Quantum Yield Of Generation Research Articles

Photosensitized Generation of Singlet Oxygen (1O2) from Pyropheophorbide a Specifically Bound to All Parallel-Stranded G-Quadruplex DNAs.

Pyropheophorbide a (Pyro-a), a chlorophyll metabolite, is a potential photosensitizer for photodynamic therapy (PDT), but little is known about its interaction with the target molecules for PDT, e.g., nucleic acids. Elucidation of the interaction between photosensitizers and nucleic acids will help us understand the initial process of PDT at the molecular level and hence to develop photosensitizing agents. We found that pyro-a forms a 1:1 complex with an all parallel-stranded G-quadruplex DNA and that pyro-a in the complex exhibits a quantum yield for singlet oxygen generation, with excitation at 664 nm, higher by a factor of ∼10 than that of pyro-a in an aqueous solution. These findings provided novel insights into molecular design of pyro-a-based photosensitizers to enhance their PDT efficacy.

Novel fluorescent mono-Br-BODIPYs as potential theranostic agents and their nanoscale zeolitic imidazolate framework delivery systems

The development of bifunctional theranostic agents based on biocompatible organic luminophores is a priority for the scientific community. We have obtained new mono-Br-substituted BODIPYs (Br-BDPs) with an optimal combination of fluorescence quantum yield (0.48 ÷ 0.63) and singlet oxygen generation quantum yield (0.32 ÷ 0.51) in different nature solvents. A detailed analysis of the structure of α-Br-BDP, β-Br-BDP, and β'-Br-BDP dyes, their spectral properties depending on the position of the bromine atom attachment and the solvent nature, as well as the aggregation behavior of the dyes in water/THF solvent mixture are presented. We also selected the conditions for the host–guest encapsulation of β-Br-BDP in zeolitic imidazolate framework (ZIF-8). The resulting nanoscale β-Br-BDP@ZIF-8 delivery systems exhibit intense fluorescence. The release of the β-Br-BDP luminophore from the β-Br-BDP@ZIF-8 systems into model lipid structures in phosphate buffer pH 5.0 – 6.0 occurs on average after 24 – 50 h. These results form the basis for the further development of new theranostic drugs based on Br-BDP luminophores for fluorescence diagnostics (FD) and photodynamic therapy (PDT).

Design rules for oxoporphyrinogen (‘OxP’) as a versatile chromophore for efficient singlet oxygen generation

Meso-5,10,15,20-tetrakis-3,5-di-tert-butyl-4-oxocyclohexadienylideneporphyrinogen, OxP, is a versatile, highly colored chromophore with strong broad absorption in the visible range. It is derived from meso-5,10,15,20-tetrakis(3,5-di-tert-butyl-4-hydroxyphenyl)porphyrin by two-electron oxidation, and the OxP tetrapyrrole moiety exists in a saddle conformation. N-Alkylation of the OxP core nitrogen atoms can be used to functionalize the chromophore leading to a class of stable molecules with highly substituted peripheries. Substituted OxPs can act as singlet oxygen generators under light irradiation and the efficacy of this process is influenced by the multiplicity of N-substitution, and by the chemical identity of those substituents. Bromination of the macrocyclic [Formula: see text]-positions can also be used to control singlet oxygen generation by the relevant derivatives. We report the quantum yields of singlet oxygen generation for a series of differently substituted OxP derivatives whose metrics indicate that these compounds possess significant potential in the corresponding applications including photodynamic therapy, bacterial inactivation therapy, and organic transformations.

Strategies to develop α-aminoketone derivatives photoinitiators with low migration ability for UV–vis LED photopolymerization

In this work, a polymerizable vinyl sulfide modified 907 derivative (PI-1) and four macromolecular photoinitiators (PI-2–5) based on PI-1 were designed and synthesized to realize low migration together with a high photoactivity. The structures of these photoinitiators were confirmed by 1H NMR, 13C NMR, HRMS, and GPC analysis. Time-resolved 1H NMR, photolysis, and quantum yield experiments illustrated that the rate of the photogenerated free radicals from PI-1 was slower than that of Irgacure 907. The macromolecular strategies of PI-1 successfully improved the photoactivity of PI-2–5 compared with PI-1. Moreover, PI-4 prepared by copolymerization between PI-1 and methyl methacrylate demonstrated a higher quantum yield of free radical generation than Irgacure 907 and better photoinitiating performance as evaluated by bulk and solution photopolymerization. Furthermore, the migration stabilities of these photoinitiators in the photocured films were better than those of 907. The high efficiency and low migration of the above photoinitiators make them potential applications in food packaging and biological materials.

Photochemical Processes of Superbase Generation in Xanthone Carboxylic Salts

AbstractPhotobase generators are species that allow the photocatalysis of various reactions, such as thiol‐Michael, thiol‐isocyanate, and ring‐opening polymerization reactions. However, existing compounds have complex syntheses and low quantum yields. To overcome these problems, photobase generators based on the photodecarboxylation reaction were developed. We synthesized and studied the photochemistry and photophysics of two xanthone photobase, their carboxylic acid precursors, and their photoproducts to understand the photobase generation mechanism. We determined accurate quantum yields of triplet states and photobase generation. The effect of the intermediate radical preceding the base release was demonstrated. We characterized the photophysics of the photobase by femtosecond spectroscopy and showed that the photodecarboxylation process occurred from the second excited triplet state with a rate constant of 2.2×109 s−1.

Photochemical Processes of Superbase Generation in Xanthone Carboxylic Salts.

Photobase generators are species that allow the photocatalysis of various reactions, such as thiol-Michael, thiol-isocyanate, and ring-opening polymerization reactions. However, existing compounds have complex syntheses and low quantum yields. To overcome these problems, photobase generators based on the photodecarboxylation reaction were developed. We synthesized and studied the photochemistry and photophysics of two xanthone photobase, their carboxylic acid precursors, and their photoproducts to understand the photobase generation mechanism. We determined accurate quantum yields of triplet states and photobase generation. The effect of the intermediate radical preceding the base release was demonstrated. We characterized the photophysics of the photobase by femtosecond spectroscopy and showed that the photodecarboxylation process occurred from the second excited triplet state with a rate constant of 2.2×109 s-1 .

Antibody-guided iodinated cyanine for near-IR photoimmunotherapy

Photoimmunotherapy (PIT) is a cancer treatment modality that synergistically combines immunotherapy and photodynamic treatment (PDT). Many current photosensitizers used in PDT and PIT applications such as porphyrins suffer from insufficient light absorption in the near-IR spectra region, which reduces their phototoxicity. Cyanine dyes exhibit much more pronounced absorption in the near-IR region but they are less explored for PDT and their antibody-guided conjugates have not yet been studied for PIT applications. In this work, for the first time a “cyanine dye — antibody” PIT conjugate is developed and studied. We synthesized novel, highly water soluble, near-IR, diiodinated heptamethine cyanine dye, 2ICy7, conjugated this dye with the breast cancer-specific monoclonal antibody trastuzumab, and investigated the obtained PIT conjugate in the mouse xenograft model to suppress tumor growth versus the parent, non-iodinated Cy7–Ab conjugate. The quantum yields of the singlet oxygen generation in aqueous media for the iodinated 2ICy7 dye and 2ICy7–Ab conjugate were found to be about 3-fold higher compared to the non-iodinated counterparts, Cy7 and Cy7–Ab. As a result, the 2ICy7–Ab conjugate suppressed tumor growth upon PIT four-fold more efficiently than Cy7–Ab, while the immunotherapeutic effect resulted only in 1.4-fold suppression.

Development of a quantitative structure-activity relationship model for predicting quantum yield of hydroxyl radical generation from organic compounds.

Organic compounds are capable of generating hydroxyl radicals (˙OH) through their excited triplet states in natural water. It is of significance to reveal the underlying mechanism of the generation and obtain the generation quantum yield of ˙OH from organic compounds for better understanding of its involvement in indirect photochemical processes in the environment. In this study, the ˙OH quantum yields (Φ˙OH) of 20 organic compounds were determined by photochemical experiments. The calculated Φ˙OH values for the selected organic compounds vary from (1.2 ± 0.39) × 10-5 to (7.2 ± 0.16) × 10-4. A quantitative structure-activity relationship (QSAR) model for log Φ˙OH was developed and the established model was proven to have a proper goodness of fit, robustness, and predictive ability. The QSAR model was successfully used to predict the Φ˙OH value of organic pollutants. Mechanistic interpretation showed that the electron distribution and the electronegativity of organic compounds are the most important factors that determine the generation of ˙OH. The results are helpful for understanding the generation mechanism of ˙OH from organic compounds and also provide insights into the generation of ˙OH from dissolved organic matter in natural water.

Medium viscosity effect on the fluorescent properties of arrays consisting of two BODIPY chromophores axially bound to a Sn(IV)porphyrin via a phenolate bridge

The arrays consisting of two BODIPY chromophores axially bound to a Sn(IV)Porphyrin via a phenolate bridge have been synthesized and characterized. Photophysical properties of obtained systems have been investigated in aqua medium with different viscosity due to the addition of glycerin. The fluorescence quantum yield of the triad upon excitation at different wavelengths, as well as its lifetime and singlet oxygen generation quantum yield in an excited state, has been determined. It has been shown that if in the triad composition the fluorescent properties of the BODIPY fragment are weakened in all studied media, then the fluorescent properties of the porphyrin fragment depend on the properties of the medium. Quenching of the BODIPY fluorescence and the porphyrin fluorescence enhancement in viscous media or increasing of the triad’s ability to generate singlet oxygen in water is the result of photo-induced electron transfer from the phenolate to the porphyrin fragment. The efficiency of electron transfer and, consequently, the efficiency of quenching depend on the conformational mobility of the ligandin the triad, i.e. on the relative position of the phenolic and indacene fragments, which gives the designed triad the properties of a fluorescent molecular rotor. The best efficiency of the triad as a fluorescence molecular rotor has been obtained in the low viscosity range from 1 to 4 cP.

Spectroscopic Investigations of Porphyrin-TiO2 Nanoparticles Complexes

This study presents the spectral characterization of TiO2 nanoparticles (NPs) functionalized with three porphyrin derivatives: 5,10,15,20-(Tetra-4-aminophenyl) porphyrin (TAPP), 5,10,15,20-(Tetra-4-methoxyphenyl) porphyrin (TMPP), and 5,10,15,20-(Tetra-4-carboxyphenyl) porphyrin (TCPP). UV-Vis absorption and Fourier transform infrared spectroscopy-attenuated total reflection (FTIR-ATR) spectroscopic studies of these porphyrins and their complexes with TiO2 NPs were performed. In addition, the efficiency of singlet oxygen generation, the key species in photodynamic therapy, was investigated. UV-Vis absorption spectra of the NPs complexes showed the characteristic bands of porphyrins. These allowed us to determine the loaded porphyrins on TiO2 NPs functionalized with porphyrins. FTIR-ATR revealed the formation of porphyrin-TiO2 complexes, suggesting that porphyrin adsorption on TiO2 may involve the pyrroles in the porphyrin ring, or the radicals of the porphyrin derivative. The quantum yield for singlet oxygen generation by the studied porphyrin complexes with TiO2 was higher compared to bare porphyrins for TAPP and TMPP, while for the TCPP-TiO2 NPs complex, a decrease was observed, but still maintained a good efficiency. The TiO2 NPs conjugates can be promising candidates to be tested in photodynamic therapy in vitro assays.

All-in-one phototheranostics based on BTP-4F-DMO nanoparticles for NIR-II fluorescence/photoacoustic dual-mode imaging and combinational therapy

Various phototheranostics have recently been developed for phototherapy. Through proper molecular design, the photochemical and photophysical properties of these phototheranostics can be promoted. Herein, an acceptor-donor-acceptor (A-D-A)-structured dye, BTP-4F-DMO, was synthesized and prepared into water-soluble nanoparticles (NPs). The obtained BTP-4F-DMO NPs had strong absorption from 650 nm to 850 nm and a fluorescence emission peak at ∼900 nm that tailed to ∼1100 nm. The NPs showed a superhigh photothermal conversion efficiency of 90.5% ± 5% and could simultaneously generate •OH and 1O2 with a 1O2 generation quantum yield of 4.6% under 808 nm laser irradiation. Due to these advanced properties, BTP-4F-DMO NPs can switch the role of autophagy from pro-survival to pro-death, thereby further promoting cancer cell death. These features make BTP-4F-DMO NPs a promising multifunctional phototheranostic agent for NIR-II fluorescence/photoacoustic dual-mode imaging-guided synergetic photodynamic/photothermal therapy. In general, this work provides a strategy for expanding the biomedical applications of organic A-D-A-structured phototheranostics.

Robust route toward cationic phthalocyanines through reductive amination

New synthetic pathway toward water-soluble phthalocyanines (Pc) bearing cationic 4-(N,N,N-trialkylammonium-methyl)-phenoxy groups has been elaborated. It involves the convenient reductive amination of various (4-formylphenoxy)-substituted phthalonitriles with diethylamine and NaBH(OAc)3, leading to 3-, 4- and 4,5-(p-diethylaminomethyl-phenoxy)-substituted phthalonitriles as precursors to new Zn(II), Mg(II) and metal-free phthalocyanines (4α-MPc, 4β-MPc and 8β-MPc, M = 2H, Mg, Zn) containing four or eight cationic groups in non-peripheral (α-) or peripheral (β-) positions. Novel compounds have been characterized by different spectroscopic techniques (1H, 13C NMR, FTIR, UV–Vis) and MALDI TOF mass spectrometry. All cationic Pcs exhibited strong absorption in the phototherapeutical spectral range from 670 to 700 nm (εmax > 105 M−1cm−1) and high quantum yields of singlet oxygen generation in DMSO where all phthalocyanines existed in monomeric forms. Also, cationic complexes showed moderate solubility in water with high tendency to aggregation, however α-substituted Zn(II) and Mg(II) complexes existed in water in predominantly monomeric states. Further monomerization of Zn(II) complex 4α-ZnPc in aqueous solution can be achieved by interaction either with non-ionic surfactant Tween-80 or bovine serum albumin (BSA). The advantage of our results is not limited to new convenient synthetic approach to the cationic phthalocyanines but it also consists in preparation of new phototherapeutic agents with promising photophysical and photochemical properties.

Primary photoprocesses for Fe(III) complexes with citric and glycolic acids in aqueous solutions

The mechanism of UV photolysis of Fe(III) complexes with citric ([FeCit] and [Fe(OH)Cit]−) and glycolic ([FeGlyc]+) acids was revealed. The excitation of the complexes leads to the predominant formation of corresponding long-lived radical complexes exhibiting a low-intensity absorption band in the visible region (λmax = 600, 550 and 660 nm for ([FeCit], [Fe(OH)Cit]− and [FeGlyc]+ complexes, accordingly). The primary quantum yields of photolysis at 355 nm are 0.17, 0.28 and 0.12 for these complexes, accordingly. The decomposition of radical complexes leads to the appearance of corresponding organic radicals in solution, which are further oxidized in competitive processes by the initial complexes and dissolved oxygen. This enhances quantum yields of generation of ferrous ions in steady-state conditions and can also lead to a good yield of hydroxyl radicals in subsequent Fenton-like reactions in the presence of dissolved oxygen. The further study of the efficiency of OH radical generation upon excitation of these systems are urgently needed in order to estimate their role in environmental aqueous chemistry and to assess their potential use in advanced oxidation processes.

Zinc(II), Palladium(II), and Metal-Free Phthalocyanines Bearing Nipagin-Functionalized Substituents against Candida auris and Selected Multidrug-Resistant Microbes.

Due to the rapidly increasing problem of antibiotic resistance in recent years, the use of phthalocyanines as photosensitizers with their superior properties in photodynamic antimicrobial therapy (PACT) applications has become important. In this study, magnesium(II) 1,4,8,11,15,18,22,25-octakis(4-[4-butoxycarbonylphenoxy]butyloxy)phthalocyanine was used in the demetalation reaction in trifluoroacetic acid, and subsequently subjected to metalation reaction in dimethylformamide with zinc(II) acetate and bis(benzonitrile)palladium(II) chloride towards zinc(II) and palladium(II) derivatives. Three phthalocyanines, including a demetalated one as well as two metalated, in the core with zinc(II) and palladium(II) were characterized using 1D and 2D NMR spectroscopy and mass spectrometry. In addition, all macrocycles were subjected to absorption and emission studies as well as photostability tests. In a photochemical study, zinc(II) and palladium(II) phthalocyanine complexes appeared to be efficient singlet oxygen generators. There were noted quantum yields of singlet oxygen generation for zinc(II) phthalocyanine derivative in DMF and DMSO at 0.55 and 0.72, whereas for palladium(II) complex at 0.73 and 0.77, respectively. Liposomal formulations of phthalocyanine derivatives were prepared, and their activity was evaluated against a broad spectrum of antibiotic-resistant microorganisms, such as methicillin-resistant Staphylococcus aureus (MRSA), Escherichia coli (ESBL+), Candida albicans resistant to fluconazole, C. auris, and against dermatophytes. Phthalocyanine palladium(II) complex showed the highest bactericidal activity against all antibiotic-resistant microorganisms, including reducing C. auris growth at 3.54 log.

Study of acute toxicity of monocationic chlorin e6 derivative, a perspective photosensitizer for antimicrobial and antitumor photodynamic therapy

In this experimental work the acute toxicity of a chemically modified derivative of the natural pigment chlorophyll a called monocationic chlorin e6, which is a promising photosensitizer (PS) for antimicrobial and antitumor photodynamic therapy, was studied using white rats. The advantages of the PS under investigation are an intense absorption in the long-wavelength region of the visible spectrum, a sufficiently high quantum yield of singlet oxygen generation, pronounced amphiphilic properties along with an appropriate solubility in water, and a high level of photocytotoxic- ity in relation to both malignant HeLa cells and antibiotic-resistant hospital strains of E. сoli bacteria., P. aerugenosa and others. It has been shown that the value of LD 50 of the considered PS can be calculated as the value of 100 mg/kg. In the reproduced experimental model of acute toxicity, pathomorphological changes in the vital organs of laboratory animals indicate a pronounced vasopathic effect of the drug with the development of cerebral edema and respiratory distress syndrome, which have become the main signs of thanatogenesis.

Metal or metal-free phthalocyanines containing morpholine substituents: synthesis, spectroscopic and photophysicochemical properties

The phthalonitrile (3) and its peripherally tetra 4-(3-morpholinophenoxy) substituted metal-free (4), lead(II) (5) and zinc(II) (6) phthalocyanine derivatives were synthesized. The structures of 3-6 were confirmed by FT-IR, 1H-NMR, MALDI-TOF mass, UV-vis and fluorescence spectral data. The solubility and aggregation behaviors of 4-6 were determined in dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), tetrahydrofuran (THF), chloroform (CHCl3) and dichloromethane (CH2Cl2). The observed sharp absorptions were evidence of formation of non-aggregated phthalocyanine species at the studied concentration. The effects of the substituent and central metal ions (metal-free, zinc or lead) on spectroscopic and photophysicochemical properties were determined. Their photophysicochemical properties such as fluorescence quantum yields and lifetimes, singlet oxygen generation and photodegradation quantum yields were investigated in DMSO. The fluorescence spectra of metal-free (4) and lead(II) (5) phthalocyanines were not recorded due to negligible fluorescence emissions of these phthalocyanines. The zinc(II) phthalocyanine (6) had 0.17 fluorescence quantum yield (ΦF) and 1.42 fluorescence lifetime (τF). The phthalocyanines (4-6) had 0.18, 0.41, 0.52 singlet oxygen quantum yields (ΦΔ) and 0.51, 3.90, 0.46 photodegradation quantum yields (ΦΔ), respectively. The zinc(II) phthalocyanine (6) in particular could be a potential Type II photosensitizer candidate for photodynamic therapy in cancer treatment.

(Invited) Probing Charge Carrier Dynamics in Porphyrin-Based Bulk Heterojunction Thin Films with Time-Resolved Terahertz Spectroscopy

Organic photovoltaic (OPV) solar cells have attracted much attention in recent years because of the low production cost and ease of device fabrication. However, the power conversion efficiency is still low compared to the silicon and perovskite solar cells so that further research is necessary to improve their performance. In particular, understanding of the detailed mechanisms of charge carrier generation, recombination and carrier transport process is very important for developing design principles of new compounds for OPVs. Until now, polymer-based compounds have been widely used for p-type semiconductors. However, it is not easy to obtain information on how the microscopic structure of bulk heterojunction (BHJ) blend of donor and acceptor materials affect the charge carrier dynamics because one cannot easily control the molecular weight and conformational distributions of polymer compounds. On the other hand, small molecule-based semiconductors have several unique advantages such well-defined chemical structures, ease of purification and small batch-to-batch variations.Tetrabenzoporphyrin (BP) has been frequently used as a small-molecule organic semiconductor. Recently, Yamada and coworkers synthesized diketopyrrolopyrrole-linked tetrabenzoporphyrin (DPP-BP) conjugates that have linear alkyl groups on the DPP moieties whose chain length is defined as n, namely, Cn-DPP-BP (n=4, 6, 8, or 10). For DPP-BP based solar cells, they demonstrated that alkyl chain length affects the power conversion efficiency. Therefore, it is very interesting to see how the local BHJ structures of DPP-BP based thin films affect the initial step of the charge carrier dynamics because such studies are difficult to perform for polymer-based systems. We can take advantage of small molecule-based systems to study the relationship between the local structure and the charge carrier dynamics.In this work, we used time-resolved terahertz (THz) spectroscopy to investigate the charge carrier dynamics of DPP-BP BHJ thin films blended with [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM). Time-resolved THz spectroscopy is a unique method to quantify charge carrier mobility with very fast time resolution (less than picosecond). This spectroscopy reflects the charge carrier dynamics in the local spatial region because of the high-frequency nature of the THz electric field. We chose C4-DPP-BP:PC61BM and C10-DPP-BP:PC61BM thin films for the THz measurements. In the previous study, it was found that C4-DPP-BP molecule prefers to take a face-on geometry on the substrate. A grain size of the aggregates was around 100 nm or smaller which were measured by atomic force microscopy. In such a structure, one can expect that charge transport takes place very efficiently to the electrode. Actually, power conversion efficiency is 5.2 % which is highest among a series of DPP-BP chromophores. On the other hand, C10-DPP-BP adopts an edge-on geometry on the substrate and forms micrometer-sized aggregates. In this structure, molecular stacking is oriented perpendicular to the electrode so that power conversion efficiency decreases to 0.19%.In contrast to the other measurements, the THz spectroscopy has sensitivity to in-plane motion of the charge carriers with respect to the substrate, we expect to observe higher in-plane mobility of the charge carriers in the C10-DPP-BP:PC61BM BHJ films compared to C4-DPP-BP based films. In contrast to our intuitive expectation, we found that the product of the carrier mobility and the yield of the photo-generated charge carriers is similar to each other. We consider that the similarity of the charge carrier dynamics results from the high-frequency nature of the local mobility of the polarons because most of the polarons are confined in less than a 10-nm length scale. Furthermore, the lowest limit of the carrier mobility obtained from our results is about 1.0 cm2V-1s-1 when the quantum yield of the charge carrier generation is assumed to be unity. This value is much higher than those obtained by space-charge-limited current method. We expect that charge separation occurs very efficiently when the local mobility of the charge carrier is high.In this contribution, we will present importance of the local mobility of the charge carriers and difference of charge transport between short and long length scales in DPP-BP based solar cells.

Zinc(II) Sulfanyltribenzoporphyrazines with Bulky Peripheral Substituents—Synthesis, Photophysical Characterization, and Potential Photocytotoxicity

The study’s aim was to synthesize new unsymmetrical sulfanyl zinc(II) porphyrazines and subject them to physicochemical and electrochemical characterization and also an initial acute toxicity assessment. The procedure was initiated from a commercially available dimercaptomaleonitrile disodium salt and o-phthalonitrile using Linstead’s macrocyclization reaction conditions, which led to magnesium(II) tribenzoporphyrazine with 4-(3,5-dibutoxycarbonylphenoxy)butylthio substituents. The obtained macrocycle was demetallated with trifluoroacetic acid and subsequently remetallated with zinc(II) acetate toward the zinc(II) porphyrazine derivative. The zinc(II) tribenzoporphyrazine with 4-(3,5-dibutoxycarbonylphenoxy)butylthio substituents was then subjected to the reduction reaction with LiAlH4, yielding zinc(II) tribenzoporphyrazine with 4-[3,5-di(hydroxymethyl)phenoxy]butylthio substituents. The new zinc(II) tribenzoporphyrazines were characterized by UV-Vis spectroscopy, various NMR techniques (1HNMR, 13CNMR, 1H-1H COSY, 1H-13C HSQC, and 1H-13C HMBC), and mass spectrometry. In the UV-Vis spectra, both macrocycles revealed characteristic Soret and Q-bands, whose positions were dependent on the solvent used for the measurements. Zinc(II) tribenzoporphyrazines were studied using electrochemical and photochemical methods, including the singlet oxygen generation assessment. Both zinc(II) porphyrazines revealed high singlet oxygen generation quantum yield values of up to 0.59 in DMSO, which indicates their potential photosensitizing potential for photodynamic therapy. In addition, new derivatives were subjected to a Microtox® bioluminescence assay.

A “donor–acceptor” structured semiconductor polymer for near infrared fluorescence imaging guided photodynamic therapy

Near infrared (NIR) fluorescence imaging guided photodynamic therapy (PDT) is a technique which has been developed in many clinical trials due to its advantage of real-time optical monitoring, specific spatiotemporal selectivity, and minimal invasiveness. For this, photosensitizers with NIR fluorescence emission and high 1O2 generation quantum yield are highly desirable. Herein, we designed and synthesized a “donor–acceptor” (D-A) structured semiconductor polymer (SP), which was then wrapped with an amphiphilic compound (Pluronic[Formula: see text] F127) to prepare water-soluble nanoparticles (F-SP NPs). The obtained F-SP NPs exhibit good water solubility, excellent particle size stability, strong absorbance at deep red region, and strong NIR fluorescent emission characteristics. The maximal mass extinction coefficient and fluorescence quantum yield of these F-SPs were calculated to be 21.7 L/(g[Formula: see text]cm) and 6.5%, respectively. Moreover, the 1O2 quantum yield of 89% for F-SP NPs has been achieved under 635 nm laser irradiation, which is higher than Methylene Blue, Ce6, and PpIX. The outstanding properties of these F-SP NPs originate from their unique D-A molecular characteristic. This work should help guide the design of novel semiconductor polymer for NIR fluorescent imaging guided PDT applications.

Comparison of the Photodynamic Effect of Two Chlorins, Photodithazine and Fotoenticine, in Gliosarcoma Cells

The treatment and prognosis of cancers of the nervous system remain unfavorable to the patient, which makes it necessary to study alternative therapies as primary or adjuvant treatments to existing methods. Photodynamic Therapy (PDT) is a method that consists of combining a photosensitizer (PS), a light source at the appropriate wavelength, and molecular oxygen, forming reactive oxygen species (ROS), leading to death in the target cell. The objective of this work was to compare the effects of PDT with two chlorins, Photodithazine (PDZ) and Fotoenticine (FTC), in 9L/lacZ gliosarcoma cell lines. Both chlorins, together with an LED device at 660 nm with a fluence of 10 J/cm², were included in the study. It was observed that the response to therapy depends on the concentration and type of PS used. In addition, PDZ showed a higher quantum yield of singlet oxygen generation than FTC.