO)-cleavable linker. Thus, SO generated by the illumination (690 nm) of the prodrug will not only directly damage tumors but also release active drug to kill surviving cancer cells. In our recent paper, we demonstrated the concept of our visible/NIR-activatable prodrug expressing the combination effect of PDT and local chemotherapy. We prepared CMP-L-CA4 where CMP = core-modified porphyrin (photosensitizer), CA4 = combretastatin A-4 (anticancer drug), and L = aminoacrylate linker (SO-cleavable linker) and its pseudo-prodrug (CMP-NCL-CA4: NCL = non-cleavable linker). CMP-L-CA4 showed desirable characteristics such as > 80% drug release in test tubes in 10 min, 6 times reduction in IC50 by illumination, and bystander effect. On the other hand, CMP-NCL-CA4 showed smaller increase in IC50 by illumination and did not show the bystander effect. Consistent with the in vitro results, CMP-L-CA4 showed significantly better antitumor effect than CMP-NCL-CA4. Recently, we developed improved prodrugs using phthalocyanine (Pc) as a photosensitizer. In our presentation, we will show our newer biological data with the prodrugs supporting our novel prodrug strategy. Citation Format: Pallavi Rajaputra, Moses Bio, Gregory Nkepang, Youngjae You. Visible/NIR-activatable prodrug strategy for treating local tumors by the combination of photodynamic therapy and local chemotherapy. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4919. doi:10.1158/1538-7445.AM2014-4919

SDS-PAGE and IR spectroscopy to evaluate modifications in the viral protein profile induced by a cationic porphyrinic photosensitizer

Reactive oxygen species can be responsible for microbial photodynamic inactivation due to its toxic effects, which include severe damage to proteins, lipids and nucleic acids. In this study, the photo-oxidative modifications of the proteins of a non-enveloped T4-like bacteriophage, induced by the cationic porphyrin 5,10,15-tris(1-methylpyridinium-4-yl)-20-(pentafluorophenyl)porphyrin tri-iodide were evaluated. Two methods were used: sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and infrared spectroscopy. SDS-PAGE analysis showed that the phage protein profile was considerably altered after photodynamic treatment. Seven protein bands putatively corresponding to capsid and tail tube proteins were attenuated and two other were enhanced. Infrared spectroscopy confirmed the time-dependent alteration on the phage protein profile detected by SDS-PAGE, indicative of a response to oxidative damage. Infrared analysis showed to be a promising and rapid screening approach for the analysis of the modifications induced on viral proteins by photosensitization. In fact, one single infrared spectrum can highlight the changes induced to all viral molecular structures, overcoming the delays and complex protocols of the conventional methods, in a much simple and cost effective way.

Anion exchange nanofiber materials activated by daylight with a dual antibacterial effect.

Anion exchange polystyrene nanofiber materials (AE) were prepared by electrospinning followed by two-step functionalization of the nanofiber surface by chlorosulfonic acid and ethylendiamine. The photoactive character of these materials was introduced through adsorption of the tetra-anionic 5,10,15,20-tetrakis-(4-sulfonatophenyl)porphyrin photosensitizer (TPPS-AE) on the nanofiber surface or by encapsulation of the nonpolar 5,10,15,20-tetraphenylporphyrin photosensitizer (AE(TPP)) into the nanofibers. Anion exchange nanofiber materials with porphyrins are characterized by a high ion-exchange capacity, photogeneration of singlet oxygen O2((1)Δg), and singlet oxygen-sensitized delayed fluorescence. Due to the photogeneration of cytotoxic O2((1)Δg), the nanofibers exhibited oxidation of the external substrates in aqueous solution and an efficient antibacterial effect when activated by simulated daylight. Adsorption of both TPPS and I(-) on the surface of AE led to the formation of more efficient I-TPPS-AE materials. Rapid photooxidation of I(-) by O2((1)Δg), and the formation of another cytotoxic species, I3(-), on the surface of the nanofibers were responsible for the increased antibacterial properties of I-TPPS-AE and the prolonged antibacterial effect in the dark.

Delivery of lipophilic porphyrin by liposome vehicles: Preparation and photodynamic therapy activity against cancer cell lines

Porphyrin photosensitizers are mostly used components in photodynamic therapy (PDT). The poor solubility of porphyrins in aqueous medium is the problem to be solved for the in vivo applications. The delivery of photosensitizers to the tumor cells using liposome vehicles can help to overcome this problem. In this work, we have first functionalized the protoporphyrin IX with lipophilic oleylamine arms and encapsulated it into 1,2 dioleyl-sn-glycero-phosphatidylcholine (DOPC) liposomes. The appropriate sizes of liposomes are about 140 nm and have the characteristic Soret and Q band absorptions at 405 nm (Soret), 507 nm, 541 nm, 577 nm and 631 nm (Q bands), respectively. In the photodynamic activity studies, the liposomal porphyrins were irradiated with light (375 nm, 10 mW) in the presence of cancer cell lines, HeLa and AGS. We have found that both liposomal porphyrins and oleylamine conjugated porphyrins are much more effective than PpIX. This result can be attributed to the drug delivery characteristic of the liposomes which plays effective role in endocytosis. We also found that, in AGS cells, liposomal PpIX-Ole induced apoptosis more than HeLa cells under light conditions.

A polymer-protein core-shell nanomedicine for inhibiting cancer migration followed by photo-triggered killing.

Migratory capacity of cancer plays a critical role in the process of metastasis. Aberrant focal adhesions activated by the phosphorylation of Src kinase enables cancer cells to anchor on its micro-environment and migrate towards biochemically favorable niche, causing metastasis. Effective blocking of the migratory capacity of cancer cells by inhibiting protein kinases and subsequent application of cytotoxic stress may provide better therapeutic outcome. Here, we report a novel core-shell nanomedicine that inhibits cancer migration by nano-shell and impart reactive oxygen stress by laser assisted photosensitization of nano-core. For this, we have optimized a polymer-protein nanoconstruct where a photosensitizer (5,10,15, 20-tetrakis(meso-hydroxyphenyl)porphyrin (mTHPP) is loaded into poly(lactic-co-glycolic acid) (PLGA) nano-core and Src kinase inhibitor (dasatinib) is loaded into albumin nano-shell. The polymer-core was prepared by electrospray technique and albumin-shell was formed by alcohol coacervation. Transmission electron microscopy studies revealed the formation of - 80 nm sized nano-core decorated with - 10 nm size nano-shell. Successful incorporation of monomeric mTHPP in nano-core resulted improved photo-physical properties and singlet oxygen release under physiological conditions compared to free-mTHPP. Core-shell nanomedicine also showed dose and time dependent cellular uptake in U87MG glioma cells. Dasatinib released from nano-shell caused down regulation of phospho-Src leading to significant impairment of cancer migration and subsequent laser assisted photosensitization of nano-core resulted in the release of reactive oxygen stress leading to apoptosis of spatially confined cancer cells. In vivo studies on Wistar rats indicated the absence of any significant toxicity caused by the intravenous administration of nanomedicine. These results clearly show the advantage of core-shell nanomedicine mediated combinatorial approach for inhibiting important cancer signalling pathways togother with imparting cytotoxic stress.

Molecular interactions and solubilization of structurally related meso-porphyrin photosensitizers by amphiphilic block copolymers (Pluronics)

The influence of four Pluronics block copolymers (i.e. F68, P123, F127, and L44) on the aggregation and solubilization of five structurally related meso-tetraphenyl porphyrin photosensitizers (PS) as model compounds for use in Photodynamic Therapy of cancer (PDT) was evaluated. Interactions between the PSs and Pluronics were studied at micromolar concentration by means of UV-Vis absorption spectrometry and by kinematic viscosity (υ) and osmolarity measurements at millimolar concentrations. Pluronic micelles were characterized by size and zeta potential (ζ) measurements. The morphology of selected PS-Pluronic assemblies was studied by atomic force microscopy (AFM). While hydrophobic 5,10,15,20-Tetrakis(4-hydroxyphenyl) porphine (THPP) seemed to be solubilized in the Pluronic micellar cores, amphiphilic di(monoethanolammonium) meso-tetraphenyl porphine disulphonate (TPPS2a) was likely bound to the micellar palisade layer. Hydrophilic PSs like 5,10,15,20-Tetrakis (4-trimethylaniliniumphenyl) porphine (TAPP) seemed to form complexes with Pluronic unimers and to be distributed among the micellar coronas. TPPS2a aggregated into a network which could be broken at Pluronic concentration ≫ cmc, but would reconstitute in the presence of tonicity adjusting agents, e.g. sodium chloride (NaCl) or glucose.