Application Of Photodynamic Therapy Research Articles

Charge Transfer-Promoted Excited State of a Heavy-Atom-Free Photosensitizer for Efficient Application of Mitochondria-Targeted Fluorescence Imaging and Hypoxia Photodynamic Therapy.

Conventional photosensitizers (PSs) used in photodynamic therapy (PDT) have shown preliminary success; however, they are often associated with several limitations including potential dark toxicity in healthy tissues, limited efficacy under acidic and hypoxic conditions, suboptimal fluorescence imaging capabilities, and nonspecific targeting during treatment. In response to these challenges, we developed a heavy-atom-free PS, denoted as Cz-SB, by incorporating ethyl carbazole into a thiophene-fused BODIPY core. A comprehensive investigation into the photophysical properties of Cz-SB was conducted through a synergistic approach involving experimental and computational investigations. The enhancement of intersystem crossing (kISC) and fluorescence emission (kfl) rate constants was achieved through a donor-acceptor pair-mediated charge transfer mechanism. Consequently, Cz-SB demonstrated remarkable efficiency in generating reactive oxygen species (ROS) under acidic and low-oxygen conditions, making it particularly effective for hypoxic cancer PDT. Furthermore, Cz-SB exhibited good biocompatibility, fluorescence imaging capabilities, and a high degree of localization within the mitochondria of living cells. We posit that Cz-SB holds substantial prospects as a versatile PS with innovative molecular design, representing a potential "one-for-all" solution in the realm of cancer phototheranostics.

Compounding Methylene Blue with Selenium-decorated Graphene Quantum Dots to Improve Singlet Oxygen Production for Photodynamic Therapy Application.

Graphene quantum dots (GQDs) are known as suitable material to be applied in different fields such as photodynamic therapy (PDT). Herein, GQDs were synthesized by the pyrolysis method and then decorated with selenium (Se). Afterward, they were combined with methylene blue (MB) to increase singlet oxygen generation as well as to apply them more effectively in the PDT method. Furthermore, GQDs were investigated by transmission electron microscope (TEM), photoluminescence spectrum (PL), Fourier-transform infrared spectroscopy (FTIR), field emission scanning electron microscope (FESEM), reactive oxygen species (ROS) measurement, and cytotoxicity measurement. GQDs showed no dependence on the excitation wavelength. The result of ROS measurement proves that the combination of GQD-Se and MB increases singlet oxygen production. Moreover, afterglow measurement approved the beneficial effect of GQD-Se on even deep and near skin tumor treatment. Cytotoxicity measurements under dark conditions, cell viability, and the side effects on human cells were determined by (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) (MTT) assay. Our findings show that under dark conditions, even high concentrations of nanoparticles have no significant effect on cell viability. These findings and the high biocompatibility of GQDs indicate the effective application of GQD-Se-MB in PDT.

Cell Membrane-Coated Biomimetic Nanoparticles in Cancer Treatment.

Nanoparticle-based drug delivery systems hold promise for cancer treatment by enhancing the solubility and stability of anti-tumor drugs. Nonetheless, the challenges of inadequate targeting and limited biocompatibility persist. In recent years, cell membrane nano-biomimetic drug delivery systems have emerged as a focal point of research and development, due to their exceptional traits, including precise targeting, low toxicity, and good biocompatibility. This review outlines the categorization and advantages of cell membrane bionic nano-delivery systems, provides an introduction to preparation methods, and assesses their applications in cancer treatment, including chemotherapy, gene therapy, immunotherapy, photodynamic therapy, photothermal therapy, and combination therapy. Notably, the review delves into the challenges in the application of various cell membrane bionic nano-delivery systems and identifies opportunities for future advancement. Embracing cell membrane-coated biomimetic nanoparticles presents a novel and unparalleled avenue for personalized tumor therapy.

Hybrid Sono-Photodynamic Combination Therapy Mediated by Water-Soluble Gallium Phthalocyanine Enhances the Cytotoxic Effect against Breast Cancer Cell Lines.

Breast cancer is a life-threatening disease that is gaining increasing importance due to its rising incidence, highlighting the need for novel treatment methods with the least disadvantages. Recently, scientists have focused on developing therapeutic treatment modalities for effective cancer treatment. In contrast to conventional cancer treatment methods such as immunotherapy, surgery, chemotherapy, or radiotherapy, photodynamic therapy (PDT) is gaining prominence. Besides, sonodynamic treatment (SDT) is a noninvasive therapeutic approach that uses ultrasound to induce high tissue penetration. In both methods, sensitizers are activated to generate cytotoxic reactive oxygen species such as •OH and 1O2. In particular, the combined use of hybrid and complementary treatment methods has become an important modality in cancer treatment in recent years. Sono-photodynamic therapy (SPDT), which is an important method applied in combination with PDT and SDT, has started to be preferred in terms of reducing potential side effects compared to monotherapy. One of the most important types of sensitizers used in PDT and SDT is known as phthalocyanines (Pcs). Motivated by these facts, this research presents the sono-photochemical, in vitro cytotoxicity, and theoretical evaluation of water-soluble gallium phthalocyanine (GaPc). The results indicate that the quantum yield of the generation of singlet oxygen increased in sono-photochemical studies (ΦΔ = 0.94), compared to photochemical studies (ΦΔ = 0.72). In vitro analyses revealed that GaPc did not exhibit significant cytotoxic effects at the specified varying concentration doses (1-20 μM). Furthermore, GaPc-mediated SPDT triggered cell death by inducing reactive oxygen species formation in the breast cancer cell line (MCF-7). The interaction mechanism of the GaPc with EGFR and VEGFR2 target proteins, which are critical regulators of metastasis, proliferation, and angiogenesis, was investigated by molecular docking simulation. GaPc has effective binding affinities against target proteins, and this affinity was found to be the highest against VEGFR2. Molecular docking results showed a good correlation with the obtained biological results. Eventually, this molecular building of the efficient water-soluble phthalocyanine-based sensitizer is a potential therapeutic for PDT, SDT, and SPDT applications.

Engineering Metal Halide Perovskite Nanocrystals with BODIPY Dyes for Photosensitization and Photocatalytic Applications.

The sensitization of surface-anchored organic dyes on semiconductor nanocrystals through energy transfer mechanisms has received increasing attention owing to their potential applications in photodynamic therapy, photocatalysis, and photon upconversion. Here, we investigate the sensitization mechanisms through visible-light excitation of two nanohybrids based on CsPbBr3 perovskite nanocrystals (NC) functionalized with borondipyrromethene (BODIPY) dyes, specifically 8-(4-carboxyphenyl)-1,3,5,7-tetramethyl-4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BDP) and 8-(4-carboxyphenyl)-2,6-diiodo-1,3,5,7-tetramethyl-4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (I2-BDP), named as NC@BDP and NC@I2-BDP, respectively. The ability of I2-BDP dyes to extract hot hole carriers from the perovskite nanocrystals is comprehensively investigated by combining steady-state and time-resolved fluorescence as well as femtosecond transient absorption spectroscopy with spectroelectrochemistry and quantum chemical theoretical calculations, which together provide a complete overview of the phenomena that take place in the nanohybrid. Förster resonance energy transfer (FRET) dominates (82%) the photosensitization of the singlet excited state of BDP in the NC@BDP nanohybrid with a rate constant of 3.8 ± 0.2 × 1010 s-1, while charge transfer (64%) mediated by an ultrafast charge transfer rate constant of 1.00 ± 0.08 × 1012 s-1 from hot states and hole transfer from the band edge is found to be mainly responsible for the photosensitization of the triplet excited state of I2-BDP in the NC@I2-BDP nanohybrid. These findings suggest that the NC@I2-BDP nanohybrid is a unique energy transfer photocatalyst for oxidizing α-terpinene to ascaridole through singlet oxygen formation.

Design and Synthesis of Difluoroboronite Curcuminoid derivatives for application in photodynamic therapy

This research paper describes the synthesis of two derivatives, 1 and 2, using aldehydes containing acid-sensitive groups. Both derivatives are of the donor-acceptor-donor type and exhibit absorption and emission in the red region. Derivative 1 has an absorption peak at 647 nm and an emission peak at approximately 713 nm. These molecules possess intramolecular charge transfer properties, allowing them to populate a triplet state that produces singlet oxygen, which plays a crucial role in cell death. Furthermore, the acid-sensitive groups on these derivatives enable selective accumulation in slightly acidic cancer cells. The cellular uptake of these derivatives can be enhanced through the formation of nanoaggregates, with average particle sizes of 112 nm and 81 nm for 1 and 2, respectively. While derivative 2 has a higher capacity for singlet oxygen production (φΔ∼0.40) and better fluorescence quantum yield than derivative 1, both molecules have high molar absorption coefficients and can serve as potential photosensitizers for cancer treatment.

Application of photodynamic therapy in gastrointestinal disorders

Application of photodynamic therapy in gastrointestinal disorders

Potential of Ruthenium as a photosensitizer in radiation-activated Photodynamic Therapy (radioPDT)

In Photodynamic Therapy (PDT), light is used to activate photosensitizers (PS) to generate reactive oxygen species (ROS) as a cell-killing mechanism. However, PDT's application is limited to the surface and small size tumors because of the inefficiency of light in penetrating larger and deep-seated tumors. We have developed novel nanoparticles (NPs) that can be activated by radiation, a process known as the radiation-activated PDT (radioPDT). In our studies we developed a new variant of pegylated poly-lactic-co-glycolic (PEG-PLGA) encapsulated nanoscintillators (NSC) and ruthenium-based photosensitizer (Ru/rPDT) that exhibits minimal cell toxicity while having significant cell killing effect upon radiation activation. Our data suggest that radioPDT with Ru/rPDT can be a more effective strategy than previous protoporphyrin-based iterations in treating many deep-seated tumors.Introduction and Background: Toxicity and normal tissue damage are limiting factors for the application of radiotherapy (RT) where higher doses of radiation is required to cure deep-seated tumor such as prostate cancer. In Photodynamic Therapy (PDT), photosensitizers (PS) are activated by light to generate reactive oxygen species (ROS) to kill tumor cells. However, the main limitation of the current PDT is the limited tissue penetration of PS-activating light. Thus, PDT cannot be effectively used to treat deep-seated and larger size tumors. RT has higher tissue penetration depth, making the radiation-activated PDT (radioPDT) advantageous in treating deep seated tumors.We aim to develop novel radioPDT nanoparticles (NP) with more efficient anti-cancer therapeutic effect in vitro and in vivo to enhance targeted radiotherapy.Methods: LaF3:Ce3+ nanoscintillators (NSCs) were synthesized in a single step wet chemistry technique. The NSCs along with Ruthenium-based PS (Ru) with matching excitation/emission spectra were successfully encapsulated in PEG-PLGA. UV-Vis spectrometry and inductively coupled plasma mass spectrometry (ICP-MS) were used to confirm the presence of NSCs and Ru, and dynamic light scattering (DLS) and transmission electron microscopy (TEM) were used to determine the size of NP. Singlet oxygen generation was measured by Singlet Oxygen Sensor Green (SOSG) and direct singlet oxygen fluorescence. RadioPDT therapeutic potential was evaluated in PC3 prostate cancer cell under radiation by Alamar Blue cell viability assay.Results: UV-Vis spectrometry and ICP-MS determined the successful PEG-PLGA encapsulation of NSC and Ru. The TEM imaging confirmed the encapsulation NSC inside the nanocarrier PEG-PLGA. TEM and DLS measurements showed the size of radioNP ranged from 90nm to 150nm with polydispersity index of <0.3. Singlet oxygen generation by Ru/rPDT NPs was greater than PPIX based radioPDT (PPIX/rPDT) NPs. Furthermore, the direct measurement of singlet oxygen generation with fluorescence spectroscopy of Ru/rPDT showed preserved singlet oxygen yield and no evidence of quenching. The Ru/rPDT and PPIX/rPDT showed minimal PC3 cell cytotoxicity in dark conditions. The PC3 cell killing efficiency was comparable between Ru/rPDT and PPIX/rPDT either under light or radiation activation.Conclusion: Our in vitro studies show Ru/rPDT significantly increases anti-cancer therapeutic effect of RT, with minimal toxicity. Future studies will refine in vivo NP biodistribution, dosing, and RT dose/fractionation schemes.

Effects of metalation on the PDT activity of arene ruthenium porphyrin-based photosensitizers on prostate cancer

SignificanceProstate cancer is a major health issue (second most common cancer in men worldwide). Despite therapeutic advances and early detection, many side effects are often observed during treatment. Photodynamic therapy (PDT) is a promising therapy to reduce side effects, many 2nd and 3rd generation of photosensitizer (PS) are poorly soluble in aqueous media, limiting their attractiveness. ApproachWe have developed and tested 3rd generation of PS vectorized by arene-ruthenium (Ru) complexes coordinated to tetrapyridylporphin (tpp-2H), Zn-tetrapyridylporphin (tpp-Zn) or Co-tetrapyridylporphin (tpp-Co). ResultsTwo of the three complexes show a good efficacy. The compounds localize into the cytoplasm. An analysis of the apoptotic process shows a cleavage of poly-ADP ribose polymerase (PARP) and a strong induction of DNA fragmentation following irradiation. ConclusionsArene-ruthenium tetrapyridylporphin complexes are excellent candidates for PDT application. The addition of the metal shows a decrease (tpp-Zn) or no effects (tpp-Co), compared to the metal free photosentizer (tpp-2H).

Photosensitizers Based on Bichromophoric Dyads Combining Ru(II)-Polypyridyl Complexes and Dissymmetric Perylene Monoimide Derivatives: The Nontrivial Role of Ligand Substitution.

The covalent modification of Ru(II) polypyridyl complexes (RPCs) with organic chromophores is a powerful strategy to obtain metal-based photosensitizer agents (PSs) with improved performance for application in photodynamic therapy (PDT). In this respect, perylene-imides are of particular interest due to their rich chemical-physical repertoire, and it is therefore quite surprising that their combination with RPCs has been poorly considered so far. Herein, we report on the photophysical behavior of two newly synthesized RPCs bearing a perylene monoimide appendant (PMI-Ad). Differently from the majority of RPCs-perylene-imides dyads, these chromophores are dissymmetric and are tethered to the metal centers through a single C-C bond in the 3- or 5-position of 1,10-phenanthroline (Ru-3PMI-Ad and Ru-5PMI-Ad). Both compounds show excellent singlet oxygen photosensitizing activity, with quantum yields reaching >90% in the case of Ru-3PMI-Ad. A combined spectroscopic and theoretical analysis, also involving transient absorption and luminescence lifetime measurements, demonstrates that both compounds undergo intersystem crossing on a very fast time scale (tens of picoseconds) and with high efficiency. Our results further demonstrate that the increased electron delocalization between the metal center and the PMI-Ad chromophore observed for Ru-3PMI-Ad additionally contributes to increase the singlet oxygen quantum yields by prolonging the lifetime of the triplet state.

“Three birds with one stone” nanoplatform: Efficient near‐infrared‐triggered type‑I AIE photosensitizer for mitochondria‐targeted photodynamic therapy against hypoxic tumors

AbstractCurrently three major problems seriously limit the practical application of cancer photodynamic therapy (PDT): (i) the hypoxic tumor microenvironment (TME); (ii) low generation efficiency of toxic reactive oxygen species (ROS) in aggregates and (iii) shallow tissue penetration depth of excitation light. Very limited approaches are available for addressing all the above three problems with a single design. Herein, a rational “three birds with one stone” molecular and nanoengineering strategy is demonstrated: a photodynamic nanoplatform U‐Ir@PAA‐ABS based on the covalent combination of lanthanide‐doped upconversion nanoparticles (UCNPs) and an AIE‐active dinuclear Ir(III) complex provides a low oxygen concentration‐dependent type‐I photochemical process upon 980 nm irradiation by Föster resonance energy transfer (FRET). U‐Ir@PAA‐ABS targets mitochondria and has excellent phototoxicity even in severe hypoxia environments upon 980 nm irradiation, inducing a dual‐mode cell death mechanism by apoptosis and ferroptosis. Taken together, the in vitro and in vivo results demonstrate a successful strategy for improving the efficacy of PDT against hypoxic tumors.

Efficacy of photodynamic therapy as an adjunct to scaling and root planing on clinical parameters and microbial composition in subgingival plaque of periodontitis patients: A split-mouth randomized clinical trial.

The aim of this study was to assess the efficacy of photodynamic therapy (PDT) as an adjunct to scaling and root planing (SRP) on clinical parameters and microbial composition in subgingival plaque of periodontitis patients. Seventeen patients were included in this split-mouth randomized clinical trial. Sites with probing pocket depth (PPD) ≥5mm in combination with bleeding on probing in different quadrants were randomized into the control group, the group with a single PDT application right after SRP, and the group with three repeated PDT applications 1week after SRP. The subgingival plaque was collected for 16S rRNA gene sequencing at baseline, Week 2, and Week 8. Seventeen patients with 60 sites completed this 8-week follow-up, and 157 subgingival plaques were successfully analyzed by sequencing. Significant improvements were observed in two primary outcomes: PPD at Week 8 and subgingival microbial composition. Compared to the control group, the repeated-PDT group showed a notable improvement in PPD, substantial alterations in the microbial profile, including a reduction in α-diversity and anaerobic bacteria, and an increase in aerobic bacteria at Week 2. Secondary outcomes, such as clinical attachment level and sulcus bleeding index, also showed improvement at Week 8. Furthermore, both the single- and repeated-PDT groups exhibited a decrease in periodontopathogens and an increase in beneficial bacteria compared with baseline. PDT promotes changes in the microbial composition of periodontitis patients' subgingival plaque in a direction favorable to periodontal health, and repeated PDT is a promising adjunctive therapy for periodontal treatment.

Applications of photodynamic therapy in keratitis.

Keratitis is corneal inflammatory disease which may be caused by several reason such as an injury, allergy, as well as a microbial infection. Besides these, overexposure to ultraviolet light and unhygienic practice of contact lenses are also associated with keratitis. Based on the cause of keratitis, different lines of treatments are recommended. Photodynamic therapy is a promising approach that utilizes light activated compounds to instigate either killing or healing mechanism to treat various diseases including both communicable and non-communicable diseases. This review focuses on clinically-important patent applications and the recent literature for the use of photodynamic therapy against keratitis.

Anion-π+ AIEgens for Fluorescence Imaging and Photodynamic Therapy.

Fluorescence imaging-guided photodynamic therapy (PDT) has attracted extensive attention due to its potential of real-time monitoring the lesion locations and visualizing the treatment process with high sensitivity and resolution. Aggregation-induced emission luminogens (AIEgens) show enhanced fluorescence and reactive oxygen species (ROS) generation after cellular uptake, giving them significant advantages in bioimaging and PDT applications. However, most AIEgens are unfavorable for the application in organisms due to their severe hydrophobicity. Anion-π+ type AIEgens carry intrinsic charges that can effectively alleviate their hydrophobicity and improve their binding capability to cells, which is expected to enhance the bioimaging quality and PDT performance. This concept summarizes the applications of anion-π+ type AIEgens in fluorescence imaging, fluorescence imaging-guided photodynamic anticancer and antimicrobial therapy in recent years, hoping to provide some new ideas for the construction of robust photosensitizers. Finally, the current problems and future challenges of anion-π+ AIEgens are discussed.

Application of Photodynamic Therapy in Cardiology.

The origins of photodynamic therapy (PDT) date back to 1904. Since then, the amount of research proving PDT and, consequently, its applicability to various disease states has steadily increased. Currently, PDT is mainly used in oncology to destroy cancer cells. It is being worked on for possible use in other medical fields as well, including cardiology. It can be used in the prevention of restenosis, often occurring after vascular surgical interventions, for destroying atherosclerotic plaques and as a new ablative method of ectopic centers in the treatment of atrial fibrillation. The purpose of this review is to summarize the knowledge to date regarding the therapeutic potential of using PDT for various pathological conditions in cardiology. The review also focuses on the current limitations associated with the use of PDT and identifies areas where more research is needed to develop better drug regimens. Materials and methods: The study analyzed 189 medical articles. The articles came from PubMed, Frontiers, Google Scholar, Science Direct and Web of Science databases. Through the excitation of light, a photosensitizer (PS) introduced into the body, the destruction of pathological cells occurs. PTD is widely used in oncology of the central nervous system (CNS). This process is made possible by the production of free oxygen radicals (ROS) and singlet oxygen, which generate oxidative stress that destroys sensitive cancer cells. In recent years, photosensitizers have also been discovered to have a strong affinity for macrophages that fill atherosclerotic plaques, making these compounds suitable for treating atherosclerosis. By inducing apoptosis of smooth muscle cells, inactivating basic fibroblast growth factor (FGF-β) and inhibiting endothelial cell hyperplasia, PDT can be used to prevent restenosis after surgical proceduresPDT appears to be a minimally invasive and highly effective therapeutic method, especially when combined with other therapeutic methods. Unfortunately, the small number of animal model studies and human clinical trials greatly limit the applicability of PDT on a wider scale. Current limitations, such as the depth of penetration, delivery of photosensitizer particles to the direct site of the lesion or the appropriate choice of photosensitizer in relation to the nature of the pathology, unfortunately make it impossible to replace current therapeutic approaches.

K+ Ions Crosslinked Kappa-Carrageenan/Methylene Blue Composite Film. Part-1: Synthesis, Characterization and Application as Controlled Release Device for Photodynamic Therapy Application

K+ ions crosslinked (KC/MB) Methylene blue photosensitizer loaded composite film is prepared for photodynamic therapy (PDT) application as Photosensitizer released by composite film can conveniently be controlled by using different quantities of K+ ions and this application is based on dynamic interaction between light with suitable wavelength, photosensitizer and molecular oxygen, promoting the death of the target tissue or bacterial cells. In this work, the Methylene Blue (MB) loaded Carrageenan polymeric film was prepared by the method of direct addition of MB into pre-polymerization solution of Carrageenan (KC). This composite film and plain KC film were characterized by FTIR, XRD and SEM analysis. The characteristic peaks of MB photosensitizer were obtained in FTIR spectrum of composite film. The composite film KC/MB shows prominence of amorphous nature may be due to MB is present in very small quantity. The SEM analysis reveals that the composite film (KC/MB) having much more smooth surface texture throughout the film. Finally, the result of effect of variation in degree of crosslinking on amount of MB release is, as the amount of K+ ions used to crosslink the film increases, MB release decreases.

Reduction of photodynamic damage of blood vessels in the protected region by (–)-epigallocatechin gallate

Photodynamic therapy (PDT) has been increasingly used in the clinical treatment of neoplastic, inflammatory and infectious skin diseases. However, the generation of reactive oxygen species (ROS) may induce undesired side effects in normal tissue surrounding the treatment lesion, which is a big challenge for the clinical application of PDT. To date, (–)-Epigallocatechin gallate (EGCG) has been widely proposed as an antiangiogenic and antitumor agent for the protection of normal tissue from ROS-mediated oxidative damage. This study evaluates the regulation ability of EGCG for photodynamic damage of blood vessels during hematoporphyrin monomethyl ether (Hemoporfin)-mediated PDT. The quenching rate constants of EGCG for the triplet-state Hemoporfin and photosensitized 1O2 generation are determined to be [Formula: see text] M−1S−1 and [Formula: see text] M−1S−1, respectively. The vasoconstriction of blood vessels in the protected region treated with EGCG hydrogel after PDT is lower than that of the control region treated with pure hydrogel, suggesting an efficiently reduced photodamage of Hemoporfin for blood vessels treated with EGCG. This study indicates that EGCG is an efficient quencher for triplet-state Hemoporfin and 1O2, and EGCG could be potentially used to reduce the undesired photodamage of normal tissue in clinical PDT.

X-ray luminescent nanocomposite LaF3:Tb/Citr@[Ru(bpy)2(nic)2]2+ as a model targeted delivery system for photopharmacology and photodynamic therapy

The study is devoted to the development of the concept of targeted delivery of pharmacological agents. A nanocomposite (NC) – (LaF3:Tb/Citr@RuBiNic), which is formed by luminescent nanoparticles (ScNPs) – LaF3: Tb/Citr and a photosensitive substance – [Ru(bpy)2(nic)2]2+ (where bpy = 2,2′ bipyridine and nic = nicotine (3-[(2S)-1-methylpyrrolidin-2-yl] pyridine) – (RuBiNic), in response to X-ray irradiation, emits quanta of visible light, as a result is released of a pharmacological agent – nicotine from the NC surface. In principle, when implementing the methods of photopharmacology, or photodynamic therapy, it allows controlling the desired physiological or therapeutic effect in a specific place and at the right time with high specificity of influence.To conduct research, LaF3:Tb/Citr nanoparticles were synthesized, and RuBiNic was used as a model photosensitive substance. The size and morphology (TEM), surface (FTIR-spectroscopy), thermogravimetric (TG/DTG/DTA) and X-ray structural analysis were carried out, SSA value and acid-base characteristics of the surface were determined. In the static mode at 25°С, the processes of adsorption immobilization of the RuBiNic complex on the surface of nanoparticles in the medium of an aqueous solution were investigated. Diffuse kinetics models, pseudo-first- and pseudo-second-order kinetics models, Langmuir and Freundlich models were used to quantitatively describe the equilibrium adsorption processes. The kinetics of RuBiNic adsorption is characterized by a mixed-diffusion mechanism. The pseudo-second-order model was also found to have a higher correlation coefficient than the pseudo-first-order model, confirming the chemisorption process. The data of fitting the adsorption isotherm according to the Langmuir adsorption model (r2 = 0.99) indicate chemisorption of RuBiNic on the surface of ScNPs LaF3:Tb/Citr with a maximum adsorption capacity of 7.47 mg⋅g−1.The obtained data are useful for optimizing the conditions of adsorption immobilization of molecules of photosensitive substances on the surface of phosphors based on lanthanum fluoride. The LaF3:Tb/Citr@RuBiNic system shows potential for future applications in photopharmacology and X-ray photodynamic therapy.

A Comparison Between the Photodynamic Action of “Hypocrellin A” and “Pheophorbide A” Against Bacteria and SARS-CoV-2 Virus --- A MiniReview

Abstract: Hypocrellin A and Pheophorbide a are well-known organic chemicals that may be contained in herbal products. They can act as photosensitizers and have a strong photodynamic effect on bacteria. In any case, are these photosensitizers appropriate for photodynamic treatment against the SARS-CoV-2 infection? The principles of photodynamic therapy are the same regardless of the target. It causes selective cytotoxicity at the site of infection through activation of photosensitizer under light irradiation to generate cytotoxic reactive oxygen species (ROS), leading to the death of infected cells. Is antimicrobial photodynamic therapy a good choice against the SARS-CoV-2 virus? Methods: Nine electronic databases were searched, including WanFang Data, PubMed, Science Direct, Scopus, Web of Science, Springer Link, SciFinder, and China National Knowledge Infrastructure (CNKI), regardless of term, and language restrictions. All eligible studies were analyzed and summarized in this review. Results: “Hypocrellin A” and “Pheophorbide a” were effective for bacterial and SARS-CoV-2 in photodynamic therapy. 99.98 % of S. aureus was killed when incubated with the 10-3 M Hypocrellin A and illuminated a 490 nm in 30 mW/cm2 for 120 min. The difference was Pheophorbide a could also inhibit gram-negative bacteria, such as P. aeruginosa with a concentration of 1 µg/ml for 2 hr irradiated of a 671 nm laser in 0.3 W of 1 J, and a nearly 100 % suppression rate. “Hypocrellin A” and “Pheophorbide a” with antiviral activity, and virucidal effects for preventing and treating the infection. Conclusion: Based on previous studies, “Hypocrellin A” and “Pheophorbide a” are photosensitizers used for photodynamic therapy against bacteria or SARS-CoV-2, however, much more works need to be done in the future including the development of a better way for systematic infectious disease, and its correlated infections for the application of photodynamic therapy.

Cancer-Thylakoid Hybrid Membrane Camouflaged Thulium Oxide Nanoparticles with Oxygen Self-Supply Capability for Tumor-Homing Phototherapy.

Nanomaterials that generate reactive oxygen species (ROS) upon light irradiation have significant applications in various fields, including photodynamic therapy (PDT) that is widely recognized as a highly momentous strategy for the eradication of cancer cells. However, the ROS production rate of photosensitizers, as well as the tumor hypoxia environment, are two major challenges that restrict the widespread application of PDT. In this study, a cancer-thylakoid hybrid membrane-camouflaged thulium oxide nanoparticles (Tm2O3) for tumor-homing phototherapy through dual-stage-light-guided ROS generation and oxygen self-supply is developed. Tm2O3 as a type II photosensitizer are viable for NIR-stimulated ROS generation due to the unique energy levels, large absorption cross section, and long lifetime of the 3H4 state of Tm ions. The thylakoid membrane (TK) plays a catalase-like role in converting hydrogen peroxide into oxygen and also acts as a natural photosensitizer that can generate lethal ROS through electron transfer when exposed to light. In addition, fluorescence dye DiR is embedded in the hybrid membrane for in vivo tracing as well as photothermal therapy. Results show that tumors in Tm2O3@TK-M/DiR group are effectively ablated following dual-stage-light irradiation, highlighting the promising potential of rare-earth element-based type II photosensitizers in various applications.