Distribution Of Porphyrins Research Articles

Photochemical and Sono-Photochemical Studies of Zn (II) Porphyrin-conjugated Chitosan Hydrogels for Enhanced Singlet Oxygen Generation

This study explores the synthesis, characterization, photochemical, and sono-photochemical properties of covalently conjugated porphyrin-chitosan hydrogels for potential application in photodynamic therapy (PDT) and sono-photodynamic therapy (SPDT). The efficient production of singlet oxygen, a crucial reactive oxygen species (ROS) in these therapies, was investigated. Zinc(II) porphyrins 1 and 2 were synthesized by metal insertion to free based porphyrins and covalently linked to chitosan via Schiff-base reaction to produce chitosan hydrogel CS-1 and CS-2 (conjugation via phenylacetylene spacer). The synthesized compounds were characterized using standard spectroscopic techniques, confirming successful conjugation. Scanning electron microscopy (SEM) analysis demonstrating the homogeneous distribution of porphyrins within the hydrogel matrix. Photophysical and photochemical properties, including ground state absorption and singlet oxygen generation, were evaluated for both porphyrin complexes and chitosan-conjugated hydrogels in DMSO. The porphyrin-hydrogel structures showed superior singlet oxygen generation efficiency. Sono-photochemical studies showed further enhanced singlet oxygen generation, with the highest quantum yield (ΦΔ= 0.81) observed for the chitosan hydrogel CS-2. The results demonstrated enhanced singlet oxygen generation in the hydrogel structures, particularly under simultaneous ultrasound and light irradiation, indicating their potential efficacy in PDT and SPDT applications. Additionally, photo degradation studies revealed the stability of the synthesized compounds under light irradiation. These findings highlight the potential of porphyrin-conjugated chitosan hydrogels as effective photosensitizers for PDT and SPDT applications.

Porphyrin Photosensitizers into Polysaccharide-Based Biopolymer Hydrogels for Topical Photodynamic Therapy: Physicochemical and Pharmacotechnical Assessments.

Photodynamic therapy (PDT) is an emerging treatment modality that utilizes light-sensitive compounds, known as photosensitizers, to produce reactive oxygen species (ROS) that can selectively destroy malignant or diseased tissues upon light activation. This study investigates the incorporation of two porphyrin structures, 5-(4-hydroxy-3-methoxyphenyl)-10,15,20-tris-(4-acetoxy-3-methoxyphenyl) porphyrin (P2.2.) and 5,10,15,20-tetrakis-(4-acetoxy-3-methoxyphenyl) porphyrin (P2.1.), into hydroxypropyl cellulose (HPC) hydrogels for potential use in topical photodynamic therapy (PDT). The structural and compositional properties of the resulting hydrogels were characterized using advanced techniques such as Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis (TGA), atomic force microscopy (AFM), UV-Visible (UV-Vis) spectroscopy, and fluorescence spectroscopy. FTIR spectra revealed a slight shift of the main characteristic absorption bands corresponding to the porphyrins and their interactions with the HPC matrix, indicating successful incorporation and potential hydrogen bonding. XRD patterns revealed the presence of crystalline domains within the HPC matrix, indicating partial crystallization of the porphyrins dispersed within the amorphous polymer structure. TGA results indicated enhanced thermal stability of the HPC-porphyrin gels compared to 10% HPC gel, with additional weight loss stages corresponding to the thermal degradation of the porphyrins. Rheological analysis showed that the gels exhibited pseudoplastic behavior and thixotropic properties, with minimal impact on the flow properties of HPC by P2.1., but notable changes in viscosity and shear stress with P2.2. incorporation, indicating structural modifications. AFM imaging revealed a homogeneous distribution of porphyrins, and UV-Vis and fluorescence spectroscopy confirmed the retention of their photophysical properties. Pharmacotechnical evaluations showed that the hydrogels possessed suitable mechanical properties, optimal pH, high swelling ratios, and excellent spreadability, making them ideal for topical application. These findings suggest that the porphyrin-incorporated HPC hydrogels have significant potential as effective therapeutic agents for topical applications.

Protoporphyrin IX metabolism mediated via translocator protein (CgTspO) involved in orange shell coloration of pacific oyster (Crassostrea gigas)

Mollusc shell color polymorphism is influenced by various factors. Pigments secreted in vivo by animals play a critical role in shell coloration. Among the different shell-color hues, orange pigmentation has been partially attributed to porphyrins. However, the detailed causal relationship between porphyrins and orange-shell phenotype in molluscs remains largely unexplored. The various strains of Pacific oyster (Crassostrea gigas) with different shell color provide useful models to study the molecular regulation of mollusc coloration. Accordingly, oysters with orange and gold-shells, exhibiting distinct porphyrin distributions, were selected for analysis of total metabolites and gene expression profile through mantle metabolomic and transcriptomic studies. Translocator protein (TspO) and protoporphyrin IX (PPIX) were identified as potential factors influencing oyster shell-color. The concentration of PPIX was measured using HPLC, while expression profiling of CgTspO was analyzed by qPCR, in situ hybridization, Western blotting, and immunofluorescence techniques. Moreover, the roles of CgTspO in regulating PPIX metabolism and affecting the orange-shell-coloration were investigated in vitro and in vivo. These studies indicate that PPIX and its associated metabolic protein, CgTspO may serve as new regulators of orange-shell-coloration in C. gigas. Data of this study offer new insights into oyster shell coloration and enhancing understandings of mollusc shell color polymorphism.

Morphology study of nickel and vanadium in asphaltenes via hydropyrolysis

The morphology of nickel and vanadium compounds in the asphaltenes were investigated via hydropyrolysis with the help of inductively coupled plasma mass spectrometer (ICP-MS), ultraviolet-visible (UV-Vis), high-temperature gas chromatography atomic emission detection (HT GC-AED), and positive-ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (+ESI FT-ICR MS). The results showed that the toluene soluble yields of products decreased from 64% to 19% as the hydropyrolysis temperature increased from 330 to 410 °C, while the abundance of nickel and vanadium compounds detected by GC-AED increased significantly. The molecular composition distribution of nickel and vanadyl porphyrins showed rhythmic changes with different temperatures in the hydropyrolysis of asphaltenes.

Identification and characterization of key haem pathway genes associated with the synthesis of porphyrin in Pacific oyster (Crassostrea gigas).

Molluscs exhibit diverse shell colors. The molecular regulation of shell coloration is however not well understood. To investigate the connection of shell coloration with pigment synthesis, we analyzed the distribution of porphyrins, a widespread group of pigments in nature, in four Pacific oyster strains of different shell colors including black, orange, golden, and white. The porphyrin distribution was analyzed in oyster mantles and shells by fluorescence imaging and UV spectrophotometer. The results showed that red fluorescence emitted by porphyrins under the UV light was detected only on the nacre of the orange-shell strain and mantles of orange, black and white-shell strains. Extracts from newly deposit shell, nacre and mantle tissue from orange-shell specimens showed peaks in UV-vis spectra that are characteristic of porphyrins, but these were not observed for the other shell-color strains. In addition, genes of the haem synthetic pathway were isolated and characterized. Phylogenetic analysis of CgALAS, CgALAD, CgPBGD, CgUROS, and CgUROD provide further evidence for a conserved genetic pathway of haem synthesis during evolution. Differential expression of the haem genes expressed in mantle tissues support these findings and are consistent with porphyrins being produced by the orange strain only. Tissue in situ hybridization demonstrated the expression of these candidate genes at the outer fold of C. gigas mantles where shell is deposited. Our studies provide a better understanding of shell pigmentation in C. gigas and candidate genes for future mechanistic analysis of shell color formation in molluscs.

Simultaneous Detection of Vanadyl, Nickel, Iron, and Gallium Porphyrins in Marine Shales from the Eagle Ford Formation, South Texas

Metalloporphyrins in immature shales of the Late Cretaceous Eagle Ford Formation from South Texas were analyzed by positive-ion electrospray ionization (ESI) Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Vanadyl, nickel, iron, and gallium porphyrins were detected in a single mass spectrum. The iron porphyrins were most abundant, followed by vanadyl, nickel, and gallium porphyrins, consistent with the metal contents determined by elemental analysis. The distribution of porphyrins shows that deoxophylloerythroetio (DPEP) porphyrins, dicyclic-deoxophylloerythroetio (di-DPEP) porphyrins, and porphyrins containing oxygen functional groups are the main components. The detection of oxygen-containing porphyrins, such as iron porphyrins with formulas of CnHmN4FeO, CnHmN4FeO2, and CnHmN5FeO2, would offer new clues of petroporphyrins formation mechanism from biological sources, such as chlorophylls and hemes. To our knowledge, this reports for the first time the presence of oxygen-containing iron porphyrins and gallium porphyrins in geological samples other than coals and lignites. The discovery of these petroporphyrins could provide additional insights into the diagenetic pathway of petroporphyrins and novel applications in petroleum geochemistry/exploration and oil refining. The composition of metalloporphyrins may potentially provide clues to decipher the redox conditions during deposition in the Eagle Ford Formation and provide better understanding of the Oceanic Anoxic Event 2 (OAE-2).

Distribution of vanadium and vanadyl porphyrins during fractionation of resins of heavy sulfurous oils

ABSTRACTFeatures of the content and distribution of vanadium and vanadyl porphyrins in the fractions of resins, which were obtained by separation using column chromatography on silica, have been studied on heavy sulfurous oils of various deposits of the Volga–Ural basin (Russia). The difference of the vanadium and vanadyl porphyrin contents in the fractions of oils of various production complexes has been shown. Features of structural–group composition and predominant types of vanadyl porphyrins in the fractions of resins have been determined.

Simultaneous quantitative analysis of Ni, VO, Cu, Zn and Mn geoporphyrins by liquid chromatography-high resolution multistage mass spectrometry: Method development and validation

A method is described for the identification and quantification of Cu, Ni, VO, Zn and Mn metalloporphyrins in geological samples using a high performance liquid chromatography (HPLC) system coupled to a high resolution Thermo Orbitrap XL mass spectrometer (MS). The linear correlation of the detector response to the compound concentrations in Cu, Ni, VO, Zn and Mn porphyrin standards (R2 values between 0.9975 and 0.9994), verified the suitability of the methodology for the quantification of these compounds. Furthermore, the method was validated by the analysis of complex porphyrin distributions in geological sample isolates from the Australian Toolebuc Formation and Bight Basin. By using the high resolution of the Orbitrap MS detector it was not only possible to reproduce the porphyrin distributions reported from previous analyses of the same isolates, but also to identify and resolve a range of additional compounds such as an iso-butyl C34 VO porphyrin indicative of palaeoenvironmental photic zone euxinia and several Cu and Zn porphyrins. The methodology described here provides a new high resolution tool for routine analysis of complex metalloporphyrin distributions in geological sample extracts, enabling the simultaneous quantitative analysis of Cu, Ni, VO, Zn and Mn porphyrins without the need of prior de-metalation or further fractionation of the porphyrin extract. The high resolution of the Orbitrap MS combined with the ability to perform multistage mass spectrometry leads to a significant improvement in compound detection and identification, which shows a high potential in the analysis of low abundance porphyrins, such as high-molecular-weight porphyrins with extended alkyl side-chains.

Controls on the stratigraphic distribution and nitrogen isotopic composition of zinc, vanadyl and free base porphyrins through Oceanic Anoxic Event 2 at Demerara Rise

The Cenomanian–Turonian black shales of the Demerara Rise (DR) contain a wide range of tetrapyrroles and allow porphyrin analysis through Oceanic Anoxic Event 2 (OAE 2), making this site unique. The sediments provide an excellent opportunity to study the factors controlling the stratigraphic distribution and N isotopic composition of porphyrins. Three C33 bicycloalkanoporphryins (BiCAPs) are present as free bases (FBs) and as complexes with Zn and VO in quantities sufficient for compound-specific isotope analysis (CSIA) and were the focus of this study. The stratigraphic distribution of BiCAPs is controlled, foremost, by metal availability rather than sedimentary Eh/pH conditions or post depositional maturity. Titration of the local water column metal reservoir with sulfide and organic matter during OAE 2 resulted in a high concentration of FB BiCAPs and a very low concentration of metallo-BiCAPs. Conversely, high metal concentration occurs in sediments above and below the OAE, and Zn and VO porphyrin abundances mirror bulk metal concentration. The highest total concentration of porphyrins was where metal concentration was highest, suggesting that porphyrin preservation is enhanced by the increased stability of metal complexes. Unexpectedly, the total concentration of porphyrins was lowest during the heart of OAE 2, in an interval of higher total organic carbon (TOC) content, where enhanced preservation would be expected; we suggest this was the result of decreased preservation of extractable tetrapyrroles in the absence of available metals. The high reactivity of Zn2+ with sulfide limited the formation of Zn complexes to the non-sulfidic regions in the water column or at the sediment/water interface. The formation of VO porphyrins occurred exclusively within the sediments from available FBs or through transmetallation with other metallo-BiCAPS (Zn, Ni, Cu).The formation of the metal complexes had a N isotope effect. We observed significant differences in the δ15N values of the three most abundant BiCAPs. VO BiCAPs were systematically 15N-depleted by an average of 2.5±1.5‰ relative to FBs, and Zn BiCAPs were equivalent to FB BiCAPs within error (15N enriched by+0.1‰) but were variable (±1.5‰). The δ13C values of the Zn, VO and FB BiCAPs were equivalent, suggesting that the three compounds share a common chlorophyll source, in agreement with structural data. The significant difference in δ15N values between the VO and FB BiCAPs suggests that δ15N values of VO porphyrins are controlled by N isotopic effects during VO porphyrin formation. Under experimental conditions, the formation of Zn octaethylporphyrin had a fractionation (εproduct/reactant −3.9) consistent with the differences between FB and VO BiCAPs, supporting a diagenetic origin for the differences in δ15N. The δ15N values of the porphyrins in these ancient sediments have been used to reconstruct the δ15N value of the primary phototrophic biomass and the ecological balance of chlorophyll a producing organisms via the εpor proxy. If the δ15N values of porphyrins are indeed altered by metal–ligand reactions, the application for paleoenvironmental reconstruction may require a more complete analysis of the range of metalloporphyrins in a given structural class. The covariance of bulk, BiCAP, porphyrin class and kerogen δ15N through OAE 2 suggests that the variability in δ15N reflects primary N cycle dynamics and that the εpor proxy can be viable in ancient sediments despite these complexities.

Robust rat pulmonary radioprotection by a lipophilic Mn N-alkylpyridylporphyrin, MnTnHex-2-PyP5+

With the goal to enhance the distribution of cationic Mn porphyrins within mitochondria, the lipophilic Mn(III)meso-tetrakis(N-n-hexylpyridinium-2-yl)porphyrin, MnTnHex-2-PyP5+ has been synthesized and tested in several different model of diseases, where it shows remarkable efficacy at as low as 50µg/kg single or multiple doses. Yet, in a rat lung radioprotection study, at higher 0.6–1mg/kg doses, due to its high accumulation and micellar character, it became toxic. To avoid the toxicity, herein the pulmonary radioprotection of MnTnHex-2-PyP5+ was assessed at 50µg/kg. Fischer rats were irradiated to their right hemithorax (28Gy) and treated with 0.05mg/kg/day of MnTnHex-2-PyP5+ for 2 weeks by subcutaneously-implanted osmotic pumps, starting at 2h post-radiation. The body weights and breathing frequencies were followed for 10 weeks post-radiation, when the histopathology and immunohistochemistry were assessed. Impact of MnTnHex-2-PyP5+ on macrophage recruitment (ED-1), DNA oxidative damage (8-OHdG), TGF-β1, VEGF(A) and HIF-1α were measured. MnTnHex-2-PyP5+ significantly decreased radiation-induced lung histopathological (H&E staining) and functional damage (breathing frequencies), suppressed oxidative stress directly (8-OHdG), or indirectly, affecting TGF-β1, VEGF (A) and HIF-1α pathways. The magnitude of the therapeutic effects is similar to the effects demonstrated under same experimental conditions with 120-fold higher dose of ~5000-fold less lipophilic Mn(III)meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin, MnTE-2-PyP5+.

Cellular stress induced by photodynamic reaction with CoTPPS and MnTMPyPCl5 in combination with electroporation in human colon adenocarcinoma cell lines (LoVo and LoVoDX)

Two porphyrins, CoTPPS and MnTMPyPCl5, were tested for their photodynamic activity and potential novel use in a therapy of human cancers. We investigated an effect of photodynamic reaction (PDR), electroporation (EP) and their combination (electro-photodynamic reaction [EP-PDR]) on human colon adenocarcinoma cell lines (LoVo and resistant to doxorubicin LoVoDX), human breast adenocarcinoma (wild type MCF-7/WT and resistant to doxorubicin MCF-7/DOX), and human melanoma (Me45). The efficiency of macromolecules transport was examined with cytofluorymetry by assessing the degree of propidium iodide (PI) penetration. Additionally, cellular ultrastructure after EP was evaluated. We determined cyto- and photo-cytotoxic effect on the cells viability (MTT assay) after standard PDR and PDR combined with EP. Intracellular distribution and mitochondrial colocalization of both porphyrins was also performed. The experiments proved that both complexes exhibit desirable photodynamic properties on LoVo LoVoDX cells, and EP effectively supports photodynamic method in this type of cancer. The application of EP provided shorter time of incubation (only 10min) and enhanced effect of applied therapy. The porphyrins did not affect the MCF-7 and Me45 cell lines.

Comprehensive pharmacokinetic studies and oral bioavailability of two Mn porphyrin-based SOD mimics, MnTE-2-PyP5+ and MnTnHex-2-PyP5+

The cationic, ortho Mn(III) N-alkylpyridylporphyrins (alkyl=ethyl, E, and n-hexyl, nHex) MnTE-2-PyP5+ (AEOL10113, FBC-007) and MnTnHex-2-PyP5+ have proven efficacious in numerous in vivo animal models of diseases having oxidative stress in common. The remarkable therapeutic efficacy observed is due to their: (1) ability to catalytically remove O2•− and ONOO− and other reactive species; (2) ability to modulate redox-based signaling pathways; (3) accumulation within critical cellular compartments, i.e., mitochondria; and (4) ability to cross the blood–brain barrier. The similar redox activities of both compounds are related to the similar electronic and electrostatic environments around the metal active sites, whereas their different bioavailabilities are presumably influenced by the differences in lipophilicity, bulkiness, and shape. Both porphyrins are water soluble, but MnTnHex-2-PyP5+ is approximately 4 orders of magnitude more lipophilic than MnTE-2-PyP5+, which should positively affect its ability to pass through biological membranes, making it more efficacious in vivo at lower doses. To gain insight into the in vivo tissue distribution of Mn porphyrins and its impact upon their therapeutic efficacy and mechanistic aspects of action, as well as to provide data that would ensure proper dosing regimens, we conducted comprehensive pharmacokinetic (PK) studies for 24h after single-dose drug administration. The porphyrins were administered intravenously (iv), intraperitoneally (ip), and via oral gavage at the following doses: 10mg/kg MnTE-2-PyP5+ and 0.5 or 2mg/kg MnTnHex-2-PyP5+. Drug levels in plasma and various organs (liver, kidney, spleen, heart, lung, brain) were determined and PK parameters calculated (Cmax, C24h, tmax, and AUC). Regardless of high water solubility and pentacationic charge of these Mn porphyrins, they are orally available. The oral availability (based on plasma AUCoral/AUCiv) is 23% for MnTE-2-PyP5+ and 21% for MnTnHex-2-PyP5+. Despite the fivefold lower dose administered, the AUC values for liver, heart, and spleen are higher for MnTnHex-2-PyP5+ than for MnTE-2-PyP5+ (and comparable for other organs), clearly demonstrating the better tissue penetration and tissue retention of the more lipophilic MnTnHex-2-PyP5+.

Enhanced uptake and photoactivation of topical methyl aminolevulinate after fractional CO2 laser pretreatment

Photodynamic therapy (PDT) of thick skin lesions is limited by topical drug uptake. Ablative fractional resurfacing (AFR) creates vertical channels that may facilitate topical PDT drug penetration and improve PDT-response in deep skin layers. The purpose of this study was to evaluate whether pre-treating the skin with AFR before topically applied methyl aminolevulinate (MAL) could enable a deep PDT-response. Yorkshire swine were treated under general anesthesia with a fractional CO(2) laser using stacked single pulses of 3 milliseconds, 91.6 mJ per pulse and subsequent topical MAL application for 3 hours (Metvix®). Red light (LED arrays) was then delivered at fluences of 37 and 200 J/cm(2). Fluorescent photography and microscopy was used to quantify MAL-induced porphyrin distribution and PDT-induced photobleaching at the skin surface and five specific depths down to 1,800 µm. Laser-ablated channels were approximately 1,850 µm deep, which significantly increased topical MAL-induced porphyrin fluorescence (hair follicles, dermis, P < 0.0001) and PDT response, both superficially and deep, versus topical MAL application alone. The fraction of porphyrin fluorescence lost by photobleaching was slightly less after 37 J/cm(2) than after 200 J/cm(2) (overall median values 67-90%; 37 vs. 200 J/cm(2), P > 0.05 for all but one comparison). Photobleaching was steady throughout skin layers and did not vary significantly with skin depth at either LED fluence (P > 0.05). AFR greatly facilitates topical MAL-induced porphyrins and the fraction of photobleached porphyrins is similar for superficial and deep skin. These observations are consistent with AFR-enhanced uptake of MAL, increased porphyrin synthesis, and photodynamic activation of deep porphyrins even at the lower fluence of 37 J/cm(2), widely used in clinical practice. AFR appears to be a clinically practical means for improving PDT deep into the skin. Clinical studies are suggested to evaluate selectivity in targeting dysplastic cell types.

Intracutaneous ALA photodynamic therapy: Dose-dependent targeting of skin structures

Photodynamic therapy (PDT) using topical aminolevulinic acid (ALA) depends on local drug uptake, metabolism to porphyrins, and depth of light penetration using different wavelengths. Topical ALA-PDT has limited depth of drug penetration. We studied induced porphyrin distribution and PDT after intradermal ALA administration using different drug concentrations followed by high-fluence red light irradiation. Intradermal injections (∼2 mm deep) of ALA concentrations from 0.0005% to 1% were studied in swine to evaluated porphyrin fluorescence before PDT and clinical and histological damage 24 hours after PDT. Porphyrin accumulation was measured by fluorescence microscopy of frozen section. PDT was performed 3 hours after intradermal injections using a 635 nm LED array at a fluence of 200 J/cm2 . Skin responses to PDT were observed grossly and by histology (blind evaluation). Intradermal ALA caused porphyrin accumulation in epidermis, hair follicles (HF), sebaceous glands (SG), sweat glands (eccrine glands, EG and apocrine glands, AG), and subcutaneous fat. Significant differences of fluorescence intensity were observed between different skin structures (P < 0.05), but there was no significant difference comparing HF to SG; epidermis with either HF or SG; and dermis with fat (P > 0.05). Intradermal ALA is potent. ALA concentrations ≥0.25% followed by red light exposures caused a very intense vascular PDT reaction. Moderate doses of injected ALA concentration (∼0.06%), selectively targeted EG. Low doses (≤0.016%) targeted fat; producing fat necrosis with minimal inflammation, manifested both clinically and histologically. In contrast to topical ALA-PDT, intradermal ALA-PDT can effectively photosensitize deep skin structures. Potentially, intradermal ALA-PDT using various ALA concentrations may be useful for treating vascular lesions (malformations, hemangiomas, tumors), EG/AG disorders, fat or deep targets in skin.

Determination of volatile nickel and vanadinum species in crude oil and crude oil fractions by gas chromatography coupled to inductively coupled plasma mass spectrometry

A new method using Gas Chromatography (GC) coupled to Inductively Coupled Plasma Mass Spectrometry (ICPMS) was developed for the determination of nickel and vanadium species in crude oil and its fractions. The method requires a transfer line and ICP injector uniformly heated to at least 350 °C (662 °F) and rapid transfer of separated species from the GC to the ICPMS in heated Argon gas. The Ni and V distributions determined by this method revealed the metal fingerprint of each metal in different crude oils. Fingerprints and yield distribution (boiling point vs. amount) of Nickel and Vanadium porphyrins are shown in this work.

Effect of overall charge and charge distribution on cellular uptake, distribution and phototoxicity of cationic porphyrins in HEp2 cells

Five cationic porphyrins bearing one to four – N ( CH 3 ) 3 + groups linked to the p-phenyl positions of 5,10,15,20-tetraphenylporphyrin (TPP) were synthesized in order to study the effect of overall charge and its distribution on the cellular uptake, phototoxicity and intracellular localization using human carcinoma HEp2 cells. The di-cationic porphyrins DADP-o and DADP-a accumulated the most within cells and preferentially localize within vesicular compartments and in mitochondria. Of these two only DADP-a was phototoxic to the cells (IC 50 = 3 μM at 1 J/cm 2). The mono-cationic porphyrin MAP was found to be the most phototoxic of the series, and it localized mainly in lipid membranes, including the plasma membrane, ER, mitochondria, and Golgi. Both the tri-cationic porphyrin TRAP and the tetra-cationic porphyrin TEAP localized subcellularly mainly in the mitochondria, but of the two only TEAP showed moderate phototoxicity (IC 50 = 8 μM at 1 J/cm 2). Our results suggest that MAP is the most promising PDT photosensitizer, and that both DADP-o and TRAP might find application as transport vehicles for therapeutics into cells.

Mass Spectrometry of Metalloporphyrins in Egyptian Oil Shales from Red Sea Area

Metalloporphyrins, extracted from asphaltene and maltene fractions of some Egyptian oil shales (Abu-Shegeili, El-Beida, El-Nakheil, and Abu-Tundub in the Red Sea area) by means of adsorption column chromatography and TLC, were subjected to mass spectrometry in order to elucidate the structure of different types of VO, Ni, or Fe porphyrins. Metalloporphyrins were not detected in maltene or asphaltene fractions of Abu-Shegeili oil shale. The mass spectra appeared as a truncated series of mass numbers, which is characteristic of geo-porphyrins in sediments or oil shales. The data indicated that the five types of porphyrins (Etio, DPEP, BEtio, BDPEP, and THBD) with carbon numbers ranging from C20 to C50 were present in considerable detection levels. Based on mass spectrometric data, the major components of metalloporphyrins (VO, Ni, or Fe) were identified and their chemical structures were suggested. The occurrence and distribution of VO, Ni, and Fe porphyrins were interpreted from a geochemical point of view, particularly maturation levels and oil-gas potentials of kerogens.

Infrared Spectroscopic Signatures of Phase Segregation in P3HT−Porphyrin Blends

Phase segregation of 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphine ruthenium(II)carbonyl (RuOEP) and regioregular poly(3-hexylthiophene-2,5-diyl) (P3HT) in thin films is investigated with infrared and UV-visible spectroscopies as well as transmission electron microscopy (TEM). The Fourier transform infrared (FTIR) spectrum of the ruthenium-bound CO symmetric stretching mode exhibits significant changes as these films are annealed in solvent vapors. The development of multiple inhomogeneously broadened microenvironments is observed, and UV-visible spectra and TEM support a model of homogeneous porphyrin distribution throughout the P3HT films that gradually becomes more heterogeneous as the P3HT and RuOEP molecules phase segregate. A complete model for the phase segregation process experienced by the embedded RuOEP is proposed to explain the collective experimental observations.

Porphyrin distribution after topical aminolevulinic acid in a novel porcine model of sebaceous skin

Aminolevulinic acid photodynamic therapy (ALA-PDT) depends on drug metabolism into porphyrins. Clinically, ALA-PDT has been used with a wide range of protocols for treating both epidermal and dermal targets, despite limited understanding of porphyrin biodistribution over time. We studied porphyrin accumulation after topical application of ALA in vivo, and also describe the porcine ear as a new animal model to study adnexal glands. The microanatomy of anterior ear skin of swine was measured. Topical 20% ALA in water/ethanol was applied under occlusion. Biopsies taken after 5, 10, 15, and then every 15 minutes for a total of 3 hours were examined by fluorescence microscopy of frozen sections to assess accumulation and distribution of porphyrins. Porphyrin fluorescence of digital photomicrograph images was not visually apparent until 30-45 minutes after application, although quantitative pixel analysis showed a statistically significant increase in epidermal fluorescence only 15 minutes after ALA application. From 30 to 120 minutes, epidermis, hair follicles (HF), and sebaceous glands (SG) became progressively more fluorescent. Eccrine gland fluorescence began to be detected after 30 minutes; SG showed fluorescence starting at 45-75 minutes. Fluorescence in all sites reached maximum intensity from 75 to 180 minutes of incubation. There was a trend for HF and SG to express stronger fluorescence compared with epidermis and eccrine glands. Anterior pig ear skin is microanatomically similar to human sebaceous skin. The time-dependent accumulation of porphyrins in pilosebaceous units and eccrine glands in this model suggests other routes of uptake of topical ALA in addition to the trans-epidermal route. Apparently, time interval between ALA application and light exposure could be optimized for different uses of ALA-PDT.

Time‐resolved Microspectrofluorometry and Fluorescence Imaging Techniques: Study of Porphyrin‐mediated Cellular Uptake of Oligonucleotides

Time-resolved confocal microspectrofluorometry and fluorescence microscopy imaging were applied to monitor the cellular uptake of fluorescent-labeled oligonucleotides (ONs) delivered by a porphyrin molecule. The fate of porphyrin-ON complexes inside living cells has also been monitored. Due to intrinsic fluorescence of the porphyrin and sensitivity of its characteristics to microenvironment, multicomponent analysis of time-resolved fluorescence provides unique information about stability of the porphyrin-ON complexes, ON interactions with their target sequences, and ON and porphyrin distributions after delivery inside the cells. Time-resolved confocal microspectrofluorometry indeed delivers additional information compared with fluorescence confocal microscopy imaging widely employed to study ON uptake.