Ce6 Concentration Research Articles

Non-interference delivery of Ce6 and DOX in NIR light-responsive liposomes for synergetic cervical cancer therapy

Multi-model combination treatment of malignant tumors can make up for the shortcomings of single treatment through multi-target and multi-path to achieve more ideal tumor treatment effect. However, the mutual interference of different drugs in the delivery process in vivo and the difficulty of effective drug accumulation in tumor cells are the bottlenecks of combined therapy. To this project, light-responsive liposomes loading doxorubicin (DOX) and chlorin e6 (Ce6) (DOX-Ce6-Lip) without mutual interference were engineered by thin film hydration method. This kind of nano-drug delivery system increased the drugs concentration accumulated in tumor sites through enhanced permeability and retention effect, and reduced the toxic and side effects of drugs on normal tissues in vivo. In addition, after entering the tumor cells, Ce6 produced a large number of reactive oxygen species under 660 nm NIR laser irradiation, which further oxidized the unsaturated fatty acid chain in the liposomes and caused the collapse of the liposomes, thus realizing the stimulus-responsive release of Ce6 and DOX. The concentrations of DOX and Ce6 in the tumor cells rapidly reached the peak and achieved a more effective combination of chemotherapy and photodynamic therapy (PDT). Consequently, DOX-Ce6-Lip followed by 660 nm NIR irradiation achieved an efficient tumor growth inhibition of 71.90 ± 3.14%, indicating the versatile potential of chemotherapy and PDT. In conclusion, this study provides a delivery scheme for drugs with different solubilities and an effectively combined anti-tumor therapy method.

Modulation of tumour hypoxia by ultrasound-responsive microbubbles to enhance the sono-photodynamic therapy effect on triple-negative breast cancer

Sono-photodynamic therapy (SPDT) is an oxidative stress-dependant antitumour treatment modality. Due to the hypoxic tumour microenvironment, the antitumour effect of SPDT is limited. In this study, we developed lipid vesicles to transport a photosensitizer (chlorin e6, Ce6) and oxygen into tumours to promote SPDT efficiency on triple-negative breast cancer in vitro and in vivo. The results showed that compared with the same concentration of free Ce6, Lipo-Ce6 produced a higher singlet oxygen level under light irradiation. Cellular Lipo-Ce6 accumulation was 4-fold higher than that of free Ce6. The cytotoxicity on 4T1 cells caused by Lipo-Ce6-SPDT was significantly stronger than that caused by free Ce6-SPDT, and oxygen microbubbles (O2MB) further enhanced the cytotoxicity of Lipo-Ce6-SPDT under hypoxic conditions. Cellular ROS production in the Lipo-Ce6-SPDT+O2MB group was approximately 2.5-fold higher than that in the Lipo-Ce6-SPDT+C3F8MB group. Furthermore, O2MB rapidly relieved 4T1 subcutaneous xenograft hypoxia conditions under ultrasound exposure and significantly improved the antitumour activity of SPDT in vivo. These results indicate that the combination of O2MB and a high-activity liposome photosensitizer can significantly enhance the antitumour efficiency of SPDT for hypoxic tumours.

Application of a Dual-Probe Coloading Nanodetection System in the Process Monitoring and Efficacy Assessment of Photodynamic Therapy: An In Vitro Study.

The oxygen-consuming property of photodynamic therapy (PDT) affects its effects and aggravates tumor hypoxia, thus upregulating the vascular endothelial growth factor (VEGF) to exacerbate tumor metastasis and lead to treatment failure. Therefore, it is necessary to monitor the dynamic changes in the factors related to PDT and tumor development trends in real time, thus helping to improve PDT efficiency. This study fabricated a fluorescent probe, TPE-2HPro, and a fluorescein-labeled aptamer probe, FAM-AptamerVEGF, to detect hydrogen peroxide (H2O2) and VEGF through the photoinduced electron-transfer effect and the specific affinity of the aptamer to VEGF, respectively. The two probes were loaded into the inner pores and absorbed on the surface of polydopamine coating-wrapped mesoporous silica nanoparticles (MSN@PDA) to construct the dual-probe-loaded system, MSNTH@PDAApt, which was kept stable in fetal bovine serum (FBS) solution and achieved pH-responsive release behavior, thus helping to increase the accumulation of the two probes in tumor cells. The dichloroacetic acid-mediated in vitro antitumor tests showed that the changing trends of H2O2 and VEGF levels were consistent with the results of related mechanism studies and could be monitored by MSNTH@PDAApt. The in vitro chlorin e6 (Ce6)-mediated PDT treatment demonstrated that when the illumination condition was 650 nm, 50 mW/cm2 for 10 min, cells were more inclined to metastasis and invasion rather than death due to a substantial increase in VEGF expression at the low Ce6 concentrations. With the increase of the Ce6 concentration, the growth of the H2O2 level gradually exceeded that of VEGF, and the reactive oxygen species (ROS)-mediated cell death dominated when the Ce6 concentration was about 2 times its IC50 values. Besides, hypoxia also affected the H2O2 and VEGF changes. These results demonstrated that MSNTH@PDAApt could precisely monitor and assess the tumor development trends during PDT treatment, thus helping improve the treatment effect.

Response surface methodological approach for optimization of photodynamic therapy of onychomycosis using chlorin e6 loaded nail penetration enhancer vesicles.

Antimicrobial photodynamic inactivation (aPDI) has a tremendous potential as an alternative therapeutic modality to conventional antifungals in treatment of onychomycosis, yet the nail barrier properties and the deep-seated nature of fungi within the nails remain challenging. Therefore, the aim of this study was to prepare, optimize, and characterize Chorin e6 (Ce6) nail penetration enhancer containing vesicles (Ce6-nPEVs) and evaluate their photodynamic mediated effect against Trichophyton rubrum (T.rubrum); the main causative agent of onychomycosis. Optimization of the particle size and encapsulation efficiency of nPEVs was performed using a four-factor two-level full factorial design. The transungual delivery potential of the selected formulation was assessed in comparison with the free drug. The photodynamic treatment conditions for T.rubrum aPDI by free Ce6 was optimized using response surface methodology based on Box-Behnken design, and the aPDI effect of the selected Ce6-nPEVs was evaluated versus the free Ce6 at the optimized condition. Results showed that formulations exhibited high encapsulation efficiency for Ce6 ranging from 79.4 to 98%, particle sizes ranging from 225 to 859nm, positive zeta potential values ranging from +30 to +70mV, and viscosity ranging from 1.26 to 3.43cP. The predominant parameters for maximizing the encapsulation efficiency and minimizing the particle size of Ce6-nPEVs were identified. The selected formulation showed 1.8-folds higher nail hydration and 2.3 folds improvement in percentage of Ce6 up-taken by nails compared to the free drug. Results of the microbiological study confirmed the reliability and adequacy of the Box-Behnken model, and delineated Ce6 concentration and incubation time as the significant model terms. Free Ce6 and Ce6-nPEVs showed an equipotent in vitro fungicidal effect on T.rubrum at the optimized conditions, however Ce6-nPEVs is expected to show a differential effect at the in vivo level where the advantage of the enhanced nail penetration feature will be demonstrated.

Chlorin e6 mediated photodynamic therapy triggers resistance through ATM-related DNA damage response in lung cancer cells

ObjectivePhotodynamic therapy (PDT) is a promising strategy for the treatment of malignant tumors due to its high selectivity, limited-toxicity, and non-invasiveness. However, PDT can also induce DNA damage and subsequent repair response, which may reduce the efficacy of PDT. In the present study, we sought to explore the effect of chlorin e6 (Ce6)-mediated PDT on DNA damage and DNA damage response (DDR) in lung cancer cells. In addition, the effect of PDT combined with ATM inhibitor on molecules of DDR and the possibility of improving the efficacy of PDT were further investigated. Materials and methodsIn the in vitro study, lewis cells were submitted to Ce6 treatment (2, 4, 8, 16, 32 μg/mL). To determine the concentration of Ce6, uptake and toxicity of Ce6 mediated PDT were detected using flow cytometry (FACS), Confocal microscopy, and CCK-8. In the subsequent research, 8 μg/mL of Ce6 was the treatment condition for inducing PDT. The different post-irradiation placement times were further grouped under this condition (2, 4, 6, 12 h). Cellular reactive oxygen species (ROS), damage of DNA were measured by DCFH-DA probe, comet assay respectively. Then the expression of p-ATM, p53, and γ-H2A.X proteins related to DNA damage response, was detected by WB. The efficacy of Ce6 induced PDT was also demonstrated by Annexin-V/PI staining as well as the expression of PCNA, cleaved-caspase-3. On this basis, ATM inhibitor was applied to treat lewis cells combined with Ce6 (2, 4 h) to investigate whether the efficacy of PDT induced by Ce6 can be improved after the ATM-related DDR was blocked. The cell viability, apoptosis, and expression of associated proteins were assayed. ResultsAt 2–4 h after PDT treatment, ROS was dramatically elevated in lewis cells, DNA double-strand breaks (DDSB) occurred, as well as up-regulation of DDR proteins γ-H2A.X, p-ATM, and p53. At the same time, lewis cells did not undergo significant apoptosis. After ATM inhibition, the DDR was significantly blocked within 2–4 h after Ce6 induced PDT, along with a pronounced decrease in cell viability followed by a prominent increase of apoptosis. ConclusionCe6-mediated PDT generates ROS in a short period time, thus inducing DNA damage, ATM-related DDR as well as promoting resistance of lung cancer cells to PDT. Combining ATM inhibitor with PDT could effectively inhibit the DDR induced by PDT, thereby enhancing the efficacy. This study reveals a new resistance mechanism of PDT and proposes an intervention strategy.

In vitro and in vivo anti-periodontitis effects of combination treatment of photodynamic and antibiotic therapies

Objective: To investigate the effects of combination treatment of photodynamic therapy (PDT) based on photosensitizer chlorin e6 (Ce6) and antibiotic agent tinidazole (TNZ) against periodontitis both in vitro and in vivo. Methods: The Sprague-Dewley (SD) rat periodontitis model was constructed using the method of orthodontic wire ligation. After successful modeling, SD rats were randomly divided into the following 6 groups (3 rats in each group): positive control (Ctrl+), Ce6, TNZ, a mixture of Ce6 and TNZ (Ce6/TNZ), Ce6 with laser irradiation (Ce6+L), a mixture of Ce6 and TNZ with laser irradiation (Ce6/TNZ+L). Methyl thiazolyl tetrazolium (MTT) assay was used to assess the cytotoxic activities of Ce6 (concentration range: 0-20 mg/L), TNZ (concentration range: 0-16.6 mg/L) and their mixture (Ce6/TNZ) in mouse fibroblast L929 cells. Fluorescence probe method was applied to measure the production of reactive oxygen species in the dental plaque biofilms after various treatments with and without 5-minute laser irradiation at 635 nm at a power density of 0.5 W/cm2 (Ce6+L and Ce6/TNZ+L groups), thus to evaluate the PDT performances. Cell counting kit-8 (CCK-8) and live/dead staining were used to assess the antibacterial activity in each of the groups and the combination index (CI) of PDT combined with TNZ was calculated subsequently. Flow cytometry was utilized to detect the apoptosis-inducing effects of these treatments in macrophage RAW264.7 cells after processing with the apoptosis detection kit. The inhibitory effects of various treatments on the absorption of alveolar bone of SD rats were further evaluated in the periodontitis rats by using the micro-CT. Results: The survival rates of L929 cells in the preset concentration range were all above 90% in Ce6, TNZ and Ce6/TNZ groups. Upon laser irradiation, the plaque biofilms in Ce6 and Ce6/TNZ groups showed significant green fluorescence, indicating that large amounts of reactive oxygen species were triggered and generated significantly in the dental plaque biofilms. However, the survival rates of dental plaque microorganisms in 5 Ce6/TNZ concentrations were (85.4±5.5)%, (76.0±8.9)%, (61.7±0.6)%, (56.3±2.6)% and (43.5±0.6)% respectively, which were significantly lower than that in Ce6 only and TNZ only groups (P<0.01). The CI levle of each drug concentration group was less than 1.0, which showed a significant synergistic antibacterial efficiency. Stronger apoptotic activities were observed in Ce6+L and Ce6/TNZ+L groups compared with those in Ce6 only and Ce6/TNZ only groups (P<0.01). In periodontitis rats, Ce6/TNZ combined laser irradiation could effectively inhibit the absorption of alveolar bone. The alveolar bone volume and the ratio of bone volume and tissue volume were (1.49±0.07) mm3 and (47.08±0.71)%, respectively. The distances between cementoenamel junction to alveolar bone crest on buccal and palatal sites decreased to (2.13±0.07) mm and (1.94±0.10) mm respectively, showing a high inhibition efficiency. Conclusions: Ce6-mediated PDT combined with TNZ possessed notable synergistic effects against periodontitis, reflecting in the efficient antibacterial effect, the apoptosis-inducing action on macrophages, and the inhibitory efficacy on the alveolar bone absorption in vivo.

SR-A-Targeted Nanoplatform for Sequential Photothermal/Photodynamic Ablation of Activated Macrophages to Alleviate Atherosclerosis.

Cardiovascular and cerebrovascular diseases induced by atherosclerosis (AS) have become the dominant cause of disability and mortality throughout the world. The typical early pathological process of AS involves the activation of inflammatory macrophages in the vulnerable plaque. In this work, we first employed chitosan-coated carbon nanocages (CS-CNCs) as nanocarriers to load Chlorin e6 (Ce6) and then linked dextran sulfate (DS) to the outermost layer by electrostatic adsorption to create a multifunctional therapeutic nanoplatform, CS-CNCs@Ce6/DS. The DS of the nanoplatform can recognize and bind to the type A scavenger receptor (SR-A), which is expressed only on the activated macrophages of the arterial plaque, so the proposed nanoplatform selectively targets these macrophages and accumulates there. Furthermore, DS can competitively inhibit cellular endocytosis of oxidized low-density lipoproteins via blocking of SR-A. The rapid photothermal conversion capability of CS-CNCs enables efficient therapeutic delivery during photothermal therapy (PTT). Interestingly, near-infrared-accelerated drug release induced by initial 808-nm laser irradiation was observed, thus enhancing the Ce6 concentration in the atherosclerotic plaque area and the efficiency of photodynamic therapy (PDT). Sequential photothermal/photodynamic ablation of the activated macrophages reduced pro-inflammatory cytokine secretion and alleviated the proliferation and migration of smooth muscle cells. These finally resulted in the stabilization and shrinkage of atherosclerotic plaques, further inhibiting the development and exacerbation of AS. Therefore, this work achieved a "1 + 1 greater than 2" effect by providing a novel approach to the treatment of atherosclerotic plaques, which is promising for the prevention of AS-related diseases.

Chlorin e6-loaded sonosensitive magnetic nanoliposomes conjugated with the magnetic field for enhancing anti-tumor effect of sonodynamic therapy

In sonodynamic therapy (SDT), when Chlorin e6 (Ce6) accumulates in tumor tissues, its anti-tumor effect can be achieved by ultrasound activation. To increase the local drug concentration of Ce6 in tumor cells, we had established a novel drug delivery system, Ce6-loaded sonosensitive magnetic nanoliposome (Ce6/SML), which realized the targeting delivery by the external magnetic field. It was worth mentioning that the targeting release of Ce6/SML and the activation on Ce6 could be achieved simultaneously by ultrasound of SDT. In our study, after Ce6 was loaded into the sonosensitive magnetic nanoliposome (SML), the values of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in vitro and in vivo were determined, indicating the activation on Ce6 of ultrasound. The delivery system also displayed the tumor-targeting ability and anti-tumor activity, which associated with the determined tumor growth and expression levels of angiogenin (ANG), vascular endothelial growth factor (VEGF) and tumor necrosis factor-alpha (TNF-α). In conclusion, the Ce6/SML-SDT-Targeted delivery system could effectively enhance the anti-tumor activity of SDT and had a great potential application for the treatment of malignant tumors located in deep tissues.

Photodynamic inactivation mediated by methylene blue or chlorin e6 against Streptococcus mutans biofilm.

An appropriate photosensitizer (PS) for photodynamic inactivation should have a pronounced antimicrobial efficacy but low dark toxicity. The aim of this study is to investigate the concentration-dependent antimicrobial efficacies of methylene blue (MB) and chlorin e6 (Ce6), against Streptococcus mutans biofilms and to compare the efficacies of these two PSs. The 48-h S. mutans UA159 biofilms, grown on glass coverslips, were subjected to MB or Ce6 at 25, 50, 100 and 200 μM with or without irradiation by 660 nM LED light (L). Control groups (-PS-L and -PS + L) were also included. Viability of the biofilm was analyzed by CFU/biofilm and biofilm lactic acid production was quantified by an enzymatic assay. With irradiation, MB under 25 μM resulted in 2-log reduction in biofilm viability and 30-fold reduction in biofilm lactic acid production. However, this biofilm killing efficacy did not change with increasing MB concentration. The biofilm killing efficacy of Ce6 increased with increasing Ce6 concentrations and resulted in 5-log reduction in biofilm viability. The lactic acid inhibitory effect of Ce6 was significantly lower than MB at 25 μM (p<0.01) but higher than MB at 200 μM (p=0.05), although the difference at 200 μM did not reach statistical significance. No dark toxicity could be observed for MB whereas low dark toxicity could be seen for Ce6 when the concentration is above 50 μM. Ce6 under 200 μM showed to be a more powerful PS for photodynamic inactivation than MB. Both Ce6- and MB-based photodynamic inactivation are useful methods for biofilm control in caries prevention.

High Affinity of Chlorin e6 to Immunoglobulin G for Intraoperative Fluorescence Image-Guided Cancer Photodynamic and Checkpoint Blockade Therapy.

Cancer photodynamic therapy (PDT) represents an attractive local treatment in combination with immunotherapy. Successful cancer PDT relies on image guidance to ensure the treatment accuracy. However, existing nanotechnology for co-delivery of photosensitizers and image contrast agents slows the clearance of PDT agents from the body and causes a disparity between the release profiles of the imaging and PDT agents. We have found that the photosensitizer Chlorin e6 (Ce6) is inherently bound to immunoglobulin G (IgG) in a nanomolarity range of affinity. Ce6 and IgG self-assemble to form the nanocomplexes termed Chloringlobulin (Chlorin e6 + immunoglobulin G). Chloringlobulin enhances the Ce6 concentration in the tumor without changing its elimination half-life in blood. Utilizing the immune checkpoint inhibitor antiprogrammed death ligand 1 (PD-L1) (αPD-L1) to prepare αPD-L1 Chloringlobulin, we have demonstrated a combination of Ce6-based red-light fluorescence image-guided surgery, stereotactic PDT, and PD-L1 blockade therapy of mice bearing orthotopic glioma. In mice bearing an orthotopic colon cancer model, we have prepared another Chloringlobulin that allows intraoperative fluorescence image-guided PDT in combination with PD-L1 and cytotoxic T lymphocyte antigen 4 (CTLA-4) dual checkpoint blockade therapy. The Chloringlobulin technology shows great potential for clinical translation of combinatorial intraoperative fluorescence image-guided PDT and checkpoint blockade therapy.

Photodynamic enhancement of the activity of antibiotics used in urinary tract infections

Photodynamic therapy (PDT) has been proven to kill different microbial cells. However, to our knowledge, none of the available reports describes the modulatory effect of this therapy on the antibacterial activity of antibiotics against Escherichia coli rods being the main causative agent of urinary tract infections (UTIs). Therefore, the aim of our study was to verify if the PDT can enhance the antibacterial activity of antibiotics recommended in the treatment of UTIs. An attempt to determine the optimal conditions of PDT to enhance the bactericidal activity of ciprofloxacin, amikacin, and colistin has been made. In order to find the optimal antimicrobial conditions, the efficacy of four protocols associated with the use of different energy doses (70 and 120 J/cm2) and chlorin e6 (Ce6) concentrations (50 and 100 μg/mL) has been verified. The antibacterial effect of combined PDT and antibiotics was assessed by the time-kill assay. The best results were achieved for Ce6 at a concentration of 100 μg/mL and the energy dose 120 J/cm2 for bacterial suspensions treated with ciprofloxacin. Taken together, our results showed that PDT using Ce6 improves the antibacterial activity of antibiotics effectively inhibiting bacterial growth and being promising in the elimination of bacterial UTIs in humans.

Polydopamine Nanoparticles Enhance Drug Release for Combined Photodynamic and Photothermal Therapy.

Our study shows a facile two-step method which does not require the use of core templates to load a hydrophobic photosensitizer drug chlorin e6 (Ce6) within polydopamine (PDA) nanoparticles (NPs) while maintaining the intrinsic surface properties of PDA NPs. This structure is significantly different from hollow nanocapsules which are less stiff as they do not possess a core. To our knowledge, there exist no similar studies in the literature on drug loading within the polymer matrix of PDA NPs. We characterized the drug loading and release behavior of the photosensitizer Ce6 and demonstrated the therapeutic efficacy of the combined photodynamic (PDT) and photothermal therapy (PTT) from Ce6 and PDA, respectively, under a single wavelength of 665 nm irradiation on bladder cancer cells. We obtained a saturated loading amount of 14.2 ± 0.85 μM Ce6 in 1 nM PDA NPs by incubating 1 mg/mL dopamine solution with 140 μM of Ce6 for 20 h. The PDA NPs maintained colloidal stability in biological media, whereas the pi-pi (π-π) interaction between PDA and Ce6 enabled a release profile of the photosensitizer until day 5. Interestingly, loading of Ce6 in the polymer matrix of PDA NPs significantly enhanced the cell uptake because of endocytosis. An increased cell kill was observed with the combined PDT + PTT from 1 nM PDA-Ce6 compared to that with PTT alone with 1 nM PDA and PDT alone with 15 μM equivalent concentration of free Ce6. PDA-Ce6 NPs could be a promising PDT/PTT therapeutic agent for cancer therapy.

Multifunctional Micelles Dually Responsive to Hypoxia and Singlet Oxygen: Enhanced Photodynamic Therapy via Interactively Triggered Photosensitizer Delivery.

Nanoparticulate antitumor photodynamic therapy (PDT) has been suffering from the limited dose accumulation in tumor. Herein, we report dually hypoxia- and singlet oxygen-responsive polymeric micelles to efficiently utilize the photosensitizer deposited in the disease site and hence facilely improve PDT's antitumor efficacy. Tailored methoxy poly(ethylene glycol)-azobenzene-poly(aspartic acid) copolymer conjugate with imidazole as the side chains was synthesized. The conjugate micelles (189 ± 19 nm) obtained by self-assembly could efficiently load a model photosensitizer, chlorin e6 (Ce6) with a loading of 4.1 ± 0.5% (w/w). The facilitated cellular uptake of micelles was achieved by the triggered azobenzene collapse that provoked poly(ethylene glycol) shedding; rapid Ce6 release was enabled by imidazole oxidation that induced micelle disassembly. In addition, the singlet oxygen-mediated cargo release not only addressed the limited diffusion range and short half-life of singlet oxygen but also decreased the oxygen level, which could in turn enhance internalization and increase the intracellular Ce6 concentration. The hypoxia-induced dePEGylation and singlet oxygen-triggered Ce6 release was demonstrated both in aqueous buffer and in Lewis lung carcinoma (LLC) cells. The cellular uptake study demonstrated that the dually responsive micelles could deliver significantly more Ce6 to the cells, which resulted in a substantially improved cytotoxicity. This concurred well with the superior in vivo antitumor ability of micelles in a LLC tumor-bearing mouse model. This study presented an intriguing nanoplatform to realize interactively triggered photosensitizer delivery and improved antitumor PDT efficacy.

Ultrasound-assisted interaction between chlorin-e6 and human serum albumin: pH dependence, singlet oxygen production, and formulation effect

The interaction between chlorin e6 (Ce6) and human serum albumin (HSA) in the presence and absence of ultrasound have been investigated by ultraviolet-visible absorption spectroscopy and fluorescence spectroscopy. Ce6 is found to bind strongly to HSA at or near physiological pH conditions, but the strength of the binding is significantly weakened at lower pHs. The intrinsic fluorescence of HSA is incrementally quenched with increasing concentration of Ce6, and the quenching is enhanced after exposure to high-frequency ultrasound. Our experimental results suggest that Ce6-induced sonodynamic oxidation of HSA is mainly mediated by singlet oxygen. The formulation of Ce6 by high molecular weight polyvinylpyrrolidone (PVP) increased its stability in aqueous solutions and its quantum yield of singlet oxygen under ultrasound irradiation.

Photodynamic Therapy Using Photosensitizer-Encapsulated Polymeric Nanoparticle to Overcome ATP-Binding Cassette Transporter Subfamily G2 Function in Pancreatic Cancer.

Chlorin-based photosensitizers are commonly used in photodynamic therapy (PDT). These drugs are effluxed by cell membrane transporters, such as the ATP-binding cassette subfamily G member 2 (ABCG2). PDT efficacy is limited in tumor cells expressing high levels of these proteins. Pancreatic cancer cell lines AsPC-1 and MIA PaCa-2, which have high and low ABCG2 expression, respectively, were used, and ABCG2-overexpressing MIA PaCa-2 cells were generated. We compared PDT efficacy between chlorin e6 (Ce6) and cationic photosensitizer-encapsulated polymeric nanoparticle (PS-pNP), which is comprised with Ce6, polyethylene glycol, and polyethylenimine. The intracellular concentration of Ce6 was significantly higher in MIA PaCa-2 cells than in AsPC-1 or ABCG2-overexpressing MIA PaCa-2 cells. PS-pNP increased intracellular levels of the photosensitizer in all cell lines. The cell viability experiments indicated increased Ce6 resistance in ABCG2-overexpressing cells. In contrast, PS-pNP produced similar levels of cytotoxicity in each of the cancer cell lines tested. Singlet oxygen production was higher in cells treated with PS-pNP than in those treated with Ce6. Furthermore, in heterotopic and orthotopic AsPC-1 xenograft mouse models, PDT using PS-pNP significantly reduced tumor volume in comparison with that of Ce6 treatment. PS-pNP could increase intracellular Ce6 concentration, which was related with reduced ABCG2-mediated efflux of Ce6, thereby enhancing the effects of PDT in pancreatic cancer cells. Mol Cancer Ther; 16(8); 1487-96. ©2017 AACR.

Biodegradable nanocomplex from hyaluronic acid and arginine based poly(ester amide)s as the delivery vehicles for improved photodynamic therapy of multidrug resistant tumor cells: An in vitro study of the performance of chlorin e6 photosensitizer.

Photodynamic therapy (PDT), which enables the localized therapeutic effect by light irradiation, provides an alternative and complementary modality for the treatment of tumor. However, the aggregation of photosensitizers in acidic microenvironment of tumor and the non-targeted distribution of photosensitizers in normal tissues significantly affect the PDT efficiency. In this study, we developed a biodegradable nanocomplex HA-Arg-PEA from hyaluronic acid (HA) and arginine based poly(ester amide)s (Arg-PEA) as the nanocarrier for chlorin e6 (Ce6). HA enhanced the tumor-specific endocytosis mediated by the overexpression of CD44 receptor. Arg-PEA not only provide electrostatic interaction with HA to form self-assembled nanostructure, but also improve the monomerization of Ce6 at physiological pH as well as mildly acidic pH. The biodegradable characteristic of HA-Arg-PEA nanocomplex enabled the intracellular delivery of Ce6, in which its release and generation of singlet oxygen can be accelerated by enzymatic degradation of the carrier. The in vitro PDT efficiency of Ce6-loaded HA-Arg-PEA nanocomplex was examined in CD44 positive MDA-MB-435/MDR multidrug resistant melanoma cells. CD44-mediated uptake of Ce6-loaded HA-Arg-PEA nanocomplex significantly improved Ce6 level in MDA-MB-435/MDR cells within short incubation time, and the PDT efficiency in inhibiting multidrug resistant tumor cells was also enhanced at higher Ce6 concentrations. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1487-1499, 2017.

Cerenkov Radiation Induced Photodynamic Therapy Using Chlorin e6-Loaded Hollow Mesoporous Silica Nanoparticles.

Traditional photodynamic therapy (PDT) requires external light to activate photosensitizers for therapeutic purposes. However, the limited tissue penetration of light is still a major challenge for this method. To overcome this limitation, we report an optimized system that uses Cerenkov radiation for PDT by using radionuclides to activate a well-known photosensitizer (chlorin e6, Ce6). By taking advantage of hollow mesoporous silica nanoparticles (HMSNs) that can intrinsically radiolabel an oxophilic zirconium-89 (89Zr, t1/2 = 78.4 h) radionuclide, as well as possess great drug loading capacity, Ce6 can be activated by Cerenkov radiation from 89Zr in the same nanoconstruct. In vitro cell viability experiments demonstrated dose-dependent cell deconstruction as a function of the concentration of Ce6 and 89Zr. In vivo studies show inhibition of tumor growth when mice were subcutaneously injected with [89Zr]HMSN-Ce6, and histological analysis of the tumor section showed damage to tumor tissues, implying that reactive oxygen species mediated the destruction. This study offers a way to use an internal radiation source to achieve deep-seated tumor therapy without using any external light source for future applications.

FT-IR characterization of a theranostic nanoprobe for photodynamic therapy and epidermal growth factor receptor targets

Photodynamic Therapy (PDT) is an effective cancer treatment method based on light-activation of a photosensitizer in the presence of cellular oxygen. In an effort to develop a novel PDT agent for breast cancer treatment we report on the synthesis and characterization of a bifunctional theranostic nanoprobe; possessing both a photosensitizer agent (Chlorin e6) and tumor targeting agent – an Epidermal Growth Factor (EGF) complex which targets the EGF receptor. It’s effectiveness in arresting cancer cell growth was tested using the breast cancer cell line MDA-MB-468. FT-IR analysis confirms that carbodiimide chemistry was effective in creating covalent bonded complexes between the photosensitizer Chlorin e6 (Ce6) and cysteamine, and the EGF and α-lipoic acid, which exhibit excellent affinity for gold nanoparticles (AuNPs). In particular, for the Ce6-cysteamine complex FT-IR analysis shows peaks with significant increase in intensity at 1713, 1542, 2227cm−1 and a decrease at 941cm−1 and for the EGF-α-lipoic acid complex there are significant decreases in intensity at 1708, 1073, 947cm−1 and increases at 1542, 1680, 1108cm−1. These changes are consistent with the creation of amide bonds, loss of carboxylic acid, and modification of the NH and CO bonds. Conjugation of these complexes to AuNPs was confirmed by UV–vis and Dynamic Light Scattering experiments. MDA-MB-468 cells treated with the bifunctional nanoprobe exhibited similar cell death and mitochondrial activity at 10-fold smaller Ce6 concentrations when bound to AuNPs compared with free Ce6. In addition only half the exposure time was needed to achieve these effects compared with unbound Ce6.

Gonarthritis photodynamic therapy with chlorin e6 derivatives

BackgroundThe new methods of osteoarthritis treatment are in constant demand due to the complexity of the early diagnosis and therapy. Specific features of Сhlorin e6 derivative (Ce6) accumulation in knee joint tissues and the efficiency of photodynamic therapy (PDT) of gonarthritis were studied. MethodsThe experimental research was conducted on the model of posttraumatic gonarthritis on rabbits. The analysis of dynamics of change of Ce6 concentration in tissues of a knee joint was carried out by the method of fluorescent diagnostics. The intra-joint PDT was carried out using 662nm laser with energy density of 120–150J/cm2 and a sapphire diffuser. An analysis of slices was conducted to confirm the anti-inflammatory effect through apoptosis. ResultsThe method of fluorescent spectroscopy revealed that the highest amount of Ce6 was accumulated in the synovial membrane of a damaged knee joint 2.5h after its intravenous introduction. On 14th day after gonarthritis modeling but before PDT the synovial membrane showed signs of synovitis. On 21st day after PDT the synovial membrane possessed noticeable villous structure, and no cells of inflammatory nature were observed. ConclusionFluorescent diagnostics in knee joint tissues can be used in clinical practice of gonarthritis before, during and after PDT for monitoring the Ce6 accumulation and for treatment control. Optimal radiation energy density was determined to be 150J/cm2. In the studied time intervals (5–25min) no dependency of PDT effect on irradiation time at the same energy density was observed. The analysis of results of clinical and morphological research shows that PDT is a low-invasive method of gonarthritis treatment with a high degree of efficiency and selectivity.

Direct Fabrication of the Graphene-Based Composite for Cancer Phototherapy through Graphite Exfoliation with a Photosensitizer.

We report on the application of pristine graphene as a drug carrier for phototherapy (PT). The loading of a photosensitizer, chlorin e6 (Ce6), was achieved simply by sonication of Ce6 and graphite in an aqueous solution. During the loading process, graphite was gradually exfoliated to graphene to give its composite with Ce6 (G-Ce6). This one-step approach is considered to be superior to the graphene oxide (GO)-based composites, which required pretreatment of graphite by strong oxidation. Additionally, the directly exfoliated graphene ensured a high drug loading capacity, 160 wt %, which is about 10 times larger than that of the functionalized GO. Furthermore, the Ce6 concentration for killing cells by G-Ce6 is 6-75 times less than that of the other Ce6 composites including GO-Ce6.