Photosensitizing effects and physicochemical properties of chlorophyll a derivatives with hydrophilic oligoethylene glycol fragments at the macrocycle periphery

In this work, screening studies of the cytotoxic effect of chlorins with fragments of di-, tri-, and pentaethylene glycol at the macrocycle periphery in relation to HeLa, A549, and HT29 cells were performed. It is shown that, despite different hydrophobicity, all the compounds studied have a comparable photodynamic effect. The conjugate of chlorin e6 with pentaethylene glycol, which has the lowest tendency to association among the studied compounds with tropism for low density lipoproteins and the best characteristics of the formation of molecular complexes with Tween 80, has a significant difference in dark and photoinduced toxicity (ratio IC50(dark)/IC50(photo) approximately 2 orders of magnitude for all cell lines), which allows to hope for a sufficiently large "therapeutic window". A study of the interaction of this compound with HeLa cells shows that the substance penetrates the cell and, after red light irradiation induces ROS appearance inside the cell, associated, apparently, with the photogeneration of singlet oxygen. These data indicate that photoinduced toxic effects are caused by damage to intracellular structures as a result of oxidative stress. Programmed type of cell death characterized with caspase-3 induction is prevailing. So, the conjugate of chlorin e6 with pentaethylene glycol is a promising antitumor PS that can be successfully solubilized with Tween 80, which makes it suitable for further in vivo studies.

Hydrophilic Biocompatible Fluorescent Organic Nanoparticles as Nanocarriers for Biosourced Photosensitizers for Photodynamic Therapy

Most photosensitizers of interest for photodynamic therapy-especially porphyrinoids and chlorins-are hydrophobic. To circumvent this difficulty, the use of nanocarriers is an attractive strategy. In this perspective, we have developed highly water-soluble and biocompatible fluorescent organic nanoparticles (FONPs) made from citric acid and diethyltriamine which are then activated by ethlynene diamine as nanoplatforms for efficient photosensitizers (PSs). Purpurin 18 (Pp18) was selected as a biosourced chlorin photosensitizer combining the efficient single oxygen generation ability and suitable absorption in the biological spectral window. The simple reaction of activated FONPs with Pp18, which contains a reactive anhydride ring, yielded nanoparticles containing both Pp18 and Cp6 derivatives. These functionalized nanoparticles combine solubility in water, high singlet oxygen generation quantum yield in aqueous media (0.72) and absorption both in the near UV region (FONPS) and in the visible region (Soret band approximately 420 nm as well as Q bands at 500 nm, 560 nm, 660 nm and 710 nm). The functionalized nanoparticles retain the blue fluorescence of FONPs when excited in the near UV region but also show deep-red or NIR fluorescence when excited in the visible absorption bands of the PSs (typically at 520 nm, 660 nm or 710 nm). Moreover, these nanoparticles behave as efficient photosensitizers inducing colorectal cancer cell (HCT116 and HT-29 cell lines) death upon illumination at 650 nm. Half maximal inhibitory concentration (IC50) values down to, respectively, 0.04 and 0.13 nmol/mL were observed showing the potential of FONPs[Cp6] for the PDT treatment of cancer. In conclusion, we have shown that these novel biocompatible nanoparticles, which can be elaborated from biosourced components, both show deep-red emission upon excitation in the red region and are able to produce singlet oxygen with high efficiency in aqueous environments. Moreover, they show high PDT efficiency on colorectal cancer cells upon excitation in the deep red region. As such, these functional organic nanoparticles hold promise both for PDT treatment and theranostics.

Glycosylated BODIPY- Incorporated Pt(II) Metallacycles for Targeted and Synergistic Chemo-Photodynamic Therapy

Pt(II)-BODIPY complexes combine the chemotherapeutic activity of Pt(II) with the photocytotoxicity of BODIPYs. Additional conjugation with targeting ligands can boost the uptake by cancer cells that overexpress the corresponding receptors. We describe two Pt(II) triangles, 1 and 2, built with pyridyl BODIPYs functionalized with glucose (3) or triethylene glycol methyl ether (4), respectively. Both 1 and 2 showed higher singlet oxygen quantum yields than 3 and 4, due to the enhanced singlet-to-triplet intersystem crossing. To evaluate the targeting effect of the glycosylated derivative, in vitro experiments were performed using glucose transporter 1 (GLUT1)-positive HT29 and A549 cancer cells, and noncancerous HEK293 cells as control. Both 1 and 2 showed higher cellular uptake than 3 and 4. Specifically, 1 was selective and highly cytotoxic toward HT29 and A549 cells. The synergistic chemo- and photodynamic behavior of the metallacycles was also confirmed. Notably, 1 exhibited superior efficacy toward the cisplatin-resistant R-HepG2 cells.

Recent Progress of Gold-Based Nanostructures towards Future Emblem of Photo-Triggered Cancer Theranostics: A Special Focus on Combinatorial Phototherapies

Cancer is one of the most dangerous health problems in the millennium and it is the third foremost human cause of death in the universe. Traditional cancer treatments face several disadvantages and cannot often afford adequate outcomes. It has been exhibited that the outcome of several therapies can be improved when associated with nanostructures. In addition, a modern tendency is being developed in cancer therapy to convert single-modal into multi-modal therapies with the help of existing various nanostructures. Among them, gold is the most successful nanostructure for biomedical applications due to its flexibility in preparation, stabilization, surface modifications, less cytotoxicity, and ease of bio-detection. In the past few decades, gold-based nanomaterials rule cancer treatment applications, currently, gold nanostructures were the leading nanomaterials for synergetic cancer therapies. In this review article, the synthesis, stabilization, and optical properties of gold nanostructures have been discussed. Then, the surface modifications and targeting mechanisms of gold nanomaterials will be described. Recent signs of progress in the application of gold nanomaterials for synergetic cancer therapies such as photodynamic and photo-thermal therapies in combination with other common interventions such as radiotherapy, chemotherapy, and will be reviewed. Also, a summary of the pharmacokinetics of gold nanostructures will be delivered. Finally, the challenges and outlooks of the gold nanostructures in the clinics for applications in cancer treatments are debated.

Ring-Fused meso-Tetraarylchlorins as Auspicious PDT Sensitizers: Synthesis, Structural Characterization, Photophysics, and Biological Evaluation

Novel 4,5,6,7-tetrahydropyrazolo[1,5-a]pyridine-fused meso-tetraarylchlorins, with different degrees of hydrophilicity (with methyl ester, hydroxymethyl, and carboxylic acid moieties), have been synthesized and their photophysical characterization as well as in vitro photocytotoxicity assessment against human melanoma and esophageal and bladder carcinomas was carried out. An integrated analysis of the photosensitizers’ performance, considering the singlet oxygen generation data, cell internalization, and intracellular localization, allowed to establish relevant structure-photoactivity relationships and the rationalization of the observed photocytotoxicity. In the diacid and monoalcohol series, chlorins derived from meso-tetraphenylporphyrin proved to be the most efficient photodynamic therapy agents, showing IC50 values of 68 and 344 nM against A375 cells, respectively. These compounds were less active against OE19 and HT1376 cells, the diacid chlorin with IC50 values still in the nano-molar range, whereas the monohydroxymethyl-chlorin showed significantly higher IC50 values. The lead di(hydroxymethyl)-substituted meso-tetraphenylchlorin confirmed its remarkable photoactivity with IC50 values below 75 nM against the studied cancer cell lines. Subcellular accumulation of this chlorin in the mitochondria, endoplasmic reticulum, and plasma membrane was demonstrated.

Ohmic heating-assisted synthesis and characterization of Zn(II), Cu(II) and Pd(II) complexes of heterocyclic-fused chlorins

Chlorins are highly interesting compounds due to their spectroscopic properties in both UV-Vis and NIR regions. Upon coordination to a metal ion, the corresponding metallochlorins exhibit more valuable physicochemical properties that enable a broader range of applications, such as in photodynamic therapy (PDT), water splitting catalysis, optical sensor devices and dye-sensitized solar cells. Synthetic chemistry has been in a continuous quest to fulfil most green chemistry requirements through the development of efficient reactions. Being a heating process that does not depend on heat transfer to the reaction medium, ohmic heating accomplishes the mentioned requirements and allows a fast and uniform heating regime thanks to the ionic conductivity of the reaction medium. Herein, we report the metallation of pyrrolidine- and isoxazolidine-fused chlorins with Zn(II), Cu(II) and Pd(II) salts by ohmic heating, using non-toxic aqueous solutions, and their corresponding physico-chemical characterization. All pyrrolidine-fused chlorins showed higher yields, when compared with isoxazolidine ones. From the thermogravimetric analysis performed it is possible to infer that the metal enhances the steadiness of the macrocycle, making it easier to cause the thermal decomposition of the pyrrolidine- and isoxazolidine-fused chlorins. The Zn(II) complexes showed high absorption in the NIR spectral region, a low fluorescence quantum yield and a short excited singlet state, which indicate the high efficiency of intersystem crossing to the triplet state, making them very promising candidates as photosensitizers for PDT.

Graphene quantum dots-porphyrins/phthalocyanines multifunctional hybrid systems: from interfacial dialogue to applications

Engineered well-ordered hybrid nanomaterials are at a symbolically pivotal point, just ahead of a long-anticipated human race transformation. Incorporating newer carbon nanomaterials like graphene quantum dots (GQDs) with tetrapyrrolic porphyrins...

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.

Application of TD-DFT Theory to Studying Porphyrinoid-Based Photosensitizers for Photodynamic Therapy: A Review

An important focus for innovation in photodynamic therapy (PDT) is theoretical investigations. They employ mostly methods based on Time-Dependent Density Functional Theory (TD-DFT) to study the photochemical properties of photosensitizers. In the current article we review the existing state-of-the-art TD-DFT methods (and beyond) which are employed to study the properties of porphyrinoid-based systems. The review is organized in such a way that each paragraph is devoted to a separate aspect of the PDT mechanism, e.g., correct prediction of the absorption spectra, determination of the singlet-triplet intersystem crossing, and interaction with molecular oxygen. Aspects of the calculation schemes are discussed, such as the choice of the most suitable functional and inclusion of a solvent. Finally, quantitative structure-activity relationship (QSAR) methods used to explore the photochemistry of porphyrinoid-based systems are discussed.

Advances in photosensitizer-related design for photodynamic therapy

Photodynamic therapy (PDT) is highly effective in treating tumors located near body surface, offering strong tumor suppression and low damage to normal tissue nearby. PDT is also effective for treating a number of other conditions. PDT not only provide a precise and selective method for the treatment of various diseases by itself, it can also be used in combination with other traditional therapies. Because PDT uses light as the unique targeting mechanism, it has simpler and more direct targeting capability than traditional therapies. The core material of a PDT system is the photosensitizer which converts light energy to therapeutic factors/substances. Different photosensitizers have their distinct characteristics, leading to different advantages and disadvantages. These could be enhanced or compensated by using proper PDT system. Therefore, the selected type of photosensitizer would heavily influence the overall design of a PDT system. In this article, we evaluated major types of inorganic and organic PDT photosensitizers, and discussed future research directions in the field.

Kinetics and mechanism of formation of nickel(II)porphyrin and its interaction with DNA in aqueous medium

Kinetics between 5,10,15,20-tetrakis(N-methylpyridium-4-yl)porphyrin and Ni²⁺ species were investigated in aqueous solution at 25 ±1 °C in I = 0.10 M (NaNO₃). Speciation of Ni²⁺ was done in I = 0.10 M (NaNO₃) for knowing distribution of Ni²⁺ species with solution pH. Experimental data were compared with speciation diagram constructed from the values of hydrolysis constants of Ni²⁺ ion. Speciation data showed that hexaaquanickel(II) ions took place in hydrolysis reactions through formation of [Ni(OH₂)_6-n(OH)_n]^2-n species with solution pH. According to speciation of Ni²⁺ and pH dependent rate constants, rate expression can be written as: d[Ni(TMPyP)⁴⁺]/dt = (k₁[Ni²⁺_(aq)] + k₂[Ni(OH)⁺_(aq)] + k₃[Ni(OH)₂^o_(aq)] + k₄[Ni(OH)₃^-_(aq)])[H₂TMPyP⁴⁺], where k₁, k₂, k₃ and k₄ were found to be k₁ = (0.62 ± 0.22) × 10^-2; k₂ = (3.60 ± 0.40) × 10^-2; k₃ = (2.09 ± 0.52) × 10^-2, k₄ = (0.53 ± 0.04) × 10^-2 M^-1s^-1 at 25 ±1 °C, respectively. Formation of hydrogen bonding between [Ni(H₂O)₅(OH)]⁺ and [H₂TMPyP]⁴⁺ causes enhanced reactivity. Rate of formation of [Ni(II)TMPyP]⁴⁺ complex was to be 3.99 × 10^-2 M^-1s^-1 in I = 0.10 M, NaNO₃ (25 ± 1 °C). UV-Vis and fluorescence data suggested that [Ni(II)TMPyP]⁴⁺ and [H₂(TMPyP)]⁴⁺ interact with DNA via outside binding with self-stacking and intercalation, respectively.

SYNOPSIS

Clinical Efficacy of HiPorfin Photodynamic Therapy for Advanced Obstructive Esophageal Cancer

Objective:

To explore the clinical efficacy of HiPorfin photodynamic therapy for advanced esophageal cancer and evaluate its impact on survival.

Methods:

Retrospective analysis of 32 patients with advanced obstructive esophageal cancer at our institution from September 2013 to December 2016. HiPorfin was infused as the photosensitizer at a dose of 5 mg/kg, and after 48 hours, 630-nm laser irradiation was subsequently performed through an optical fiber that passed through the biopsy channel of a flexible endoscope.

Results:

The effectiveness rate was 78.1% (25/32), and the significant efficacy rate was 56.3% (18/32). The dysphagia score decreased from 3.43 ± 0.73 to 1.79 ± 0.53 (P < .05). There was no grade 3 or more toxicity. The median overall survival was estimated to be 16 months. Univariate analysis showed higher overall survival with a Karnofsky Performance Status score ≥80 compared with a Karnofsky Performance Status score <80 (hazard ratio: 2.626; 95% CI: 1.091-6.322; P = .024). Overall survival was higher in patients who had received radiation therapy than in patients who did not receive radiation therapy (hazard ratio: 3.574; 95% CI: 1.501-8.510; P = .002).

Conclusion:

Photodynamic therapy is an effective method for advanced esophageal cancer. The side effects are mild, and the short-term effect is good, especially in the relief of dysphagia. Photodynamic therapy can prolong the survival of patients with advanced esophageal cancer, and the Karnofsky Performance Status score and previous radiation therapy have a significant effect on the overall survival.

In vitro phototoxicity of zinc phthalocyanine (ZnPc) loaded in liposomes against human breast cancer cells

In this study, zinc phthalocyanine (ZnPc) was encapsulated in liposomes (Phosphatidylcholine (PC) from soybean lecithin (95% phosphatidylcholine, 5% lysophosphatidylcholine), and phosphatidic acid) obtained by a reverse-phase evaporation method. Liposomes were characterized and cytotoxicity and phototoxicity assays were performed using mouse embryo fibroblast (NIH3T3) and human breast cancer (MDAMB231), respectively. ZnPc was successfully encapsulated in liposomes ([Formula: see text]80%), presenting single populations with sizes of [Formula: see text]300 nm and negative zeta potential (-35 to -40 mV). The release profile at different pH presented a biphasic release controlled by the Fickian diffusion mechanism. The cytotoxicity assays carried out on NIH3T3 cells showed that the liposomes provided good protection for ZnPc, and did not affect the viability of non-cancerous cells. In contrast, free ZnPc significantly reduced non-cancerous cell viability at higher concentrations. ZnPc loaded in liposomes ensured a higher phototoxic effect on the MDAMB231 cells at all concentrations tested when exposed to low light dose.

Novel chlorophyll a derivatives with ester-linked galactose fragments for photodynamic therapy and fluorescence diagnostics of cancer

In the present work, a number of chlorophyll [Formula: see text] derivatives were synthetized with galactose fragments with an ester bond between macrocycle and carbohydrate fragments. It showed that synthesized compounds fluoresce intensely inside HeLa cells, which enable these compounds to be considered as potential diagnostic agents and indicates their ability to remain in the cell in an unassociated photoactive state — a necessary condition for the realization of a photodynamic action. It was determined that while all conjugates had comparable photoinduced toxicities, the conjugate with phorbin macrocycle fragment had a much lower dark toxicity, which corresponds to the trends noted earlier. In terms of a therapeutic window, conjugate significantly exceeds similar derivatives of chlorin [Formula: see text] and is the most promising for further research.

Synthesis and ultrasound mediated antibacterial activity of ferrocene-triazole-porphyrin derivative

The [3 + 2]-cycloaddition reaction of various azides with ferrocenylmethylpropargyl ester in the presence of copper (I) salt lead to the formation of ferrocenyl-containing derivatives, including porphyrin, which exhibit pronounced cytotoxicity against Escherichia coli under ultrasound irradiation.

In vivo phototoxic effects of a tetraethyleneglycol-substituted Zn phthalocyanine in tumor bearing rats at an enzymatic level

TEG-Pc, a Zn(II) phthalocyanine tetra substituted in non-peripheral position by tetraethylene glycol chains, proved to have good efficiency during in vitro photodynamic experiments. Its in vivo phototoxic effects have been investigated in tumor-bearing Wistar albino rats at an enzymatic level. The evolution of different oxidative markers are reviewed 6 h after the treatment.

Combined pH-responsive chemotherapy and glutathione-triggered photosensitization to overcome drug-resistant hepatocellular carcinoma — a SPP/JPP Young Investigator Award paper

Doxorubicin (DOX) resistance, which results in a reduced accumulation of DOX in the nucleus and hence decreased DNA damage, is a major challenge for chemotherapy against hepatocellular carcinoma. In this paper, we combined chemotherapy with photodynamic therapy (PDT) to combat DOX-resistant human hepatocellular carcinoma cells. We have prepared the polymeric micelles conjugating with DOX and zinc(II) phthalocyanine (ZnPc) through a pH-responsive hydrazone linker and a glutathione (GSH)-responsive disulfide linker, respectively. The polymeric micelles (DOX-ZnPc-micelles) exhibited a spherical shape with a size of about 98 nm diameter and showed excellent stability in aqueous solution. Due to the self-quenching of the ZnPc inside the micelles, DOX-ZnPc-micelles did not emit fluorescence upon red light irradiation. Drug release experiments verified that DOX and ZnPc could be released under acidic conditions and reducing environments, respectively. A higher concentration of DOX was internalized into DOX-resistant R-HepG2 cells through the delivery of polymeric micelles when compared with the free DOX, hence DOX-ZnPc-micelles exhibited a significant enhancement in anticancer activity. The IC[Formula: see text] value of DOX against R-HepG2 cells was found to be 21 [Formula: see text]M when combined with PDT and it was 5-fold less than that of a single treatment of DOX (102 [Formula: see text]M). The DOX-ZnPc-micelles could induce cell apoptosis and necrosis on R-HepG2 cells by combined therapeutic modalities, while these micelles induced only apoptosis on HepG2 cells. We have demonstrated that utilization of polymeric micelles can significantly enhance the cellular uptake and cytotoxicity of DOX against R-HepG2 cells when compared with free DOX. Moreover, PDT can act as an adjuvant therapeutic modality and combine with chemotherapy to further improve therapeutic efficacy. Overall speaking, DOX-ZnPc-micelles can overcome DOX resistance and induce a synergistic therapeutic effect against DOX-resistant R-HepG2 cells, hence improving the therapeutic efficacy when compared with monotherapy.

Nanosystems of plant-based pigments and its relationship with oxidative stress

Plant-based pigments are widely present in nature, they are classified depending on their chemical structure as tetrapyrroles, carotenoids, polyphenolic compounds, and alkaloids and are extensively used in medicine, food industry, clothes, and others. Recently they have been investigated due to their role in the areas of food processing, food safety and quality, packaging, and nutrition. Many studies indicate a relationship between bioactive pigments and Non-Communicable Diseases derived from oxidative stress. Their biological applications can help in preventing oxidative injuries in the cell caused by oxygen and nitrogen reactive species. Those pigments are easily degraded by light, oxygen, temperature, pH conditions, among others. Nanotechnology offers the possibility to protect bioactive ingredients and increase its bioavailability after oral administration. Safety to humans (mainly evaluated from toxicity data) is the first concern for these products. In the present work, we present a comprehensive outlook of the most important plant-based pigments used as food colorants, the principal nanotechnology systems prepared with them, and the relationship of these compounds with the oxidative stress and related Non-Communicable Disease.

Octa-substituted metallophthalocyanines bearing (2,3-dihydrobenzo-1,4-benzodioxin-2-yl)methoxy and chloro groups: Synthesis, characterization and photophysicochemical studies

In this study, the synthesis and characterization of novel 4-chloro-5-((2,3-dihydrobenzo-1,4-benzodioxin-2-yl)methoxy)phthalonitrile (1) and its peripherally octa-substituted Zn(II) (Pc-Zn), In(III) (PcInCI) and Mg(II) (Pc-Mg) phthalocyanine (Pc) derivatives are reported for the first time. FT-IR, elemental analysis, UV-vis, NMR and MS techniques were used for characterization studies of the compounds. Aggregation properties of the compounds were evaluated in DMF, DMSO and THF solvents in different concentrations, and the compounds did not tend to aggregate in these solvents. In addition, photophysicochemical properties such as fluorescence, photodegradation and singlet oxygen quantum yield of the compounds were examined in DMSO, DMF and THF solvents to show the potential use of these novel compounds as photosensitizers for photodynamic therapy (PDT). The effects of zinc, indium and magnesium metals, octa substitutions in peripheral positions and different types of solvents on photophysicochemical properties were investigated. The singlet oxygen quantum yield values of compounds ranged from 0.27 to 0.77 in different solvents. As a result of the photophysicochemical properties, these compounds can be considered as potential candidates for PDT, applications.