Photodynamic therapy and nuclear imaging activities of SubPhthalocyanine integrated TiO2 nanoparticles

Recent advances in subphthalocyanines and related subporphyrinoids

Subporphyrinoids constitute a class of extremely versatile and attractive compounds. Herein, a comprehensive review of the most recent advances in the fundamentals and applications of these cone-shaped aromatic macrocycles is presented.

Nanoparticle-Mediated Delivery Systems in Photodynamic Therapy of Colorectal Cancer

Colorectal cancer (CRC) involving a malignant tumour remains one of the greatest contributing causes of fatal mortality and has become the third globally ranked malignancy in terms of cancer-associated deaths. Conventional CRC treatment approaches such as surgery, radiation, and chemotherapy are the most utilized approaches to treat this disease. However, they are limited by low selectivity and systemic toxicity, so they cannot completely eradicate this disease. Photodynamic therapy (PDT) is an emerging therapeutic modality that exerts selective cytotoxicity to cancerous cells through the activation of photosensitizers (PSs) under light irradiation to produce cytotoxic reactive oxygen species (ROS), which then cause cancer cell death. Cumulative research findings have highlighted the significant role of traditional PDT in CRC treatment; however, the therapeutic efficacy of the classical PDT strategy is restricted due to skin photosensitivity, poor cancerous tissue specificity, and limited penetration of light. The application of nanoparticles in PDT can mitigate some of these shortcomings and enhance the targeting ability of PS in order to effectively use PDT against CRC as well as to reduce systemic side effects. Although 2D culture models are widely used in cancer research, they have some limitations. Therefore, 3D models in CRC PDT, particularly multicellular tumour spheroids (MCTS), have attracted researchers. This review summarizes several photosensitizers that are currently used in CRC PDT and gives an overview of recent advances in nanoparticle application for enhanced CRC PDT. In addition, the progress of 3D-model applications in CRC PDT is discussed.

Synthesis of axially disubstituted silicon phthalocyanines and investigation of their in vitro cytotoxic/phototoxic anticancer activities

In this study, two SiPcs have been selected and the photodynamic therapy potentials were evaluated of the Pcs. Synthesis of Axially 2-decyn-1-oxy disubstituted Es-SiPc-2 was newly synthesized by the reaction of SiPcCl2 with 2-decyn-1-ol in the presence of NaH in toluene. Furthermore, their nuclear imaging potentials were evaluated in human colon adenocarcinoma (HT-29) and human lung fibroblast cell (WI-38) cell lines. The uptake results have indicated that Es-SiPc labeled with [Formula: see text]I radionuclide ([Formula: see text]I-Es-SiPc) was approximately 2-fold higher in the HT-29 cell line than the WI-38 cell line. In other words, the target/non-target tissue ratio is defined as two in the HT-29/WI-38 cell lines. Besides, the uptake values of [Formula: see text]I-Es-SiPc were found to be higher than [Formula: see text]I-Es-SiPc-2. [Formula: see text]I-Es-SiPc and [Formula: see text]I-Es-SiPc-2 are promising for imaging or treating colon adenocarcinoma. In vitrophotodynamic therapy (PDT) studies have shown that both compounds are suitable and can be used in this field. Also, Es-SiPc has been shown to have higher phototoxicity than Es-SiPc-2.

Antifungal photodynamic activities of phthalocyanine derivatives on Candida albicans

Antimicrobial resistance is one of the most important causes of morbidity and mortality in the treatment of infectious diseases worldwide. Candida albicans is one of the most virulent and common species of fungi to cause invasive fungal infections on humans. Alternative treatment strategies, including photodynamic therapy, are needed for controlling these infectious diseases. The aim of this study was to investigate the antifungal photodynamic activities of phthalocyanine derivatives on C. albicans. The minimum inhibitory concentration (MIC) values of compounds were determined by the broth microdilution method. Uptake of the compounds in C. albicans and dark toxicity of the compounds were also investigated. Photodynamic inhibition of growth experiments was performed by measuring the colony-forming unit/mL (CFU/mL) of the strain. Maximum uptake into the cells was observed in the presence of 64 μg/mL concentration for each compound except for ZnPc. Compounds did not show dark toxicity/inhibitory effects at sub-MIC concentrations on C. albicans when compared to the negative control groups. Zn(II)Pc, ZnPc, and ZnPc-TiO₂ showed fungicidal effect after irradiation with the light dose of 90 J/cm² in the presence of the compounds. In addition to the fungicidal effects, SubPc, SubPc-TiO₂, Es-SiPc, and Es-SubPc compounds were also found to have inhibitory effects on the growth of yeast cells after irradiation.

Differential Immunomodulatory Activities of Schiff Base Complexes Depending on their Metal Conjugation

Immunomodulatory compounds have become crucial with advances in immunotherapy. Using our own immune system cells, we can direct the immune cell function and develop desired response against a certain threat. Immunotherapy applications have been suggested against tumors, autoimmune disorders, and infectious diseases. Vaccination can be considered as one of the best known example of immunotherapy. Infectious agent's signature molecular structures are introduced to the immune cells together with the adjuvants that further activate the immune cells to mount a proper immune response and memory. Immunotherapy and vaccine formulations are in constant need of a library of immunomodulatory reagents that can be applied depending on the target. In order to expand the number of immunomodulatory reagents that can find medicinal applications, our group has been testing unique chemical structures on the immune system cells, especially macrophages. Schiff base complexes are known for their anti-inflammatory and antimicrobial activities. In this study, we used previously characterized Schiff base complexes with different metal conjugations. These molecules had differential immunostimulatory and immunomodulatory potentials on macrophages in vitro depending on the type of the conjugated metal. After light exposure, these complexes changed their characteristics and became powerful anti-inflammatory complexes. Due to their possible antimicrobial potentials, we also tested their activities against gram negative and gram positive bacteria. All of the complexes exerted antimicrobial activities which were not light responsive. Here, we present Schiff base complexes with differential immunostimulatory and immunomodulatory activities that can also efficiently eliminate gram positive and gram negative bacteria. Upon photo activation, they block the production of inflammatory TNFα cytokine. Therefore, together with the light, they can be used to treat bacterial infections associated with damaging inflammation. Graphical Abstract.

Novel BODIPY-subphthalocyanine dyads with reasonable photodynamic therapy behaviours

In this study, a set of bio-compatible and NIR emissive BODIPY-subphthalocyanine dyads (SP–DBD1–3) that contain amphiphilic triethyleneglycol units supporting partial water solubility and red absorbing BODIPY monomers (DBD1–3) were prepared.

Evaluation of photodynamic therapy and nuclear imaging potential of subphthalocyanine integrated TiO2 nanoparticles in mammary and cervical tumor cells

This study, subphthalocyanines (SubPc) and SubPc integrated TiO2 nanoparticles (SubPc-TiO[Formula: see text] were synthesized as novel photosensitizers. Their PDT effects were evaluated. Furthermore, nuclear imaging potential of [Formula: see text]I-labelled SubPc/SubPc-TiO2 were examined in mouse mammary carcinoma (EMT6) and cervix adenocarcinoma (HeLa) cell lines. The uptake results show that SubPc labelled with [Formula: see text]I radionuclide ([Formula: see text]I-SubPc) in EMT6 and HeLa cell lines was found to be approximately the same as in the WI38 cell line. However, the uptake values of SubPc-TiO2 labelled with [Formula: see text]I ([Formula: see text]I-SubPc-TiO[Formula: see text] in EMT6 and HeLa cell lines were determined to be two times higher than in the WI38 cell line. In other words, the target/non-target tissue ratio was identified as two in the EMT6 and HeLa cell lines. [Formula: see text]I-SubPc-TiO2 is promising for imaging or treatment of breast and cervix tumors. In vitro photodynamic therapy studies have shown that SubPc and SubPc-TiO2 are suitable agents for PDT. In addition, SubPc-TiO2 has higher phototoxicity than SubPc. As a future study, in vivo experiments will be held and performed in tumor-bearing nude mice.

Polymer Capsules for Enzymatic Catalysis in Confined Environments

Catalysis is at the base of a series of biological and technological application processes. In recent years, the tendency has developed to carry out catalyzed reactions within confined structures, thus forming systems called micro or nanoreactors. Compartmentalized structures are cavities delimited by a wall where specific functions are introduced with a defined concentration and in the desired sites. These containers are generally referred to as nano or microcapsules, assuming the function of reactors in the presence of chemical reactions. Among the various types of existing structures, one of the most interesting is represented by systems made with polymers. This review aims to highlight some of the current advances in the use of functionalized structures that are useful for catalysis reactions, paying particular attention to polymer capsules and enzymes. The built-up methods used for the production of polymer capsules, as well as the aspects that influence membrane permeability and reactivity to environmental conditions, are discussed. Recent advances on biocatalysis confined in polymeric capsules are illustrated, and the strengths and weaknesses of the principal nanoreactors are considered.

Antibacterial properties of subphthalocyanine and subphthalocyanine-TiO2 nanoparticles on Staphylococcus aureus and Escherichia coli

Nowadays the problem of antimicrobial resistance is the most important cause of morbidity and mortality in the treatment of infectious diseases worldwide. Treatment options for antimicrobial-resistant microorganisms are quite limited. Therefore, alternative treatment strategies are needed to control infectious diseases. Antimicrobial photodynamic therapy (aPDT) is one of the new treatment modalities proposed for a wide variety of infections. In the basic principle of aPDT, photosensitizers (PS) produce free radicals by irradiating them with harmless light at the appropriate wavelength, and this causes microorganism cell cytotoxicity.

In this study, light emitting diodes (LED) (630–700 nm, 17.4 mW/cm[Formula: see text] were used on Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli) at different light doses under the minimum inhibitory concentration (MIC) values of SubPc and SubPc-integrated TiO2 nanoparticles (SubPc-TiO[Formula: see text] concentration. Both compounds show good phototoxicity toward S. aureus when high light doses (16, 24[Formula: see text]J/cm[Formula: see text] were applied. In addition, SubPc-TiO2 were found to be more effective than SubPc in aPDT of S. aureus. In E. coli, the success of aPDT has been shown to be dependent on the increased light dose (20, 30[Formula: see text]J/cm[Formula: see text] for both compounds. As a result, the aPDT activity of SubPc-TiO2 is more effective than SubPc in increasing light doses.