Synthesis, characterization and in vitro photodynamic antimicrobial activity of basic amino acid-porphyrin conjugates

Engineering a protein-based nanoplatform as an antibacterial agent for light activated dual-modal photothermal and photodynamic therapy of infection in both the NIR I and II windows

Ultra-small protein-based nanoparticles with absorption in both the NIR I and II biological windows were designed as new photoactivatable antibacterial agents.

Porphyrinoid biohybrid materials as an emerging toolbox for biomedical light management

The present article reviews the most important developing strategies in light-induced nanomedicine, based on the combination of porphyrinoid photosensitizers with a wide variety of biomolecules and biomolecular assemblies.

Synthesis and bioactivities study of new antibacterial peptide mimics: The dialkyl cationic amphiphiles

The emergence of infectious diseases caused by pathogenic bacteria is widespread. Therefore, it is urgently required to enhance the development of novel antimicrobial agents with high antibacterial activity and low cytotoxicity. A series of novel dialkyl cationic amphiphiles bearing two identical length lipophilic alkyl chains and one non-peptidic amide bond were synthesized and tested for antimicrobial activities against both Gram-positive and Gram-negative bacteria. Particular compounds synthesized showed excellent antibacterial activity toward drug-sensitive bacteria such as S. aureus, E. faecalis, E. coli and S. enterica, and clinical isolates of drug-resistant species such as methicillin-resistant S. aureus (MRSA), KPC-producing and NDM-1-producing carbapenem-resistant Enterobacteriaceae (CRE). For example, the MIC values of the best compound 4g ranged from 0.5 to 2 μg/mL against all these strains. Moreover, these small molecules acted rapidly as bactericidal agents, and functioned primarily by permeabilization and depolarization of bacterial membranes. Importantly, these compounds were difficult to induce bacterial resistance and can potentially combat drug-resistant bacteria. Thus, these compounds can be developed into a new class of antibacterial peptide mimics against Gram-positive and Gram-negative bacteria, including drug-resistant bacterial strains.

Water-soluble Manganese and Iron Mesotetrakis(carboxyl)porphyrin: DNA Binding, Oxidative Cleavage, and Cytotoxic Activities

Two new water-soluble metal carboxyl porphyrins, manganese (III) meso-tetrakis (carboxyl) porphyrin and iron (III) meso-tetrakis (carboxyl) porphyrin, were synthesized and characterized. Their interactions with ct-DNA were investigated by UV-Vis titration, fluorescence spectra, viscosity measurement and CD spectra. The results showed they can strongly bind to ct-DNA via outside binding mode. Electrophoresis experiments revealed that both complexes can cleave pBR322 DNA efficiently in the presence of hydrogen peroxide, albeit 2-Mn exhibited a little higher efficiency. The inhibitor tests suggest the oxidative DNA cleavage by these two complexes may involve hydroxyl radical active intermediates. Notably, 2-Mn exhibited considerable photocytotoxicity against Hep G2 cell via triggering a significant generation of ROS and causing disruption of MMP after irradiation.

Photodynamic antimicrobial chemotherapy with the novel amino acid-porphyrin conjugate 4I: In vitro and in vivo studies

Photodynamic antimicrobial chemotherapy (PACT), as a novel and effective therapeutic modality to eradicate drug resistant bacteria without provoking multidrug resistance, has attracted increasing attention. This study examined the antimicrobial efficacy of the novel cationic amino acid-porphyrin conjugate 4I with four lysine groups against two different clinical isolated strains (drug sensitive and multidrug resistant) of the Acinetobacter baumannii species and its toxicity on murine dermal fibroblasts in vitro, as well as the therapeutic effect of PACT on acute, potentially lethal multidrug resistant strain excisional wound infections in vivo. The PACT protocol exposed 4I to illumination, exhibiting high antimicrobial efficacy on two different strains due to a high yield of reactive oxygen species (ROS) and non-selectivity to microorganisms. The photoinactivation effects of 4I against two different strains were dose-dependent. At 3.9 μM and 7.8 μM, PACT induced 6 log units of inactivation of sensitive and multidrug resistant strains. In contrast, 4I alone and illumination alone treatments had no visibly antimicrobial effect. Moreover, cytotoxicity tests revealed the great safety of the photosensitizer 4I in mice. In the in vivo study, we found 4I-mediated PACT was not only able to kill bacteria but also accelerated wound recovery. Compared with non-treated mice, over 2.89 log reduction of multidrug resistant Acinetobacter baumannii strain was reached in PACT treat mice at 24 h post-treatment. These results imply that 4I-mediated PACT therapy is an effective and safe alternative to conventional antibiotic therapy and has clinical potential for superficial drug-resistant bacterial infections.

Synthesis, characterisation and catalytic use of iron porphyrin amino ester conjugates

This study described the synthesis and characterisation of C₂-symmetrical chiral Fe(iii)(porphyrin)(OMe) complexes, whose activity as cyclopropanation catalysts was investigated from both experimental and theoretical viewpoints.

Influence of N atom number and form on the photodynamic activities of zinc phthalocyanines

Amino group modified phthalocyanines (Pcs) and their derivatives have attracted great attention in the field of photodynamic therapy (PDT) because of their satisfied anticancer activity. The existence of N atoms in these Pcs is very important because they not only provide water solubility of Pcs, but also greatly affect their PDT activity. To clear the influence of N atoms number on PDT activity of amino group modified Pcs and their derivatives, in this manuscript, two series of amine modified Pcs with different N atom number and their water soluble derivatives, hydrochloride and quaternizing derivatives were synthesized. Their photochemical and photobiology properties were studied and compared. The results indicated that with increasing the number on N atom, the reactive oxygen species (ROSs) generation ability, cancer cell uptaken ability and photoinduced anticancer activity were all increased in these ZnPcs.

Photodegradation of organic pollutants in water by immobilized porphyrins and phthalocyanines

New methods for water treatment are required as a result from an increasing awareness in the reduction of the pollution impact in the environment. In the perspective of the photo-oxidation of organic pollutants present in water, the principal incentive for the preparation of heterogeneous photocatalysts is their easy recovery from the reaction mixture, which allows their reuse in successive runs, minimizing the loss of their original photocatalytic properties. Different types of supports can be used in the immobilization of photoactive species, such as porphyrins (Pors) and phthalocyanines (Pcs). This mini-review will consider the different methodologies for the immobilization of Pors and Pcs and their photocatalytic performance in the photodegradation of organic pollutants in water, addressing also their recycling ability in successive water treatments.

Mechanism and In Vivo Evaluation: Photodynamic Antibacterial Chemotherapy of Lysine-Porphyrin Conjugate

Lysine-porphyrin conjugate 4i has potent photosensitive antibacterial effect on clinical isolated bacterial strains such as Methicillin-resistant Staphylococcus aureus (MRSA), Escherichia coli, and Pseudomonas aeruginosa. The mechanism of photodynamic antibacterial chemotherapy of 4i (4i-PACT) in vitro and the treatment effect in vivo was investigated in this paper. Atomic force microscopy (AFM) revealed that 4i-PACT can effectively destroy membrane and wall of bacteria, resulting in leakage of its content. This was confirmed by dual fluorescent staining with acridine orange/ethidium bromide and measuring materials absorption at 260 nm. Agarose gel electrophoresis measurement showed that 4i-PACT can damage genomic DNA. Healing of wound in rat infected by mixed bacteria showed that the efficiency of 4i-PACT is dependent on the dose of light. These results showed that 4i-PACT has promising bactericidal effect both in vitro and in vivo.

A purpurin-peptide derivative for selective killing of Gram-positive bacteria via insertion into cell membrane

A purpurin-peptide derivative was used for discriminating and killing bacteria based on the different surface components of bacteria.