There is a growing demand for clean-label products. This study aimed to obtain a food-grade coloring ingredient for meat products based on the formation of Zn-protoporphyrin from porcine livers, thus contributing to the development of nitrite-free products. First, the effects of sodium disulfite, and acetic, ascorbic, and lactic acids on Zn-protoporphyrin formation and total microbial count were studied. The combination of ascorbic and acetic acid resulted in a higher Zn-protoporphyrin content than acetic acid alone and maintained microbial levels (ca. 3 log CFU/mL). Second, a response surface methodology was used to maximize Zn-protoporphyrin while maintaining microbiological food standards. The effects of pH (4.2–5.4), incubation time (3–30 h), and temperature (25–50 ºC) were studied. The selected conditions for Zn-protoporphyrin formation involved anaerobic incubation at pH 4.8 and 45 °C for 24 h. The safety was validated through challenge testing for relevant pathogens (Listeria monocytogenes, Salmonella spp., and Clostridium perfringens). A significant reduction (> 6 log units) was observed for L. monocytogenes and Salmonella, whereas C. perfringens spores remained at inoculated levels. The optimized procedure is proven to be microbiologically safe, and it is proposed to improve the color of nitrite-free meat products.

Electrochemical impedance (EI) measurements were performed to evaluate the nylon 66/-tetra-(para-aminophenyl) porphyrin (H₂T(p-NH₂)PP)/graphene oxide (GO) film coating on stainless steel and compared to the nylon/H₂T(p-NH₂)PP and nylon/GO film samples using 1M H₂SO₄ as electrolyte. The nylon/H₂T(p-NH₂)PP and nylon/GO composite films showed high electrochemical impedance in the order of 109 ohm-cm² and a system controlled by mass transfer, product of a diffusion process at low frequencies with a resistance up to 5 orders of magnitude, indicating the diffusion of protons through the coating and a decrease in the metal dissolution. Otherwise, the nylon/H₂T(p-NH₂)PP/GO film compound evaluated show good ionic conductivity and electrochemical stability in the acid environment, acting porphyrin as a catalyst to the passage of protons through the film, reducing its electrochemical impedance up to 7 orders of magnitude with respect to the compounds nylon/H₂T(p-NH₂)PP and nylon/GO. Likewise, good capacitance values are also shown by modifying the concentrations of porphyrin and GO reinforcing materials. These properties are important for technological applications, such as anticorrosion coating for bipolar plates or membrane in a fuel cell type PEM, super-capacitors, etc.

The photophysical properties of Cu(II) complexes with 5,10,15,20-meso-tetrakis(phenyl)porphyrin and 5,10,15,20-meso-tetrakis(N-methylpyridium-4-yl)porphyrin were examined by luminescence and femtosecond time-resolved absorbance methods respectively. These studies were supported by DFT and TD-DFT calculations which highlight the important role played by a ligand-to-metal charge-transfer states in directing the system towards either intersystem crossing to the triplet hypersurface or coordinative expansion to a five-coordinate quasi-stable intermediate. The latter processes occurs when the porphyrin is photolyzed in the presence of suitably located Lewis bases. Femtosecond time resolved absorbance measurements on Cu(II)-5,10,15,20-meso-tetrakis(N-methylpyridium-4-yl)porphyrin confirm that the coordinative expansion in water occurs in approximately 700 fs while crossing to the triplet hypersurface takes approximately 140 fs in the same solvent. These processes are mutually exclusive, but both can occur simultaneously depending on the environment of the porphyrin. The ratio of the two processes depends on the relative orientation of the Lewis base with respect to the copper atom at the time of excitation. As a consequence, copper porphyrins such as these, are excellent probes to the environment of the porphyrin, and can be used to identify the location of the porphyrin when interacting with DNA fragments.

The increasing popularity of porphyrins and hydroporphyrins for application in a variety of biomedical (photodynamic therapy, fluorescence tagging and imaging, photoacoustic imaging) and technical (chemosensing, catalysis, light harvesting) applications is also associated with the growing number of methodologies that enable their solubilization in aqueous media. Natively, the vast majority of synthetic porphyrinic compounds are not water-soluble. Moreover, any water-solubility imposes several restrictions on the synthetic chemist on when to install solubilizing groups in the synthetic sequence, and how to isolate and purify these compounds. This review summarizes the chemical modifications to render synthetic porphyrins water-soluble, with a focus on the work since 2000. Where available, practical data such as solubility, indicators for the degree of aggregation, and special notes for the practicioner are listed. We hope that this review will guide synthetic chemists through the many strategies known to make porphyrins and hydroporphyrins water soluble.

Treatment regimens are regularly evolving, together with novel therapies and drugs. Such evolution is necessary to circumvent resistance mechanisms and to give patients the best possible health care. When dealing with cancer, most regimens involve multiple treatments (surgery, radiation therapy, chemotherapy, immunotherapy, etc.). The purpose of this study was to associate in a single compound metal-based drugs and photosensitizers to combine chemotherapy and photodynamic therapy. Two arene-ruthenium tetrapyridylporphyrin compounds (2H-TPyP-arene-Ru and Zn-TPyP-arene-Ru) have been synthesized and evaluated on two colorectal cancer cell lines (HCT116 and HT-29). The cytotoxicity and phototoxicity have been evaluated. In addition, the anticancer mechanism and the cell death process mediated by the two compounds were studied. The results showed that the two arene-ruthenium photosensitizer-containing complexes have a strong phototoxic effect after photoactivation. The 2H-TPyP-arene-Ru induced outstanding cytotoxicity when compared to the Zn-TPyP-arene-Ru analogue. Moreover, under light, these two arene-ruthenium photosensitizers induce an apoptotic process in human colorectal cancer cell lines.

Two gallium porphyrins, a tetraphenyl GaCl porphyrin, termed as (TPP)GaCl, and an octaethylporphyrin GaCl porphyrin, termed as (OEP)GaCl were synthesized to use as electron cascade in ternary organic bulk heterojunction films. A perfect matching of both gallium porphyrins energy levels with that of poly(3-hexylthiophene-2,5-diyl) (P3HT) or poly[N-9′-heptadecanyl-2,7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)] (PCDTBT) polymer donor and the 6,6-phenyl C71 butyric acid methyl ester (PCBM) fullerene acceptor forming an efficient cascade system that could facilitate electron transfer between donor and acceptor was demonstrated. Therefore, ternary organic solar cells (OSCs) using the two porphyrins in various concentration were fabricated, where a performance enhancement was obtained. In particular, (TPP)GaCl-based ternary OSCs of low concentration (1:0.05 vv%) exhibited a ~17 % increase of the power conversion efficiency (PCE) compared with the binary device due to improved exciton dissociation, electron transport and reduced recombination. On the other hand, ternary OSCs with the (TPP)GaCl of high concentration (1:0.1 vv%) and (OEP)GaCl (1:0.05 and 1:0.1 vv%) showed poorest efficiencies due to very rough nanomorphology and suppressed crystallinity of ternary films when the GaCl porphyrin introduced in the blend, as revealed from X-ray diffraction (XRD) and atomic force microscopy (AFM). The best performed devices exhibited also improved photostability, when exposed to sunlight illumination for a period of 8 h than the binary OSCs, attributed to the suppressed photodegradation of the ternary (TPP)GaCl 1:0.05-based photoactive film.

Different therapeutic strategies have been investigated to target and eliminate HIV-1-infected cells by using armed antibodies specific to viral proteins, with varying degrees of success. Herein, we propose a new strategy by combining photodynamic therapy (PDT) with HIV Env-targeted immunotherapy, and refer to it as HIV photoimmunotherapy (PIT). A human anti-gp41 antibody (7B2) was conjugated to two photosensitizers with different charges through different linking strategies; “Click” conjugation by using an azide-bearing porphyrin attached via a disulfide bridge linker with a drug-to-antibody ratio (DAR) of exactly 4, and “Lysine” conjugation by using phthalocyanine IRDye 700DX dye with average DARs of 2.1, 3.0 and 4.4. These photo-immunoconjugates (PICs) were compared via biochemical and immunological characterizations regarding the dosimetry, solubility, and cell targeting. Photo-induced cytotoxicity of the PICs were compared using assays for apoptosis, reactive oxygen species (ROS), photo-cytotoxicity, and confocal microscopy. Targeted phototoxicity seems to be primarily dependent on the binding of PS-antibody to the HIV antigen on the cell membrane, whilst being independent of the PS type. This is the first report of the application of PIT for HIV immunotherapy by killing HIV Env-expressing cells.

The metalloporphyrin heme acts as the oxygen-complexing prosthetic group of hemoglobin in blood. Heme has been noted to survive for many millions of years in fossils. Here we investigate its stability and degra-dation under various conditions expected to occur during fossilization. Oxidative, reductive, aerobic, and anaerobic conditions were studied at neutral and alkaline pH values. Elevated temperatures were applied to accelerate degradation. High-performance liquid chromatography coupled to tandem mass spectrome-try (HPLC-MS/MS) identified four main degradation products. The vinyl residues are oxidized to formyl and further to carboxylate groups. In the presence of air or H2O2, cleavage of the tetrapyrrole ring occurs, and hematinic acid is formed. The highest stability of heme was observed under anaerobic reductive condi-tions (half-life 9.5 days), while the lowest stability was found in the presence of H2O2 (half-life 1 min). We confirmed that the iron cation plays a crucial role in degradation, since protoporphyrin IX, lacking iron, re-mained significantly more stable. Under anaerobic, reductive conditions, the above-mentioned degradation products were not observed, suggesting a different degradation pathway. To our knowledge, this is the first molecular taphonomy study on heme, which will be useful for understanding its fate during fossiliza-tion.

: The article examines the regularities of structure formation of ultrafine fibers based on poly-3-hydroxybutyrat under the influence of technological (electrical conductivity, viscosity), molecular (molecular weight), and external factors (low-molecular and nanodispersed substances of different chemical nature). Systems with polar substances are characterized by the presence of intermolecular interactions and the formation of a more perfect crystalline fiber structure. Changes in technological and molecular characteristics affect the fiber formation process, resulting in alterations in the morphology of the non-woven fabric, fiber geometry, and supramolecular fiber structure. Polymer molecular weight, electrical conductivity, and solution viscosity influence fiber formation and fiber diameter. The fiber structure is heterogeneous, consisting of both crystalline and non-equilibrium amorphous phases. This is significant in the development of matrix-fibrillar systems for drug delivery, bioactive substances, antiseptics, tissue engineering constructs, tissue engineering scaffolds, artificial biodegradable implants, sorbents, and other applications.

Manganese porphyrins reportedly exhibit synergic effects when combined with irradiation. However, an in-depth understanding of intratumoral heterogeneity and immune pathways, as affected by Mn porphyrins, remains limited. Here, we explored the mechanisms underlying immunomodulation of a clinical candidate, MnTnBuOE-2-PyP5+ (BMX-001, MnBuOE), using single-cell analysis in murine carcinoma model. Mice bearing 4T1 tumors were divided into 4 groups: control, MnBuOE, radiotherapy (RT), combined MnBuOE and radiotherapy (MnBuOE/RT). In epithelial cells, epithelial-mesenchymal transition, TNF-α signaling via NF-кB, angiogenesis, and hypoxia-related genes were significantly downregulated in the MnBuOE/RT compared to the RT. All subtypes of cancer-associated fibroblasts (CAFs) were clearly reduced in MnBuOE and MnBuOE/RT. Inhibitory receptor-ligand interactions, in which epithelial cells and CAFs interacted with CD8+ T cells, were significantly lower in the MnBuOE/RT than in the RT. Trajectory analysis showed that DC maturation-associated markers were increased in MnBuOE/RT. M1 macrophages were significantly increased in the MnBuOE/RT compared to the RT, whereas myeloid-derived suppressor cells were decreased. CellChat analysis showed that the number of cell-cell communications was the lowest in the MnBuOE/RT. Our study is the first to provide evidence for the combined radiotherapy with a novel Mn porphyrin clinical candidate, BMX-001 from the perspective of each cell-type within the tumor microenvironment.