Highlighting the Phototherapeutical Potential of Fungal Pigments in Various Fruiting Body Extracts with Informed Feature-Based Molecular Networking.

Fungal pigments are characterized by a diverse set of chemical backbones, some of which present photosensitizer-like structures. From the genus Cortinarius, for example, several biologically active photosensitizers have been identified leading to the hypothesis that photoactivity might be a more general phenomenon in the kingdom Fungi. This paper aims at testing the hypothesis. Forty-eight fruiting body-forming species producing pigments from all four major biosynthetic pathways (i.e., shikimate-chorismate, acetate-malonate, mevalonate, and nitrogen heterocycles) were selected and submitted to a workflow combining in vitro chemical and biological experiments with state-of-the-art metabolomics. Fungal extracts were profiled by high-resolution mass spectrometry and subsequently explored by spectral organization through feature-based molecular networking (FBMN), including advanced metabolite dereplication techniques. Additionally, the photochemical properties (i.e., light-dependent production of singlet oxygen), the phenolic content, and the (photo)cytotoxic activity of the extracts were studied. Different levels of photoactivity were found in species from all four metabolic groups, indicating that light-dependent effects are common among fungal pigments. In particular, extracts containing pigments from the acetate-malonate pathway, e.g., extracts from Bulgaria inquinans, Daldinia concentrica, and Cortinarius spp., were not only efficient producers of singlet oxygen but also exhibited photocytotoxicity against three different cancer cell lines. This study explores the distribution of photobiological traits in fruiting body forming fungi and highlights new sources for phototherapeutics.

Antiproliferative and Cytotoxic Activities of Fluorescein-A Diagnostic Angiography Dye.

Fluorescein is a fluorescent dye used as a diagnostic tool in various fields of medicine. Although fluorescein itself possesses low toxicity, after photoactivation, it releases potentially toxic molecules, such as singlet oxygen (1O2) and, as we demonstrate in this work, also carbon monoxide (CO). As both of these molecules can affect physiological processes, the main aim of this study was to explore the potential biological impacts of fluorescein photochemistry. In our in vitro study in a human hepatoblastoma HepG2 cell line, we explored the possible effects on cell viability, cellular energy metabolism, and the cell cycle. We observed markedly lowered cell viability (≈30%, 75-2400 µM) upon irradiation of intracellular fluorescein and proved that this decrease in viability was dependent on the cellular oxygen concentration. We also detected a significantly decreased concentration of Krebs cycle metabolites (lactate and citrate < 30%; 2-hydroxyglutarate and 2-oxoglutarate < 10%) as well as cell cycle arrest (decrease in the G2 phase of 18%). These observations suggest that this photochemical reaction could have important biological consequences and may account for some adverse reactions observed in fluorescein-treated patients. Additionally, the biological activities of both 1O2 and CO might have considerable therapeutic potential, particularly in the treatment of cancer.

A thermally activated delayed fluorescence photosensitizer for photodynamic therapy of oral squamous cell carcinoma under low laser intensity.

In this report, a new thermally activated delayed fluorescence (TADF) molecule [2-(4-triphenylvinyl-phenyl)-anthraquinone (TPE-AQ)] was synthesized. This nanomaterial has satisfactory photostability. Through In vitro analysis, it was found that these TADF nanoparticles (NPs) targeted lysosomes in oral cancer cells. ROS were released under irradiation with a 450-nm laser, and the growth of xenograft tumors in mouse models was inhibited in vivo. More interestingly, radiation exposure caused little damage to normal tissues due to the low irradiation intensity (mA) used in the photodynamic therapy (PDT) treatment of oral cancer. Therefore, these TADF NPs provide new possibilities for the development of new PDT drugs for biomedical applications. In future work, possible functional modifications of TADF NPs for increased potency in clinical applications will be addressed.

Chlorin e6-1,3-diphenylisobenzofuran polymer hybrid nanoparticles for singlet oxygen-detection photodynamic abaltion.

A dual-functional nanosysterm is developed by means of Chlorin e6 (Ce6) as photosensitizer and 1,3-Diphenylisobenzofuran (DPBF) as fluorescent singlet oxygen (1O2) probe. Under 660 nm laser irradiation, Ce6 exhibites efficient 1O2 generation, and subsequently the production of 1O2 is assessed by the ratiometric fluorescence of PFO and DPBF under one-photon and two-photon excitation mode. The nanoparticles with excellent biocompatibility can be internalized into Hela cells and applied for tumor treatment. For intracellular PDT, the nanoparticles perform a high phototoxicity, while the PDT proccess can be evaluated in time by monitoring fluorescence signals of DPBF. This theranostic nanosysterm provides a facile strategy to fabricate 1O2-detection PDT, which can realize accurate and efficient photodynamic therapy based on singlet oxygen detection.

Bioengineering a Light-Responsive Encapsulin Nanoreactor: A Potential Tool for In Vitro Photodynamic Therapy.

Encapsulins, a prokaryotic class of self-assembling protein nanocompartments, are being re-engineered to serve as "nanoreactors" for the augmentation or creation of key biochemical reactions. However, approaches that allow encapsulin nanoreactors to be functionally activated with spatial and temporal precision are lacking. We report the construction of a light-responsive encapsulin nanoreactor for "on demand" production of reactive oxygen species (ROS). Herein, encapsulins were loaded with the fluorescent flavoprotein mini-singlet oxygen generator (miniSOG), a biological photosensitizer that is activated by blue light to generate ROS, primarily singlet oxygen (1O2). We established that the nanocompartments stably encased miniSOG and in response to blue light were able to mediate the photoconversion of molecular oxygen into ROS. Using an in vitro model of lung cancer, we showed that ROS generated by the nanoreactor triggered photosensitized oxidation reactions which exerted a toxic effect on tumor cells, suggesting utility in photodynamic therapy. This encapsulin nanoreactor thus represents a platform for the light-controlled initiation and/or modulation of ROS-driven processes in biomedicine and biotechnology.

Effects of zinc porphyrin and zinc phthalocyanine derivatives in photodynamic anticancer therapy under different partial pressures of oxygen in vitro.

Photodynamic therapy (PDT) is gradually becoming an alternative method in the treatment of several diseases. Here, we investigated the role of oxygen in photodynamically treated cervical cancer cells (HeLa). The effect of PDT on HeLa cells was assessed by exposing cultured cells to disulphonated zinc phthalocyanine (ZnPcS2) and tetrasulphonated zinc tetraphenylporphyrin (ZnTPPS4). Fluorescence microscopy revealed their different localizations within the cells. ZnTPPS4 seems to be mostly limited to the cytosol and lysosomes, whereas ZnPcS2 is most likely predominantly attached to membrane structures, including plasmalemma and the mitochondrial membrane. Phototoxicity assays of PDT-treated cells carried out under different partial pressures of oxygen showed dose-dependent responses. Interestingly, ZnPcS2 was also photodynamically effective at a minimal level of oxygen, under a nitrogen atmosphere. On the other hand, hyperbaric oxygenation did not lead to a higher PDT efficiency of either photosensitizer. Although both photosensitizers can induce a significant drop in mitochondrial membrane potential, ZnPcS2 has a markedly higher effect on mitochondrial respiration that was completely blocked after two short light cycles. In conclusion, our observations suggest that PDT can be effective even in hypoxic conditions if a suitable sensitizer is chosen, such as ZnPcS2, which can inhibit mitochondrial respiration.

A General Method to Establish the Relative Efficiency of Different Sonosensitizers to Generate ROS for SDT.

The most common way to demonstrate the reactive oxygen species (ROS)-mediated pathways in photodynamic therapy (PDT) and in sonodynamic therapy (SDT) is the use of specific ROS inhibitors. We present a general method to establish the relative efficiency of different sonosensitizers which produce the same ROS. To demonstrate it, we use peroxides as sonosensitizers which produce singlet molecular oxygen. The method is easily generalized by all types of ROS.

Palladium porphyrin complexes for photodynamic cancer therapy: effect of porphyrin units and metal.

Photodynamic therapy (PDT) has been extensively explored for malignant tissue treatment. In this work, we successfully synthesized and characterized a series of porphyrin compounds by connecting porphyrin units with alkyl chains, which were then coordinated with palladium to yield related metal complexes, named Pd-Monopor, Pd-Dipor, and Pd-Tripor, respectively. The generation of reactive oxygen species (ROS) of six porphyrin compounds was investigated by the dichlorofluorescein (DCFH) method. As expected, the palladium porphyrin complexes showed the higher efficiency of ROS generation relative to free base porphyrins, probably due to the heavy atom effect. Remarkably, the efficiency of ROS generation increased with the number of porphyrin units in the photosensitizers. The order of ROS generation efficiency of the synthesized porphyrins was Pd-Tripor > Tripor > Dipor > Pd-Monopor > Pd-Dipor > Monopor. MTT assay suggested the good biocompatibility of the synthesized photosensitizers in the dark. Upon light irradiation, the palladium porphyrin complex exhibited higher therapeutic activity than free base porphyrin. The half-maximal inhibitory concentration (IC50) of Tripor and Pd-Tripor under light irradiation was calculated to be 18.2 and 9.6 µM, respectively. The cellular uptake and subcellular localization experiments indicated that Tripor was mainly localized in the lysosomes of cancer cells.

Carbon dot-assisted luminescence of singlet oxygen: the generation dynamics but not the cumulative amount of singlet oxygen is responsible for the photodynamic therapy efficacy.

A novel carbon dot-based luminescence probe for singlet oxygen (1O2) with a conventional optical detector has been implemented through the specific formation of electronically excited carbonyls from the breakdown of unstable endoperoxide intermediates, and its application in the real-time in vivo monitoring of 1O2 in photodynamic therapy (PDT) is achieved. More attractively, the relationship between the dynamics details of photosensitizer-generated 1O2 and the PDT efficacy has been established through a modified multiple-target survival model, enabling a direct and easy estimate of the surviving fraction of tumor cells from the generation dynamics of 1O2. Both in vitro and in vivo therapy results revealed that the rapid generation dynamics of 1O2 rather than its cumulative amount is responsible for better treatment efficacy in PDT. Overall, the deeper insight into the important roles of the generation dynamics of 1O2 in the PDT efficacy is irreplaceably advantageous in substantially reduced risks from deleterious treatment-related side effects by screening advanced photosensitizers and determining the light exposure end point.

Light-assisted gadofullerene nanoparticles disrupt tumor vasculatures for potent melanoma treatment.

The traditional photodynamic therapy (PDT) using a photosensitizer and oxygen under light generates reactive oxygen species (ROS) to kill tumor cells. However, its treatment efficiency is limited by insufficient oxygen in tumor cells. Herein, ß-alanine modified gadofullerene nanoparticles (GFNPs) were explored to disrupt tumor vasculatures assisted by light for potent melanoma treatment. As tumor vasculatures are oxygen-rich, the yields of photo-induced singlet oxygen (1O2) by GFNPs are not subjected to the hypoxemia of tumor tissues. Different from the small molecule photosensitizer Chlorin e6 (Ce6), GFNPs realize high-efficiency tumor vascular disruption under light observed by using the mice tumor vascular dorsal skin fold chamber (DSFC) model. The tumor vascular disruption efficiency of GFNPs is size-dependent, and the smallest one (hydration diameter of ca. 126 nm) is more efficient. Mechanistically, the high yields of photo-induced 1O2 by GFNPs can lead to the destruction of the tumor vascular endothelial adherent junction protein-VE cadherin and the decrease of tumor vascular endothelial cells-CD31 proteins, inducing rapid tumor necrosis. In conclusion, our work provides an insight into the design of well-sized nanoparticles to powerfully treat melanoma assisted by light, as well as greatly extending the applications of PDT for robust tumor therapy.

Post-synthesis strategy to integrate porphyrinic metal-organic frameworks with CuS NPs for synergistic enhanced photo-therapy.

Multifunctional nanotheranostic systems with both therapeutic and imaging functions are highly desired for the development of more effective and less toxic anti-tumor drugs. Herein, a simple but effective method is reported to fabricate a novel PCN-CuS-FA-ICG-based nanoplatform for dual-modal imaging-guided synergistic photothermal/photodynamic therapy. Porphyrinic metal-organic frameworks with CuS NPs are obtained in aqueous solution via a simple post-synthesis strategy. Furthermore, to obtain a more effective therapy, indocyanine green (ICG) was incorporated into the multifunctional theranostic platform to promote the photothermal therapeutic effect. The as-prepared PCN-CuS-FA-ICG not only exhibits an excellent 1O2 generation efficiency under 650 nm irradiation to achieve remarkable photodynamic cell killing, but also presents outstanding photothermal conversion under 808 nm irradiation to destroy tumor tissues by hyperthermia. In particular, the nanotherapeutic agent realized fluorescence and thermal imaging dual-modal imaging-guided cancer treatment. Meanwhile, in vivo experiments confirmed the evident accumulation of nanoparticles (NPs) at local tumors, and tumor growth was inhibited obviously via synergistic photothermal/photodynamic therapy with negligible side effects.

1O2 determined from the measured PDT dose and 3O2 predicts long-term response to Photofrin-mediated PDT.

Photodynamic therapy (PDT) that employs the photochemical interaction of light, photosensitizer and oxygen is an established modality for the treatment of cancer. However, dosimetry for PDT is becoming increasingly complex due to the heterogeneous photosensitizer uptake by the tumor, and complicated relationship between the tissue oxygenation ([3O2]), interstitial light distribution, photosensitizer photobleaching and PDT effect. As a result, experts argue that the failure to realize PDT's true potential is, at least partly due to the complexity of the dosimetry problem. In this study, we examine the efficacy of singlet oxygen explicit dosimetry (SOED) based on the measurements of the interstitial light fluence rate distribution, changes of [3O2] and photosensitizer concentration during Photofrin-mediated PDT to predict long-term control rates of radiation-induced fibrosarcoma tumors. We further show how variation in tissue [3O2] between animals induces variation in the treatment response for the same PDT protocol. PDT was performed with 5 mg kg-1 Photofrin (a drug-light interval of 24 h), in-air fluence rates (ϕ air) of 50 and 75 mW cm-2 and in-air fluences from 225 to 540 J cm-2. The tumor regrowth was tracked for 90 d after the treatment and Kaplan-Meier analyses for local control rate were performed based on a tumor volume ⩽100 mm3 for the two dosimetry quantities of PDT dose and SOED. Based on the results, SOED allowed for reduced subject variation and improved treatment evaluation as compared to the PDT dose.

Determination and analysis of singlet oxygen quantum yields of talaporfin sodium, protoporphyrin IX, and lipidated protoporphyrin IX using near-infrared luminescence spectroscopy.

In photodynamic therapy (PDT), singlet oxygen ([Formula: see text]) is the main species responsible for promoting tumor cell death. The determination of the quantum yield (ΦΔ) of a photosensitizer (PS) is important for dosimetry. The purpose of this paper is to quantify the [Formula: see text] generated by the PS by near-infrared spectroscopy (NIRS). The ΦΔ of different PS species were measured by the detection of near-infrared [Formula: see text] luminescence. From the measurement results, the ΦΔ of talaporfin sodium, protoporphyrin IX (PpIX), and lipidated PpIX (PpIX lipid) were measured as 0.53, 0.77, and 0.87, respectively. In addition, the ΦΔ values of PpIX in a hypoxic and oxic solution were evaluated, since tumors are associated with regions of hypoxia. The measured ΦΔ indicated a same value at high (DO: 20%) and low (DO: 1%) oxygen concentrations. Using the measured ΦΔ, the amount of [Formula: see text] generated by the PSs was estimated using [[Formula: see text]] = D*ΦΔ, where D* is the total excited PS concentration. The generated [Formula: see text] amounts were little different at the high and the low oxygen concentrations, and the generated [Formula: see text] amount for each PS was different depending on each ΦΔ. The NIRS measurement determined the ΦΔ of talaporfin sodium, PpIX, and PpIX lipid. The quantitative evaluation based on the measured ΦΔ will support the development of PDT treatment monitoring and design.

A New handheld singlet oxygen detection system (SODS) and NIR light source based phantom environment for photodynamic therapy applications.

Photodynamic therapy (PDT) is an emerging treatment modality in various areas such as cancer treatment and disinfection. The photosensitizer and oxygen have crucial roles for effective PDT treatment. The quantitative evaluation of singlet oxygen, which is a gold standard for monitoring effective treatment, remains as an important problem for PDT. However, low quantum yield and low life span of the singlet oxygen make the system expensive, unnecessarily large and unadaptable for clinical usage. In our study, a new mobile singlet oxygen detection system (SODS) was designed to detect singlet oxygen illumination during PDT and a new singlet oxygen phantom environment was constituted to test the designed SODS system. The singlet oxygen phantom environment composed of fast switching led driver & microcontroller and led light source (1200-1300 nm radiation). The elements of the singlet oxygen detection system are optic filter and collimation, avalanche photodiode transimpedance amplifier, differential amplifier and a signal processing block. According to the performance evaluation of the system on the phantom environment, the presented SODS can measure the illuminations at 1270 nm wavelength between 10 ns and 15 µs timespans. The results showed that the proposed system might be a good candidate for clinical PDT applications.

Acid-sensitive ROS-triggered dextran-based drug delivery system for advanced chemo-photodynamic synergistic therapy.

In order to improve the treatment efficacy and reduce the side effects, the synergistic therapy has been effectively exploited in cancer treatment. Herein, we fabricated a kind of acid-sensitive ROS-triggered dextran-based drug delivery system (DHTD/Zn-TPP) for synergistic therapy, in which chemotherapeutics doxorubicin was conjugated to the dextran backbone via ROS cleavable thioketal conjugates while photosensitizer porphyrin (Zn-TPP) was encapsulated via acid-responsive metallic coordinated interaction. The structure and acid-responsive self-assemble behavior of DHTD/Zn-TPP were measured by 1 H NMR, Fourier transform infrared, dynamic laser scattering, and transmission electron microscopy. Further, the in vivo ROS-triggered DOX release and anticancer efficiency were evaluated toward HeLa cells and MCF-7 cells. All the data obtained verified that DHTD/Zn-TPP had a significantly improved cell growth inhibitory effect with light irritation due to the combined application of photodynamic-chemotherapy.

Hybrids of a 9-anthracenyl moiety and fluorescein as chemodosimeters for the detection of singlet oxygen in live cells.

Singlet oxygen (1O2) plays an important role in human innate immune response, plant physiology and anticancer photodynamic therapy (PDT). Therefore, its monitoring by convenient and sensitive methods (e.g. by detecting a fluorescence signal) by using non-toxic reagents would be advantageous. Known fluorogenic 1O2-chemodosimeters can potentially consume reducing agents in cells leading to the generation of toxic side products that limit their applications. In this paper we report on a series of 9-anthracenyl-fluorescein hybrids, which do not require any reducing agents for their reaction with 1O2. The selected compound 8d at a very low concentration of 100 nM is able to detect 1O2 in live human promyelocytic leukemia HL-60 cells with over 35-fold fluorescence signal enhancement within only 20 min assay time. This chemodosimeter is not toxic to HL-60 cells at concentrations ≤1 µM (higher concentrations were not tested) even at long incubation times ≤48 h.

Polylysine modified conjugated polymer nanoparticles loaded with the singlet oxygen probe 1,3-diphenylisobenzofuran and the photosensitizer indocyanine green for use in fluorometric sensing and in photodynamic therapy.

Conjugated polymer hybrid nanoparticles (NPs) loaded with both indocyanine green (ICG) and 1,3-diphenylisobenzofuran (DPBF) are described. The NPs are dually functional in that ICG acts as the photosensitizer, and DPBF as a probe for singlet oxygen (1O2 probe). The nanoparticle core consists of the energy donating host poly(9,9-dioctylfluorenyl-2,7-diyl)-co-(2,5-p-xylene) (PFP). The polymer is doped with the energy acceptor DPBF. Ratiometric fluorometric detection of singlet oxygen is accomplished by measurement of fluorescence at wavelengths of 415 and 458 nm. In addition, the shell of the positively charged polymeric nanoparticles was modified, via electrostatic interaction, with negatively charged PDT drugs ICG. The integrated nanoparticles of type ICG-DPBF-PFP display effective photodynamic performance under 808-nm laser irradiation. The 1O2 sensing behaviors of samples are evaluated based on the ratiometric fluorescent responses produced by DPBF and PFP. 1O2 can be fluorimetically sensed with a detection limit of 28 µM. The multifunctional nanoprobes exhibit effortless cellular uptake, superior photodynamic activity and a rapid ratiometric response to 1O2. Graphical abstractSchematic of a dual-functional nanoplatform for photodynamic therapy (PDT) and singlet oxygen (1O2) feedback. It offers a new strategy for self-monitoring photodynamic ablation. FRET: fluorescence resonance energy transfer. Indocyanine green is attached in the shell of nanoparticles, and 1,3-diphenylisobenzofuran is doped into the energy donating host conjugated polymer.

Novel ruthenium(ii) and iridium(iii) BODIPY dyes: insights into their application in photodynamic therapy in vitro.

Organic-metal complexes are promising molecules for use in photodynamic therapy (PDT). The aim of this study was to investigate in vitro effects of novel Ru(ii) and Ir(iii) BODIPY complexes for PDT. These hybrid organic-metal molecules (Ru-BD and Ir-BD) have been synthesized via reactions of a BODIPY precursor (BD) with a phenanthroline unit bearing Ru(ii) (3) and novel Ir(iii) (4) compounds. The crystal structures of the new distyryl BODIPY (BD) and Ru(ii) complex (3) are also reported. The photophysical and singlet oxygen generation properties of Ru-BD and Ir-BD were investigated in comparison with unsubstituted BODIPY (BD). Moreover, Ru-BD and Ir-BD have been biologically evaluated in vitro in chronic myeloid leukemia and cervical cancer cell lines in terms of photodynamic therapy efficacy in the presence of BD control. These complexes were not toxic in the dark but red light was needed to induce cell death. These data support the fact that Ru-BD could be accepted as a valuable photosensitizer-drug for further PDT treatment.

Construction and evaluation of tumor nucleus-targeting nanocomposite for cancer dual-mode imaging - Guiding photodynamic therapy/photothermal therapy.

To tackle the barrier of the insufficient intra-cellular delivery of reactive oxygen species (ROS) and heat, we designed a multifunctional nanoplatform to release ROS and heat directly in the cell nucleus for enhancing combined photodynamic therapy (PDT) and photothermal therapy (PTT) of tumors. As a photothermal agent, WS2 nanoparticles were adsorbed photosensitive Au25(Captopril)18- (Au25) nanoclusters via electrostatic interaction. And Dexamethasone (Dex), a glucocorticoid with nucleus targeting capability, played a key role in the intra-nuclear process of heat and ROS. PTT can increase intra-tumoral blood flow to promote Au25 produce more ROS for PDT. Under near infrared (NIR) laser irradiation at a single 808 nm, these nucleus targeting WS2 nanoplatforms showed a significant decreased cell viability of 18.2 ±â€¯1.7% and a high DNA damage degree of 59.6 ±â€¯8.3%. Furthermore, the WS2 nanoplatform could be further used for X-ray computed tomography (CT) images. Taken together, our study provided a new prospect for effectively diagnostic and enhancing PTT/PDT efficacy.

A folate-conjugated platinum porphyrin complex as a new cancer-targeting photosensitizer for photodynamic therapy.

A new folate-conjugated platinum porphyrin complex (Por 4) was synthesized and characterized. The singlet oxygen production of the conjugates was evaluated through a 1,3-diphenylisobenzofuran method. The targeting ability and subcellular localization of Por 4 were confirmed by confocal laser scanning microscopy in HeLa cells (overexpression of FR) as well as in A549 cells (low expression of FR). The results suggested that the modification of the carboxyl group with a porphyrin compound did not decrease the binding affinity of folic acid to FR positive cancer cells. Moreover, the MTT assay using HeLa cells and A549 cells verified the low cytotoxicity of Por 4 in the dark. Upon irradiation, Por 4 showed noticeable improvement in toxicity against cancer cells with the overexpression of FR. Upon the treatment of Por 4 at the concentration of 20 µM, the cell viability was determined as 22% and 75% for HeLa and A549 cells, respectively, indicating that the folate-conjugated platinum porphyrin complex could be a promising PDT agent for cancer with overexpression of the folate receptor.