The photodynamic antimicrobial chemotherapy of Stapphylococcus aureus using an asymmetrical zinc phthalocyanine conjugated to silver and iron oxide based nanoparticles

The application of Sn(IV)Cl2 and In(III)Cl porphyrin-dyed TiO2 nanofibers in photodynamic antimicrobial chemotherapy for bacterial inactivation in water

The World Health Organization has reported that antimicrobial resistance is one of the top 10 health threats that humanity faces today. Due to this, alternative therapies to the common antimicrobials are being explored and among these is photodynamic antimicrobial chemotherapy, where a combination of light, a photosensitizer and reactive oxygen species can be used to target microbial cells. In this research, free base, tin (IV) and indium (III) tetramethoxyporphyrins photosensitizers are adsorbed onto inorganic titanium dioxide nanofibers in an effort to create reusable fibers that are effective against Staphylococcus aureus. The photodynamic antimicrobial chemotherapy studies indicate that the metalloporphyrin adsorbed nanofibers exhibit good photodynamic antimicrobial activity against Staphylococcus aureus where the Cl2Sn(IV) tetramethoxyporphyrin dyed TiO2 exhibited 100% bacterial inhibition after a 30 min irradiation period.

Fluorinated Phthalocyanine/Silver Nanoconjugates for Multifunctional Biological Applications

In this study, a new phthalonitrile derivative namely 4-[(2,4-difluorophenyl)ethynyl]phthalonitrile (1) and its metal phthalocyanines (2 and 3) were synthesized. The resultant compounds were conjugated to silver nanoparticles and characterized using transmission electron microscopy (TEM) images. The biological properties of compounds (1-3), their nanoconjugates (4-6), and silver nanoparticles (7) were examined for the first time in this study. The antioxidant activities of biological candidates (1-7) were studied by applying the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. The highest antioxidant activity was obtained 97.47 % for 200 mg/L manganese phthalocyanine-silver nanoconjugates (6). The antimicrobial and antimicrobial photodynamic therapy (APDT) activities of biological candidates (1-7) were examined using a micro-dilution assay. The highest MIC value was obtained 8 mg/L for nanoconjugate 6 against E. hirae. The studied compounds and their silver nanoconjugates exhibited high APDT activities against all the studied microorganisms. The most effective APDT activities were obtained 4 mg/L for nanoconjugates (5 and 6) against L. pneumophila and E. hirae, respectively. All the studied biological candidates displayed high cell viability inhibition activities against E. coli cell growth. The biofilm inhibition activities of the tested biological candidates were also investigated against S. aureus and P. Aeruginosa. Biological candidates (1-6) can be considered efficient metal nanoparticle-based materials for multi-disciplinary biological applications.

Controlled Self-Assembly of Low-Dimensional Supramolecular Systems Based on Double-Decker Lanthanide Phthalocyaninates

Abstract

Possessing unique physicochemical properties, phthalocyanines are widely used as active components of supramolecular ensembles and nanomaterials. The functional properties of phthalocyanine-based materials are governed by not only the structure of their discotic molecules, but also the character of their intermolecular interactions, which determine both the self-assembly mechanism and the structure of such systems. This review discusses the experimental approaches, which are based on the notions of colloid and coordination chemistry that enable one to control intermolecular interactions in low-dimensional supramolecular ensembles based on phthalocyanines and metallocomplexes thereof. Using double-decker crown-substituted lanthanide phthalocyaninates as an example, it is shown how one- and two-dimensional nanomaterials with different properties can be obtained from the same type of building blocks employing a set of colloid-chemical methods. Such materials are, in particular, capable for controlled absorption of visible light in ultrathin films and can be employed as conducting one-dimensional components of planar elements for organic electronics.

New phthalonitrile/metal phthalocyanines-gold nanoparticle conjugates for biological applications

The appearance of nanoscience and its effect on the development of the scientific fields particularly materials chemistry have been well-known today. In this study, a new di-substituted phthalonitrile derivative namely...

Antimicrobial Photodynamic Therapy: Latest Developments with a Focus on Combinatory Strategies

Antimicrobial photodynamic therapy (aPDT) has become a fundamental tool in modern therapeutics, notably due to the expanding versatility of photosensitizers (PSs) and the numerous possibilities to combine aPDT with other antimicrobial treatments to combat localized infections. After revisiting the basic principles of aPDT, this review first highlights the current state of the art of curative or preventive aPDT applications with relevant clinical trials. In addition, the most recent developments in photochemistry and photophysics as well as advanced carrier systems in the context of aPDT are provided, with a focus on the latest generations of efficient and versatile PSs and the progress towards hybrid-multicomponent systems. In particular, deeper insight into combinatory aPDT approaches is afforded, involving non-radiative or other light-based modalities. Selected aPDT perspectives are outlined, pointing out new strategies to target and treat microorganisms. Finally, the review works out the evolution of the conceptually simple PDT methodology towards a much more sophisticated, integrated, and innovative technology as an important element of potent antimicrobial strategies.

The improved antibacterial efficiency of a zinc phthalocyanine when embedded on silver nanoparticle modified silica nanofibers

This work reports on the fabrication and modification of electrospun polymer free silica nanofibers (SiO₂ NFs) with the aim of creating heterogeneous antibacterial catalysts. The optical and photophysical properties of the obtained NFs i.e. bare SiO₂, Ag-SiO₂, Pc-SiO₂ and Pc@Ag-SiO₂ NFs (Pc = phthalocyanine) were compared and reported. The singlet oxygen quantum yields of the Pc-SiO₂ and Pc@Ag-SiO₂ NFs were also quantified and found to be 0.08 and 0.12, respectively, in water. All the modified SiO₂ NFs were found to possess photoactivity against S. aureus with the most effective being the Pc@Ag-SiO₂ NFs due to the synergy between the Pc and Ag nanoparticles. The bare SiO₂ NFs do not exhibit any antibacterial activity while the Ag-SiO₂ and Pc@Ag-SiO₂ NFs were found to also exhibit dark toxicity. The generated photocatalysts are attractive because they are active against bacteria and they are easily retrievable post-application. The nanocatalysts reported herein are therefore feasible candidates for real-life antibacterial applications.

A career in photophysicochemical and electrochemical properties of phthalocyanine — a Linstead Career Award paper

This manuscript highlights the author’s contributions to phthalocyanine chemistry, especially the applications based on their electrochemistry and photophysicochemistry. In particular, the use of phthalocyanines as electrocatalysts and photocatalysts is presented. For photocatalysis, photodynamic antimicrobial chemotherapy and pollution control using green technologies are highlighted. For electrocatalysis the phthalocyanines are employed for the detection of pollutants and environmentally important molecules. Phthalocyanines are combined with nanomaterials for improved photocatalysis and electrocatalysis.