RESUMO
While numerous methods exist for diagnosing tumors through the detection of miRNA within tumor cells, few can simultaneously achieve both tumor diagnosis and treatment. In this study, a novel graphene oxide (GO)-based DNA nanodevice (DND), initiated by miRNA, was developed for fluorescence signal amplification imaging and photodynamic therapy in tumor cells. After entering the cells, tumor-associated miRNA drives DND to Catalyzed hairpin self-assembly (CHA). The CHA reaction generated a multitude of DNA Y-type structures, resulting in a substantial amplification of Ce6 fluorescence release and the generation of numerous singlet oxygen (1O2) species induced by laser irradiation, consequently inducing cell apoptosis. In solution, DND exhibited high selectivity and sensitivity to miRNA-21, with a detection limit of 11.47 pM. Furthermore, DND discriminated between normal and tumor cells via fluorescence imaging and specifically generated O21 species in tumor cells upon laser irradiation, resulting in tumor cells apoptosis. The DND offer a new approach for the early diagnosis and timely treatment of malignant tumors.
Assuntos
DNA , Grafite , MicroRNAs , Fotoquimioterapia , Nanomedicina Teranóstica , Fotoquimioterapia/métodos , Humanos , MicroRNAs/análise , Grafite/química , Nanomedicina Teranóstica/métodos , DNA/química , Apoptose/efeitos dos fármacos , Imagem Óptica , Linhagem Celular Tumoral , Oxigênio Singlete/metabolismo , Oxigênio Singlete/química , Neoplasias/tratamento farmacológico , Neoplasias/diagnóstico por imagemRESUMO
Ferroptosis, a recently identified form of cell death, holds promise for cancer therapy, but concerns persist regarding its uncontrolled actions and potential side effects. Here, we present a semiconducting polymer nanoprodrug (SPNpro) featuring an innovative ferroptosis prodrug (DHU-CBA7) to induce sono-activatable ferroptosis for tumor-specific therapy. DHU-CBA7 prodrug incorporate methylene blue, ferrocene and urea bond, which can selectively and specifically respond to singlet oxygen (1O2) to turn on ferroptosis action via rapidly cleaving the urea bonds. DHU-CBA7 prodrug and a semiconducting polymer are self-assembled with an amphiphilic polymer to construct SPNpro. Ultrasound irradiation of SPNpro leads to the production of 1O2 via sonodynamic therapy (SDT) of the semiconducting polymer, and the generated 1O2 activated DHU-CBA7 prodrug to achieve sono-activatable ferroptosis. Consequently, SPNpro combine SDT with the controlled ferroptosis to effectively cure 4T1 tumors covered by 2-cm tissue with a tumor inhibition efficacy as high as 100 %, and also completely restrain tumor metastases. This study introduces a novel sono-activatable prodrug strategy for regulating ferroptosis, allowing for precise cancer therapy.
Assuntos
Ferroptose , Camundongos Endogâmicos BALB C , Polímeros , Pró-Fármacos , Semicondutores , Ferroptose/efeitos dos fármacos , Pró-Fármacos/farmacologia , Pró-Fármacos/química , Pró-Fármacos/uso terapêutico , Animais , Polímeros/química , Feminino , Linhagem Celular Tumoral , Camundongos , Terapia por Ultrassom/métodos , Nanopartículas/química , Humanos , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Antineoplásicos/química , Oxigênio Singlete/metabolismoRESUMO
Singlet oxygen is considered an important cell damaging agent due to its propensity to react with organic compounds. This drives the interest in developing methods for determination of 1O2. Simplicity of application and high sensitivity makes fluorescent probes a popular choice for in vivo 1O2 detection. Despite its proclaimed cell-impermeability, the commercially available Singlet Oxygen Sensor Green (SOSG) is widely applied to support assertions of 1O2 involvement in cell and tissue damage. Our investigation, however, demonstrate that different microbial species and cancer cells become fluorescent when exposed to SOSG under conditions which exclude generation of 1O2. Cells, permeabilized with chlorhexidine or by heat exposure under anaerobic conditions, exhibited SOSG fluorescence. Permeabilized cells could be stained with SOSG even 24 h post-permeabilization. Since SOSG is cell impermeable, the main factor that led to fluorescent staining was plasma membrane damage. Spectral analyses of different batches of SOSG revealed that SOSG endoperoxide (SOSG-EP) did not increase even after prolonged storage under the recommended conditions. The commercial preparations of SOSG, however, were not SOSG-EP free, which can produce erroneous results when SOSG staining is used as a proof of singlet oxygen production in vivo.
Assuntos
Corantes Fluorescentes , Oxigênio Singlete , Oxigênio Singlete/metabolismo , Humanos , Corantes Fluorescentes/química , Coloração e Rotulagem/métodos , Membrana Celular/metabolismoRESUMO
Despite the keen interest in potentially using the metal-organic framework (MOF) in advanced oxidation processes (AOPs), their application for environmental abatement and the corresponding degradation mechanisms have remained largely elusive. This study explores the use of cobalt-based MOF (CoMOF) for peroxymonosulfate (PMS) activation to remove tetracycline (TC) from water resources. Under optimal conditions, the given catalytic system could achieve a TC removal of 83.3%. Radical quenching tests and EPR analysis revealed that SO4â¢-, HOâ¢, â¢O2-, and 1O2 could participate in the catalytic degradation, but the discernible removal mechanism was mainly ascribed to the nonradical pathway induced by 1O2. At only 5 mg/L of CoMOF, the performance of the catalytic system was superior to that of PMS alone for different types of micropollutants. The CoMOF/PMS system could also reliably deal with typical anions in water, such as Cl-, SO42-, HCO3-, and PO43-. The MOF catalyst could last for four cycles with a minor decrease in reactivity of â¼30%. However, the removal performance decreased markedly when aromatic natural organic matter (NOM) were present in the water bodies, and the effectiveness was lower in alkaline or acidic environments. Our work offers insights into the catalytic degradation of CoMOF/PMS applied in contaminated water remediation and serves as a baseline for fabricating an efficient MOF with enhanced catalytic performance and stability.
Assuntos
Cobalto , Estruturas Metalorgânicas , Oxirredução , Peróxidos , Oxigênio Singlete , Poluentes Químicos da Água , Cobalto/química , Estruturas Metalorgânicas/química , Poluentes Químicos da Água/química , Peróxidos/química , Oxigênio Singlete/química , Catálise , Purificação da Água/métodos , Tetraciclina/químicaRESUMO
Meta-tetra(hydroxyphenyl)chlorin (m-THPC) is among the most potent photosensitizers, known for its high singlet oxygen generation efficiency. However, its clinical effectiveness in photodynamic therapy (PDT) is compromised by its propensity to aggregate in aqueous solutions, adversely affecting its photophysical properties and therapeutic potential. A series of spectroscopic techniques, including UV-Vis absorption, fluorescence spectroscopy, and laser flash photolysis, revealed that m-THPC exhibits significant aggregation, particularly in MeOH-PBS mixtures with MeOH content below 30%. This aggregation adversely affects its photophysical properties leading to reduced fluorescence quantum yield and most importantly reducing its singlet oxygen quantum yield. This study introduces the use of bovine serum albumin (BSA) to counteract the aggregation of m-THPC, aiming to enhance its solubility, stability, and efficacy in physiological settings. Through advanced spectroscopic analyses we demonstrated that the m-THPC@BSA complex exhibits restored photophysical properties characteristic for monomeric form. Notably, the complex showed a significant restoration of the singlet oxygen quantum yield (ΦΔ = 0.21) compared to aggregated m-THPC. These results underscore the potential of BSA to preserve the monomeric form of m-THPC, mitigating aggregation-induced losses in singlet oxygen production. Our findings suggest that BSA-mediated delivery systems could play a crucial role in optimizing the clinical utility of hydrophobic photosensitizers like m-THPC.
Assuntos
Fármacos Fotossensibilizantes , Soroalbumina Bovina , Oxigênio Singlete , Espectrometria de Fluorescência , Soroalbumina Bovina/química , Fármacos Fotossensibilizantes/química , Oxigênio Singlete/química , Oxigênio Singlete/metabolismo , Animais , Bovinos , Porfirinas/química , Fotoquimioterapia/métodos , Análise EspectralRESUMO
Two phthalocyanine derivatives tetra-peripherally substituted with tert-butylsulfonyl groups and coordinating either zinc(II) or platinum(II) ions have been synthesized and subsequently investigated in terms of their optical and photochemical properties, as well as biological activity in cellular, tissue-engineered, and animal models. Our research has revealed that both synthesized phthalocyanines are effective generators of reactive oxygen species (ROS). PtSO2tBu demonstrated an outstanding ability to generate singlet oxygen (ΦΔ = 0.87-0.99), while ZnSO2tBu in addition to 1O2 (ΦΔ = 0.45-0.48) generated efficiently other ROS, in particular ·OH. Considering future biomedical applications, the affinity of the tested phthalocyanines for biological membranes (partition coefficient; log Pow) and their primary interaction with serum albumin were also determined. To facilitate their biological administration, a water-dispersible formulation of these phthalocyanines was developed using Pluronic triblock copolymers to prevent self-aggregation and improve their delivery to cancer cells and tissues. The results showed a significant increase in cellular uptake and phototoxicity when phthalocyanines were incorporated into the customizable polymeric micelles. Moreover, the improved distribution in the body and photodynamic efficacy of the encapsulated phthalocyanines were investigated in hiPSC-delivered organoids and BALB/c mice bearing CT26 tumors. Both photosensitizers exhibit strong antitumor activity. Notably, vascular-targeted photodynamic therapy (V-PDT) led to complete tumor eradication in 84% of ZnSO2tBu and 100% of PtSO2tBu-treated mice, and no recurrence has so far been observed for up to five months after treatment. In the case of PtSO2tBu, the effect was significantly stronger, offering a wider range of light doses suitable for achieving effective PDT.
Assuntos
Indóis , Isoindóis , Fotoquimioterapia , Fármacos Fotossensibilizantes , Zinco , Animais , Indóis/química , Indóis/farmacologia , Humanos , Camundongos , Fármacos Fotossensibilizantes/química , Fármacos Fotossensibilizantes/farmacologia , Fármacos Fotossensibilizantes/síntese química , Zinco/química , Zinco/farmacologia , Platina/química , Platina/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Camundongos Endogâmicos BALB C , Linhagem Celular Tumoral , Oxigênio Singlete/metabolismo , Antineoplásicos/química , Antineoplásicos/farmacologia , Antineoplásicos/síntese químicaRESUMO
Rationale: One of the main challenges in chemotherapy is achieving high treatment efficacy while minimizing adverse events. Fully exploiting the therapeutic potential of an old drug and monitoring its effects in vivo is highly valuable, but often difficult to achieve. Methods: In this study, by encapsulating disulfiram (DSF) approved by US Food and Drug Administration, semiconducting polymer nanocomplex (MEHPPV), and Chlorin e6 into a polymeric matrix F127 via nanoprecipitation method, a nanosystem (FCMC) was developed for afterglow imaging guided cancer treatment. The characteristics, stability as well as the ability of singlet oxygen (1O2) production of FCMC were first carefully examined. Then, we studied the mechanism for enhanced anti-cancer efficiency and afterglow luminescence in vitro. For experiments in vivo, 4T1 subcutaneous xenograft tumor mice were injected with FCMC via the tail vein every three days and the antitumor effect of FCMC was evaluated by monitoring tumor volume and body weight every three day. Results: The nanosystem, which combines DSF with Ce6, can generates abundant 1O2 that enhances the antitumor activity of DSF. The in vivo results show that FCMC-treated group exhibits an obviously higher tumor-growth inhibition rate of 67.89% after 15 days of treatment, compared to the control group of F127@MEHPPV-CuET. Moreover, Ce6 also greatly enhances the afterglow luminescence intensity of MEHPPV and promotes the redshift of the afterglow emission towards the ideal near-infrared imaging window, thereby enabling efficient afterglow tumor imaging in vivo. Conclusions: This multifunctional nanoplatform not only improves the anticancer efficacy of DSF, but also enables monitoring tumor via robust afterglow imaging, thus exhibiting great potential for cancer therapy and early therapeutic outcome prediction.
Assuntos
Clorofilídeos , Dissulfiram , Polímeros , Porfirinas , Animais , Dissulfiram/farmacologia , Dissulfiram/química , Porfirinas/farmacologia , Porfirinas/química , Camundongos , Polímeros/química , Linhagem Celular Tumoral , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Antineoplásicos/administração & dosagem , Feminino , Camundongos Endogâmicos BALB C , Oxigênio Singlete/metabolismo , Nanopartículas/química , Semicondutores , Humanos , Ensaios Antitumorais Modelo de Xenoenxerto , Imagem Óptica/métodosRESUMO
Controlling the succession of chemical processes with high specificity in complex systems is advantageous for widespread applications, from biomedical research to drug manufacturing. Despite synthetic advances in bioorthogonal and photochemical methodologies, there is a need for generic chemical approaches that can universally modulate photodynamic reactivity in organic photosensitizers. Herein we present a strategy to fine-tune the production of singlet oxygen in multiple photosensitive scaffolds under the activation of bioresponsive and bioorthogonal stimuli. We demonstrate that the photocatalytic activity of nitrobenzoselenadiazoles can be fully blocked by site-selective incorporation of electron-withdrawing carbamate moieties and restored on demand upon uncaging with a wide range of molecular triggers, including abiotic transition-metal catalysts. We also prove that this strategy can be expanded to most photosensitizers, including diverse structures and spectral properties. Finally, we show that such advanced control of singlet oxygen generation can be broadly applied to the photodynamic ablation of human cells as well as to regulate the release of singlet oxygen in the semi-synthesis of natural product drugs.
Assuntos
Fármacos Fotossensibilizantes , Oxigênio Singlete , Oxigênio Singlete/química , Oxigênio Singlete/metabolismo , Fármacos Fotossensibilizantes/química , Fármacos Fotossensibilizantes/farmacologia , Humanos , Catálise/efeitos da radiação , Fotoquimioterapia/métodos , Carbamatos/química , Células HeLaRESUMO
Photodynamic therapy (PDT) is a promising alternative treatment for localized lesions and infections, utilizing reactive oxygen species (ROS) generated by photosensitizers (PS) upon light activation. Singlet oxygen (1O2) is a key ROS responsible for photodynamic damage. However, the effectiveness of PS in biological systems may not correlate with the efficiency of singlet oxygen generation in homogeneous solutions. This study investigated singlet oxygen generation and its decay in various cellular microenvironments using liposome and ARPE-19 cell models. Rose Bengal (RB), methylene blue (MB), and protoporphyrin IX (PpIX) were employed as selected PS. Lifetimes of singlet oxygen generated by the selected photosensitizers in different cellular compartments varied, indicating different quenching rates with singlet oxygen. RB, located near cell membranes, exhibited the highest phototoxicity and lipid/protein peroxidation, followed by PpIX, while MB showed minimal cytotoxicity in similar conditions. Singlet oxygen decay lifetimes provide insights into PS localization and potential phototoxicity, highlighting the importance of the lipid microenvironment in PDT efficacy, providing useful screening method prior to in vivo applications.
Assuntos
Lipossomos , Azul de Metileno , Fotoquimioterapia , Fármacos Fotossensibilizantes , Protoporfirinas , Rosa Bengala , Oxigênio Singlete , Oxigênio Singlete/metabolismo , Fármacos Fotossensibilizantes/farmacologia , Fármacos Fotossensibilizantes/química , Humanos , Rosa Bengala/farmacologia , Rosa Bengala/química , Protoporfirinas/química , Protoporfirinas/farmacologia , Protoporfirinas/metabolismo , Lipossomos/química , Azul de Metileno/química , Azul de Metileno/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Linhagem Celular , LuzRESUMO
Porphyrazines (Pzs) are porphyrin derivatives that show potential application as photosensitizers for photodynamic therapy (PDT), but are still far less explored in the literature. In this work, we evaluate how the photophysics and phototoxicity of the octakis(trifluoromethylphenyl)porphyrazine (H2Pz) against tumor cells can be modulated by coordination with Mg(II), Zn(II), Cu(II) and Co(II) ions. Fluorescence and singlet oxygen quantum yields for the Pzs were measured in organic solvents and in soy phosphatidylcholine (PC) liposomes suspended in water. While H2Pz and the respective complexes with Cu(II) and Co(II) showed very low efficiency to fluoresce and to produce 1O2, the Mg(II) and Zn(II) complexes showed significantly higher quantum yields in organic solvents. The fluorescence of these two Pzs in the liposomes was sensitive to the fluidity of the membrane, showing potential use as viscosity markers. The cytotoxicity of the compounds was tested in HaCaT (normal) and A431 (tumor) cells using soy PC liposomes as drug carriers. Despite the low 1O2 quantum yields in water, the Mg(II) and Zn(II) complexes showed IC50 values against A431 cells in the nanomolar range when activated with low doses of red LED light. Their phototoxicity was ca. three times higher for the tumor cells compared to the normal ones, showing promising application as photosensitizers for PDT protocols. Considering that H2Pz and the respective Co(II) and Cu(II) complexes were practically non-phototoxic to the cells, we demonstrate the importance of the central metal ion in the modulation of the photodynamic activity of porphyrazines.
Assuntos
Lipossomos , Fármacos Fotossensibilizantes , Porfirinas , Humanos , Fármacos Fotossensibilizantes/farmacologia , Fármacos Fotossensibilizantes/química , Porfirinas/química , Porfirinas/farmacologia , Lipossomos/química , Fotoquimioterapia , Oxigênio Singlete/metabolismo , Oxigênio Singlete/química , Complexos de Coordenação/farmacologia , Complexos de Coordenação/química , Complexos de Coordenação/síntese química , Antineoplásicos/farmacologia , Antineoplásicos/química , Antineoplásicos/síntese química , Zinco/química , Zinco/farmacologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Íons/químicaRESUMO
Peroxymonosulfate (PMS)-based advanced oxidation processes (AOPs), as a promising technology for water decontamination, are constrained by low reaction kinetics due to limited reaction selectivity and mass transfer. Herein, we designed a nanoconfined FeCo2O4-embedded ceramic membrane (FeCo2O4-CM) under flow-through pattern for PMS activation. Confining PMS and FeCo2O4 within nanochannels (3.0-4.7 nm) enhanced adsorption interactions (-7.84 eV vs -2.20 eV), thus boosting mass transfer. Nanoconfinement effect regulated electron transfer pathways from PMS to FeCo2O4-CM by modulating the active site transformation to ≡Co(III) in nanoconfined FeCo2O4-CM, enabling selectively generating 1O2. The primary role of 1O2 in the nanoconfined system was confirmed by kinetic solvent isotope experiments and indicative anthracene endoperoxide (DPAO2). The system enabled 100% removal of atrazine (ATZ) within a hydraulic retention time of 2.124 ms, demonstrating a rate constant over 5 orders of magnitude higher than the nonconfined system (3.50 × 103 s-1 vs 0.42 min-1). It also exhibited strong resilience to pH variations (3.3-9.0) and coexisting substances, demonstrating excellent stability indicated by consistent 100% ATZ removal for 14 days. This study sheds light on regulating electron transfer pathways to selectively generate 1O2 through the nanoconfinement effect, boosting the practical application of PMS-based AOPs in environmental remediation and potentially applying them to various other AOPs.
Assuntos
Cerâmica , Cerâmica/química , Oxigênio Singlete/química , Purificação da Água/métodos , Descontaminação/métodos , Oxirredução , Poluentes Químicos da Água/química , Cinética , Água/química , PeróxidosRESUMO
Naphthalocyanine-based agents exhibit huge potential in photodynamic therapy, yet their photodynamic performance is restricted by the penetration depth of the external laser. Herein, we employed 18F-FDG as an internal light source to excite silicon naphthalocyanine nanoparticles to simultaneously circumvent radiative transition and boost 1O2 generation for tumor suppression.
Assuntos
Nanopartículas , Fotoquimioterapia , Fármacos Fotossensibilizantes , Nanopartículas/química , Humanos , Fármacos Fotossensibilizantes/química , Fármacos Fotossensibilizantes/farmacologia , Fármacos Fotossensibilizantes/síntese química , Animais , Compostos Radiofarmacêuticos/química , Compostos Radiofarmacêuticos/farmacologia , Camundongos , Antineoplásicos/química , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Neoplasias/tratamento farmacológico , Neoplasias/diagnóstico por imagem , Oxigênio Singlete/metabolismo , Oxigênio Singlete/química , Silício/químicaRESUMO
Despite the prevalent of hexagonal, tetragonal, and triangular pore structures in two-dimensional covalent organic frameworks (2D COFs), the pentagonal pores remain conspicuously absent. We herein present the Cairo pentagonal tessellated COFs, achieved through precisely chosen geometry and metrics of the linkers, resulting in unprecedented mcm topology. In each pentagonal structure, porphyrin units create four uniform sides around 15.5 Å with 90° angles, while tetrabiphenyl unit establish a bottom edge about 11.6 Å with 120° angles, aligning precisely with the criteria of Cairo Pentagon. According to the narrow bandgap and strong near-infrared (NIR) absorbance, as-synthesized COFs exhibit the efficient singlet oxygen (1O2) generation and photothermal conversion, resulting in NIR photothermal combined photodynamic therapy to guide cancer cell apoptosis. Mechanistic studies reveal that the good 1O2 production capability upregulates intracellular lipid peroxidation, leading to glutathione depletion, low expression of glutathione peroxidase 4, and induction of ferroptosis. The implementation of pentagonal Cairo tessellations in this work provides a promising strategy for diversifying COFs with new topologies, along with multimodal NIR phototherapy.
Assuntos
Apoptose , Raios Infravermelhos , Fotoquimioterapia , Oxigênio Singlete , Humanos , Oxigênio Singlete/metabolismo , Oxigênio Singlete/química , Fotoquimioterapia/métodos , Estruturas Metalorgânicas/química , Porfirinas/química , Animais , Peroxidação de Lipídeos , Linhagem Celular Tumoral , Ferroptose , Fototerapia/métodos , Camundongos , Glutationa/química , Glutationa/metabolismo , Fármacos Fotossensibilizantes/química , Neoplasias/terapia , Neoplasias/metabolismoRESUMO
The rise of antimicrobial resistance poses a critical public health threat worldwide. While antimicrobial photodynamic therapy (aPDT) has demonstrated efficacy against multidrug-resistant (MDR) bacteria, its effectiveness can be limited by several factors, including the delivery of the photosensitizer (PS) to the site of interest and the development of bacterial resistance to PS uptake. There is a need for alternative methods, one of which is superhydrophobic antimicrobial photodynamic therapy (SH-aPDT), which we report here. SH-aPDT is a technique that isolates the PS on a superhydrophobic (SH) membrane, generating airborne singlet oxygen (1O2) that can diffuse up to 1 mm away from the membrane. In this study, we developed a SH polydimethylsiloxane dressing coated with PS verteporfin. These dressings contain air channels called a plastron for supplying oxygen for aPDT and are designed so that there is no direct contact of the PS with the tissue. Our investigation focuses on the efficacy of SH-aPDT on biofilms formed by drug-sensitive and MDR strains of Gram-positive (Staphylococcus aureus and S. aureus methicillin-resistant) and Gram-negative bacteria (Pseudomonas aeruginosa and P. aeruginosa carbapenem-resistant). SH-aPDT reduces bacterial biofilms by approximately 3 log with a concomitant decrease in their metabolism as measured by MTT. Additionally, the treatment disrupted extracellular polymeric substances, leading to a decrease in biomass and biofilm thickness. This innovative SH-aPDT approach holds great potential for combating antimicrobial resistance, offering an effective strategy to address the challenges posed by drug-resistant wound infections.
Assuntos
Antibacterianos , Biofilmes , Farmacorresistência Bacteriana Múltipla , Interações Hidrofóbicas e Hidrofílicas , Teste de Materiais , Testes de Sensibilidade Microbiana , Fotoquimioterapia , Fármacos Fotossensibilizantes , Oxigênio Singlete , Biofilmes/efeitos dos fármacos , Oxigênio Singlete/metabolismo , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Antibacterianos/farmacologia , Antibacterianos/química , Fármacos Fotossensibilizantes/farmacologia , Fármacos Fotossensibilizantes/química , Bandagens , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Tamanho da Partícula , Pseudomonas aeruginosa/efeitos dos fármacosRESUMO
Osmium(II) complexes have attractive properties for potential theranostic agents given their anticancer activitiy, their redox potentials favourable for biological transformations within cancer cells and their luminescence in the near infrared (NIR) region. To achieve localised detection and delivery, gold nanoparticles (AuNP) provide an attractive scaffold to attach multiple luminescent agents on a single particle and provide a multimodal platform for detection and loaclaised delivery. We have developed 13 nm and 25 nm AuNP decorated with an osmium complex based on 1,10-phenantholine and surface active bipyridine ligands, OsPhenSS for live cell imaging and singlet oxygen generation, notated as OsPhenSS·AuNP13 and OsPhenSS·AuNP25. The AuNP designs not only allow versatile modalities for localisation of the probe but also water solubility for the osmium metal complex. The osmium decorated nanoparticles OsPhenSS·AuNP13 and OsPhenSS·AuNP25 display characteristic NIR luminescence from the osmium(II) 3MLCT at 785 nm in aqueous solutions with visible excitation. Upon incubation of the nanoparticles in lung cancer and breast carcinoma the luminescence signature of osmium and the gold reflectance reveal localisation in the cytoplasmic and perinuclear compartments. Excitation of the nanoparticles at 552 nm in the presence of a ROS indicator revealed a marked increase in the green fluorescence from the indicator, consistent with photo-induced ROS generation. The detection of singlet oxygen by time-resolved luminescence studies of the osmium and the nanoparticle probes further demonstrates the dual activity of the osmium-based nanoprobes for imaging and therapy. The introduction of gold nanoparticles for carrying osmium imaging probes allows a novel versatile strategy combining detection and localised therapies at the nanoscale.
Assuntos
Ouro , Nanopartículas Metálicas , Osmio , Oxigênio Singlete , Ouro/química , Nanopartículas Metálicas/química , Osmio/química , Humanos , Oxigênio Singlete/metabolismo , Oxigênio Singlete/química , Linhagem Celular Tumoral , Células A549 , Neoplasias da Mama/diagnóstico por imagem , Neoplasias da Mama/metabolismoRESUMO
Green fluorescent protein (GFP) has opened vast new avenues in studies of live cells and is generally perceived as a benign, nontoxic and harmless fluorescent tag. We demonstrat that excited GFP is capable of inducing substantial DNA damage in cells expressing fusion proteins. In the presence of GFP, even low doses of blue light (12 µJ) induce single strand breaks (SSBs). When the fluorescence of GFP located in the cell nucleus or in the cytoplasm is excited by a much higher dose (17 mJ), DNA double-strand breaks (DSBs) are also induced. Such breaks are induced even when GFP is placed and illuminated in culture medium outside of living cells. We demonstrate that DNA damage is induced by singlet oxygen, which is generated by excited GFP. Although short exposures of live cells to exciting light typically used in fluorescence microscopy induce SSBs but carry little risk of inducing DNA double-strand breaks, larger doses, which may be used in FRAP, FLIM, FCS and super-resolution fluorescence microscopy studies, are capable of inducing not only numerous SSBs but also DSBs.
Assuntos
Quebras de DNA de Cadeia Dupla , Proteínas de Fluorescência Verde , Quebras de DNA de Cadeia Dupla/efeitos da radiação , Proteínas de Fluorescência Verde/metabolismo , Proteínas de Fluorescência Verde/química , Proteínas de Fluorescência Verde/genética , Humanos , Quebras de DNA de Cadeia Simples/efeitos da radiação , Oxigênio Singlete/metabolismo , Oxigênio Singlete/química , Luz , Microscopia de Fluorescência , AnimaisRESUMO
Antibacterial resistance causes around 1.27 million deaths annually around the globe and has been recognized as a top 3 priority health threat. Antimicrobial photodynamic therapy (aPDT) is considered a promising alternative to conventional antibiotic treatments. Algal lipid extracts have shown antibacterial effects when used as photosensitizers (PSs) in aPDT. In this work we assessed the photodynamic efficiency of lipidic extracts of microalgae belonging to different phyla (Bacillariophyta, Chlorophyta, Cyanobacteria, Haptophyta, Ochrophyta and Rhodophyta). All the extracts (at 1 mg mL-1) demonstrated a reduction of Staphylococcus aureus >3 log10 (CFU mL-1), exhibiting bactericidal activity. Bacillariophyta and Haptophyta extracts were the top-performing phyla against S. aureus, achieving a reduction >6 log10 (CFU mL-1) with light doses of 60 J cm-2 (Bacillariophyta) and 90 J cm-2 (Haptophyta). The photodynamic properties of the Bacillariophyta Phaeodactylum tricornutum and the Haptophyta Tisochrysis lutea, the best effective microalgae lipid extracts, were also assessed at lower concentrations (75 µg mL-1, 7.5 µg mL-1, and 3.75 µg mL-1), reaching, in general, inactivation rates higher than those obtained with the widely used PSs, such as Methylene Blue and Chlorine e6, at lower concentration and light dose. The presence of chlorophyll c, which can absorb a greater amount of energy than chlorophylls a and b; rich content of polyunsaturated fatty acids (PUFAs) and fucoxanthin, which can also produce ROS, e.g. singlet oxygen (1O2), when photo-energized; a lack of photoprotective carotenoids such as ß-carotene, and low content of tocopherol, were associated with the algal extracts with higher antimicrobial activity against S. aureus. The bactericidal activity exhibited by the extracts seems to result from the photooxidation of microalgae PUFAs by the 1O2 and/or other ROS produced by irradiated chlorophylls/carotenoids, which eventually led to bacterial lipid peroxidation and cell death, but further studies are needed to confirm this hypothesis. These results revealed the potential of an unexplored source of natural photosensitizers (microalgae lipid extracts) that can be used as PSs in aPDT as an alternative to conventional antibiotic treatments, and even to conventional PSs, to combat antibacterial resistance.
Assuntos
Lipídeos , Microalgas , Fotoquimioterapia , Fármacos Fotossensibilizantes , Staphylococcus aureus , Staphylococcus aureus/efeitos dos fármacos , Microalgas/química , Fármacos Fotossensibilizantes/farmacologia , Fármacos Fotossensibilizantes/química , Lipídeos/química , Xantofilas/farmacologia , Xantofilas/química , Luz , Clorofila/química , Clorofila/farmacologia , Antibacterianos/farmacologia , Antibacterianos/química , Diatomáceas/química , Haptófitas/química , Oxigênio Singlete/metabolismo , Testes de Sensibilidade Microbiana , Rodófitas/químicaRESUMO
The oxidation of proteins and, in particular, of tryptophan (Trp) residues leads to chemical modifications that can affect the structure and function. The oxidative damage to proteins in photochemical processes is relevant in the skin and eyes and is related to a series of pathologies triggered by exposure to electromagnetic radiation. In this work, we studied the photosensitized formation of N-formylkynurenine (NFKyn) from Trp in different reaction systems. We used two substrates: free Trp and a peptide of nine amino acid residues, with Trp being the only oxidizable residue. Two different photosensitizers were employed: Rose Bengal (RB) and pterin (Ptr). The former is a typical type II photosensitizer [acts by producing singlet oxygen (1O2)]. Ptr is the parent compound of oxidized or aromatic pterins, natural photosensitizers that accumulate in human skin under certain pathological conditions and act mainly through type I mechanisms (generation of radicals). Experimental data were collected in steady photolysis, and the irradiated solutions were analyzed by chromatography (HPLC). Results indicate that the reaction of Trp with 1O2 initiates the process leading to NFKyn, but different competitive pathways take place depending on the photosensitizer and the substrate. In Ptr-photosensitization, a type I mechanism is involved in secondary reactions accelerating the formation of NFKyn when free Trp is the substrate.
Assuntos
Cinurenina , Oxirredução , Fármacos Fotossensibilizantes , Rosa Bengala , Triptofano , Triptofano/química , Cinurenina/química , Cinurenina/análogos & derivados , Cinurenina/metabolismo , Fármacos Fotossensibilizantes/química , Rosa Bengala/química , Peptídeos/química , Oxigênio Singlete/química , Pterinas/química , Cromatografia Líquida de Alta Pressão , Fotólise , HumanosRESUMO
Molecular oxygen, O2, has long provided a cornerstone for studies in chemistry, physics, and biology. Although the triplet ground state, O2(X3Σg-), has garnered much attention, the lowest excited electronic state, O2(a1Δg), commonly called singlet oxygen, has attracted appreciable interest, principally because of its unique chemical reactivity in systems ranging from the Earth's atmosphere to biological cells. Because O2(a1Δg) can be produced and deactivated in processes that involve light, the photophysics of O2(a1Δg) are equally important. Moreover, pathways for O2(a1Δg) deactivation that regenerate O2(X3Σg-), which address fundamental principles unto themselves, kinetically compete with the chemical reactions of O2(a1Δg) and, thus, have practical significance. Due to technological advances (e.g., lasers, optical detectors, microscopes), data acquired in the past â¼20 years have increased our understanding of O2(a1Δg) photophysics appreciably and facilitated both spatial and temporal control over the behavior of O2(a1Δg). One goal of this Review is to summarize recent developments that have broad ramifications, focusing on systems in which oxygen forms a contact complex with an organic molecule M (e.g., a liquid solvent). An important concept is the role played by the M+â¢O2-⢠charge-transfer state in both the formation and deactivation of O2(a1Δg).
Assuntos
Oxigênio Singlete , Solventes , Oxigênio Singlete/química , Solventes/química , Animais , Humanos , Processos FotoquímicosRESUMO
Singlet oxygen generation has long been considered the key feature that allows genetically encoded fluorescent tags to produce polymeric contrast agents for electron microscopy. Optimization of the singlet oxygen sensitization quantum yield has not included the effects of electron-rich monomers on the sensitizer's photocycle. We report that at monomer concentrations employed for staining, quenching by electron transfer is the primary deactivation pathway for photoexcitations. A simple photochemical model including contributions from both processes reproduces the observed reaction rates and indicates that most of the product is driven by pathways that involve electron transfer with monomersânot by the sensitization of singlet oxygen. Realizing the importance of these competing reaction pathways offers a new paradigm to guide the development of genetically encodable tags and suggests opportunities to expand the materials scope and growth conditions for polymeric contrast agents (e.g., biocompatible monomers, O2 poor environments).