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Astrobiology Jul 2022Metal complexes of porphyrins and porphyrin-type compounds are ubiquitous in all three domains of life, with hemes and chlorophylls being the best-known examples. Their...
Metal complexes of porphyrins and porphyrin-type compounds are ubiquitous in all three domains of life, with hemes and chlorophylls being the best-known examples. Their diagenetic transformation products are found as geoporphyrins, in which the characteristic porphyrin core structure is retained and which can be up to 1.1 billion years old. Because of this, and their relative ease of detection, metalloporphyrins appear attractive as chemical biosignatures in the search for extraterrestrial life. In this study, we investigated the stability of solid chlorido(2,3,7,8,12,13,17,18-octaethylporphyrinato)iron(III) [FeCl(oep)], which served as a model for heme-like molecules and iron geoporphyrins. [FeCl(oep)] was exposed to a variety of astrobiologically relevant extreme conditions, namely: aqueous acids and bases, oxidants, heat, and radiation. Key results are: (1) the [Fe(oep)] core is stable over the pH range 0.0-13.5 even at 80°C; (2) the oxidizing power follows the order ClO > HO > ClO > HNO > ClO; (3) in an inert atmosphere, the iron porphyrin is thermally stable to near 250°C; (4) at high temperatures, carbon dioxide gas is not inert but acts as an oxidant, forming carbon monoxide; (5) a decomposition layer is formed on ultraviolet irradiation and protects the [FeCl(oep)] underneath; (6) an NaCl/NaHCO salt mixture has a protective effect against X-rays; and (7) no such effect is observed when [FeCl(oep)] is exposed to iron ion particle radiation. The relevance to potential iron porphyrin biosignatures on Mars, Europa, and Enceladus is discussed.
Topics: Heme; Hydrogen Peroxide; Iron; Metalloporphyrins; Oxidants; Porphyrins
PubMed: 35647896
DOI: 10.1089/ast.2021.0144 -
Inorganic Chemistry Jul 2022Ratiometric sensors are self-referencing constructs that are functional in cells and tissues, and the read-out is independent of sensor concentration. One strategy for...
Ratiometric sensors are self-referencing constructs that are functional in cells and tissues, and the read-out is independent of sensor concentration. One strategy for ratiometric sensing is to utilize two-color emission, where one component possesses analyte-dependent emission and the other is independent of analyte concentration, serving as an internal standard. In this way, the intensity ratio of the two components is a quantitative measure of the analyte. In this study, protein-based ratiometric oxygen sensors are prepared using the heme nitric oxide/oxygen-binding protein (H-NOX) from the thermophilic bacterium . The native heme cofactor is replaced with a Pd(II) or Pt(II) porphyrin as the oxygen-responsive phosphor. Mutagenesis is performed to incorporate a cysteine residue on the protein surface for thiol/maleimide coupling of the oxygen-insensitive dye, which serves as a Förster resonance energy transfer (FRET) donor for the porphyrin. While both Pd(II)- and Pt(II)-based sensors are responsive over biologically relevant ranges, the Pd sensor exhibits greater sensitivity at lower oxygen concentrations. Together, these sensors represent a new class of protein-based ratiometric oxygen sensors, and the modular platform allows the oxygen sensitivity to be tailored for a specific application. This proof-of-principle study has identified the key considerations and optimal methodologies to develop and subsequently refine protein-based ratiometric oxygen sensors.
Topics: Fluorescence Resonance Energy Transfer; Heme; Hemeproteins; Oxygen; Porphyrins
PubMed: 35766625
DOI: 10.1021/acs.inorgchem.2c01430 -
Journal of Photochemistry and... Jul 2021Light activatable porphyrinic photosensitizers (PSs) are essential components of anticancer and antimicrobial therapy and diagnostic imaging. However, their biological...
Light activatable porphyrinic photosensitizers (PSs) are essential components of anticancer and antimicrobial therapy and diagnostic imaging. However, their biological applications are quite challenging due to the lack of hydrophilicity and biocompatibility. To overcome such drawbacks, photosensitizers can be doped into a biocompatible polymer such as gelatin and further can be used for biomedical applications. Herein, first, a novel A4 type porphyrin PS [5,10,15,20-tetrakis(4-pyridylamidephenyl)porphyrin; TPyAPP] was synthesized via a rational route with good yield. Further, this porphyrin was encapsulated into the gelatin nanoparticles (GNPs) to develop hydrophilic phototherapeutic nanoagents (PTNAs, A4por-GNPs). Notably, the synthesis of such porphyrin-doped GNPs avoids the use of any toxic chemicals or solvents. The nanoprobes have also shown good fluorescence quantum yield demonstrating their applicability in bioimaging. Further, the mechanistic aspects of the anticancer and antimicrobial efficacy of the developed A4por-GNPs were evaluated via singlet oxygen generation studies. Overall, our results indicated porphyrin-doped biodegradable polymeric nanoparticles act as effective phototherapeutic agents against a broad range of cancer cell lines and microbes upon activation by the low-cost LED light.
Topics: Biocompatible Materials; Cell Line, Tumor; Drug Screening Assays, Antitumor; Fluorescence; HEK293 Cells; Humans; Hydrophobic and Hydrophilic Interactions; Light; Nanocapsules; Photochemotherapy; Photosensitizing Agents; Porphyrins; Quantum Theory; Reactive Oxygen Species
PubMed: 34049179
DOI: 10.1016/j.jphotobiol.2021.112209 -
Applied Microbiology and Biotechnology Dec 2024Heme is an iron-containing porphyrin compound widely used in the fields of healthcare, food, and medicine. Compared to animal blood extraction, it is more advantageous... (Review)
Review
Heme is an iron-containing porphyrin compound widely used in the fields of healthcare, food, and medicine. Compared to animal blood extraction, it is more advantageous to develop a microbial cell factory to produce heme. However, heme biosynthesis in microorganisms is tightly regulated, and its accumulation is highly cytotoxic. The current review describes the biosynthetic pathway of free heme, its fermentation production using different engineered bacteria constructed by metabolic engineering, and strategies for further improving heme synthesis. Heme synthetic pathway in Bacillus subtilis was modified utilizing genome-editing technology, resulting in significantly improved heme synthesis and secretion abilities. This technique avoided the use of multiple antibiotics and enhanced the genetic stability of strain. Hence, engineered B. subtilis could be an attractive cell factory for heme production. Further studies should be performed to enhance the expression of heme synthetic module and optimize the expression of heme exporter and fermentation processes, such as iron supply. KEY POINTS: • Strengthening the heme biosynthetic pathway can significantly increase heme production. • Heme exporter overexpression helps to promote heme secretion, thereby further promoting excessive heme synthesis. • Engineered B. subtilis is an attractive alternative for heme production.
Topics: Animals; Heme; Fermentation; Porphyrins; Anti-Bacterial Agents; Iron
PubMed: 38194135
DOI: 10.1007/s00253-023-12968-5 -
Scientific Reports May 2022Fe(III) 5,10,15,20-(tetraphenyl)porphyrin chloride (FeTPP) and Co(III) 5,10,15,20-(tetraphenyl)porphyrin chloride (CoTPP) were adsorbed on carbon Vulcan and studied as...
Fe(III) 5,10,15,20-(tetraphenyl)porphyrin chloride (FeTPP) and Co(III) 5,10,15,20-(tetraphenyl)porphyrin chloride (CoTPP) were adsorbed on carbon Vulcan and studied as electrocatalysts for the oxygen reduction reaction (ORR) before and after pyrolysis. The pyrolysis process was also simulated through ab initio molecular dynamic simulations and the minimum energy path for the O dissociation after the interaction with the metal center of the FeTPP and CoTPP were calculated. After the pyrolysis the FeTPP showed the best performances reducing O completely to HO with increased limiting current and lower overpotential. Tafel slops for the various catalysts did not change after the pyrolytic process suggesting that the mechanism for the ORR is not affected by the heat treatment. TEM images, X-ray diffraction, XPS spectroscopy, Fe Mössbauer, and DFT simulations, suggest that there is no breakdown of the macrocyclic complex at elevated temperatures, and that the macro cyclic geometry is preserved. Small variations in the Metal-O (M-O) binding energies and the M-N bond length were observed which is attributed to the dispersive interaction between the macrocycles and the irregular surface of the Vulcan substrate induced by the heat treatment and causing better interaction with the O molecule. The theoretical strategy herein applied well simulate and explain the nature of the M-N-C active sites and the performances towards the ORR.
Topics: Carbon; Chlorides; Ferric Compounds; Oxidation-Reduction; Oxygen; Porphyrins
PubMed: 35577862
DOI: 10.1038/s41598-022-11820-6 -
International Journal of Molecular... Aug 2019Recent scientific research has shown the use of chlorin, phthalocyanines, and porphyrins derivatives as photosensitizers in photodynamic therapy in the treatment of... (Review)
Review
Recent scientific research has shown the use of chlorin, phthalocyanines, and porphyrins derivatives as photosensitizers in photodynamic therapy in the treatment of various pathologies, including some of the major skin diseases. Thus, the main goal of this critical review is to catalog the papers that used these photosensitizers in the treatment of acne vulgaris, psoriasis, papillomavirus infections, cutaneous leishmaniasis, and skin rejuvenation, and to explore the photodynamic therapy mechanisms against these conditions alongside their clinical benefits.
Topics: Animals; Humans; Indoles; Isoindoles; Photochemotherapy; Photosensitizing Agents; Porphyrins; Skin; Skin Diseases; Treatment Outcome
PubMed: 31398812
DOI: 10.3390/ijms20163861 -
Journal of Cancer Research and Clinical... Sep 2022Esophageal cancer is the most common gastrointestinal tumor and is difficult to be eradicated with conventional treatment. Porphyrin-based photosensitizers (PSs)...
PURPOSE
Esophageal cancer is the most common gastrointestinal tumor and is difficult to be eradicated with conventional treatment. Porphyrin-based photosensitizers (PSs) mediated photodynamic therapy (PDT) could kill tumor cells with less damage to normal cells. As the most widely used porphyrin-based photosensitizer in clinics, Photofrin II has excellent anti-tumor effect. However, it has some disadvantages such as weak absorption at near infrared region, the complexity of components and prolonged skin photosensitivity. Here series novel 5,15-diaryl-10,20-dihalogeno porphyrin derivatives were afforded and evaluated to develop more effective and safer photosensitizers for tumor therapy.
METHODS
The photophysical properties and singlet oxygen generation rates of 5,15-diaryl-10,20-dihalogeno porphyrins (I, II) were tested. The cytotoxicity of I and II were measured by MTT assay. The pathway of cell death was studied by flow cytometry. In vivo photodynamic efficacy of I and II in Eca-109 tumor-bearing BABL/c nude mice were measured and histopathological analysis were examined.
RESULTS
5,15-Diaryl-10,20-dihalogeno porphyrins I and II were synthesized. The longest absorption wavelength of these halogenated porphyrins (λ = 660 nm) displayed a red shift around 30 nm compared to the unhalogenated porphyrins PS (λ = 630 nm). The singlet oxygen generation rates of I and II were significantly higher than PS and HMME. All PSs mediated PDT showed obvious cytotoxic effect against Eca-109 cells compared to HMME in vitro and in vivo. Among these PSs, II exhibited appropriate absorption in the phototherapeutic window, higher O generation rate (k = 0.0061 s), the strongest phototoxicity (IC = 0.4 μM), lower dark toxicity, high generation of intracellular ROS in Eca-109 cells and excellent photodynamic anti-tumor efficacy in vivo. Besides, cell necrosis was induced by compound II mediated PDT.
CONCLUSION
All new compounds have obvious photodynamic anti-esophageal cancer effects. Among them, the photosensitizer II showed excellent efficacy in vitro and in vivo, which has the potential to become a photodynamic anti-tumor drug.
Topics: Animals; Antineoplastic Agents; Cell Line, Tumor; Esophageal Neoplasms; Mice; Mice, Nude; Photochemotherapy; Photosensitizing Agents; Porphyrins; Singlet Oxygen
PubMed: 35522290
DOI: 10.1007/s00432-022-04037-7 -
Journal of Enzyme Inhibition and... Dec 2020With the development of photodynamic therapy (PDT), remarkable studies have been conducted to generate photosensitisers (PSs), especially porphyrin PSs. A variety of... (Review)
Review
With the development of photodynamic therapy (PDT), remarkable studies have been conducted to generate photosensitisers (PSs), especially porphyrin PSs. A variety of chemical modifications of the porphyrin skeleton have been introduced to improve cellular delivery, stability, and selectivity for cancerous tissues. This review aims to highlight the developments in porphyrin-based structural modifications, with a specific emphasis on the role of PDT in anticancer treatment and the design of PSs to achieve a synergistic effect on multiple targets.
Topics: Animals; Antineoplastic Agents; Cell Proliferation; Drug Design; Drug Screening Assays, Antitumor; Humans; Molecular Structure; Neoplasms; Photochemotherapy; Photosensitizing Agents; Porphyrins
PubMed: 32329382
DOI: 10.1080/14756366.2020.1755669 -
Advanced Healthcare Materials Feb 2022The treatment of pathogenic bacterial infection has long been the most serious threat to human life and attracted widespread attention. Herein, a supramolecular...
The treatment of pathogenic bacterial infection has long been the most serious threat to human life and attracted widespread attention. Herein, a supramolecular photosensitizer platform based on carboxylatopillar[5]arene (CP5) and tetrafluorophenyl porphyrin functionalized with a quaternary ammonium group (TFPP-QA) for combating bacteria and dispersing biofilm via photodynamic treatment is constructed. By introducing the host macrocycle CP5 and host-guest interaction, the supramolecular photosensitizer has great biocompatibility and acid responsiveness. On the one hand, the acid-triggered dissociation of TFPP-QA/CP5 could induce the porphyrin photosensitizer to target bacterial cells and disrupt the charge balance of bacterial membranes, enhance the permeability of the bacterial membrane. On the other hand, the TFPP-QA/CP5 antibacterial platform possesses superb reactive oxygen species (ROS) generation capability under light irradiation, leading to enhanced photodynamic antibacterial efficacy. The in vitro and in vivo studies show that the supramolecular photosensitizers exhibit high antibacterial efficiency and biofilm dissipation effect under 660 nm light irradiation. Therefore, it is anticipated that the rational design and integration of photosensitizers and quaternary ammonium compounds through the supramolecular strategy would provide a promising prospect for clinical photodynamic antimicrobial therapy.
Topics: Bacterial Infections; Biofilms; Calixarenes; Humans; Photochemotherapy; Photosensitizing Agents; Porphyrins; Quaternary Ammonium Compounds
PubMed: 34787954
DOI: 10.1002/adhm.202102015 -
International Journal of Molecular... Aug 2020Porphyrins have planar and conjugated structures, good optical properties, and other special functional properties. Owing to these excellent properties, in recent years,... (Review)
Review
Porphyrins have planar and conjugated structures, good optical properties, and other special functional properties. Owing to these excellent properties, in recent years, porphyrins and their analogues have emerged as a multifunctional platform for chemical sensors. The rich chemistry of these molecules offers many possibilities for metal ions detection. This review mainly discusses two types of molecular porphyrin and porphyrin composite sensors for metal ions detection, because porphyrins can be functionalized to improve their functional properties, which can introduce more chemical and functional sites. According to the different application materials, the section of porphyrin composite sensors is divided into five sub-categories: (1) porphyrin film, (2) porphyrin metal complex, (3) metal-organic frameworks, (4) graphene materials, and (5) other materials, respectively.
Topics: Fluorescent Dyes; Ions; Metal-Organic Frameworks; Metals; Molecular Probes; Porphyrins
PubMed: 32823943
DOI: 10.3390/ijms21165839