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BACKGROUND: HRASKO/NRASKO double knockout mice exhibit exceedingly high rates of perinatal lethality due to respiratory failure caused by a significant lung maturation delay. The few animals that reach adulthood have a normal lifespan, but present areas of atelectasis mixed with patches of emphysema and normal tissue in the lung. METHODS: Eight double knockout and eight control mice were analyzed using micro-X-ray computerized tomography and a Small Animal Physiological Monitoring system. Tissues and samples from these mice were analyzed using standard histological and Molecular Biology methods and the significance of the results analyzed using a Student´s T-test. RESULTS: The very few double knockout mice surviving up to adulthood display clear craniofacial abnormalities reminiscent of those seen in RASopathy mouse models, as well as thrombocytopenia, bleeding anomalies, and reduced platelet activation induced by thrombin. These surviving mice also present heart and spleen hyperplasia, and elevated numbers of myeloid-derived suppressor cells in the spleen. Mechanistically, we observed that these phenotypic alterations are accompanied by increased KRAS-GTP levels in heart, platelets and primary mouse embryonic fibroblasts from these animals. CONCLUSIONS: Our data uncovers a new, previously unidentified mechanism capable of triggering a RASopathy phenotype in mice as a result of the combined removal of HRAS and NRAS.
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GTP Fosfo-Hidrolases , Camundongos Knockout , Fenótipo , Proteínas Proto-Oncogênicas p21(ras) , Animais , Proteínas Proto-Oncogênicas p21(ras)/genética , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Camundongos , GTP Fosfo-Hidrolases/genética , GTP Fosfo-Hidrolases/metabolismo , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Ativação Plaquetária/genética , Baço/patologia , Baço/metabolismo , Proteínas Monoméricas de Ligação ao GTPRESUMO
INTRODUCTION: The development of second primary tumours (SPTs) is one of the main causes of low survival in patients with head and neck cancer (HNC). The aim of this study was to review the evidence about factors associated with developing SPTs in patients with HNC. METHODS: An updated systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, and the search was performed in Pubmed and Scopus. Only original articles with a cohort or case-control design were included. Article quality was assessed with the Newcastle-Ottawa scale. RESULTS: Thirty-six and two case-control studies were included, with quality medium (n = 5) to high (n = 33). Tobacco showed a significant association with SPT development, with risks ranging from 1.41 (95%CI: 1.04-1.91) to 5.52 (95%CI: 2.91-10.49). Regarding alcohol, risks ranged from 1.46 (95%CI: 1.12-1.91) to 21.3 (95%CI: 2.9-156). Location of the index tumour in the hypopharynx/oropharynx, absence of human papillomavirus and presence of a premalignant lesion also increased the risk of SPTs. More controversy was found for sex, age and other clinical factors of the tumour. CONCLUSION: Toxic lifestyle habits and clinical factors were associated with the risk of SPTs in HNC patients. These findings may improve individualised prevention strategies in its follow-up.
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Neoplasias de Cabeça e Pescoço , Segunda Neoplasia Primária , Humanos , Neoplasias de Cabeça e Pescoço/complicações , Estudos de Casos e ControlesRESUMO
The effects of surfactants of different nature (anionic, cationic and non-ionic) and chain length on the morphology, microstructure, thermal stability and electrical resistivity of liquid exfoliated graphene (G) were investigated. Microscopic (SEM and AFM) observations revealed that the thickness of G in the dispersions depended on the surfactant nature: non-ionic surfactants rendered the highest level of exfoliation, whilst dispersions in the cationic ones exhibited fully-covered thicker sheets; the flake thickness increased with increasing surfactant chain length. X-ray diffraction studies indicated an increased interlamellar G spacing with increasing surfactant content. Raman spectra showed an increase in the ID/IG ratio with decreasing G loading. Larger upshifts of the G, 2D and D + G bands were found with increasing surfactant concentration, particularly for dispersions in the cationic surfactants. For the same G/surfactant weight ratio, the electrical resistivity of the dispersions followed the order: cationic > non-ionic > anionic, consistent with the amount of surfactant adsorbed onto G calculated via TGA. It is demonstrated herein that the thermal and electrical properties of liquid exfoliated G can be tuned by varying the surfactant concentration, nature and chain length, which is of great importance for numerous applications like solar power harvesting, high-temperature devices and flexible nanoelectronics.
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Introduction: Exacerbations of chronic obstructive pulmonary disease (COPD) increase mortality risk and can lead to accelerated loss of lung function. The increased inflammatory response during exacerbations contributes to worsening of airflow limitation, but whether it also impacts epithelial repair is unclear. Therefore, we studied the effect of the soluble factor micro-environment during COPD exacerbations on epithelial repair using an exacerbation cocktail (EC), composed of four factors that are increased in COPD lungs during exacerbations (IL-1ß, IL-6, IL-8, TNF-α). Methods: Mouse organoids (primary CD31-CD45-Epcam+ cells co-cultured with CCL206 fibroblasts) were used to study epithelial progenitor behavior. Mature epithelial cell responses were evaluated using mouse precision cut lung slices (PCLS). The expression of epithelial supportive factors was assessed in CCL206 fibroblasts and primary human lung fibroblasts. Results: EC exposure increased the number and size of organoids formed, and upregulated Lamp3, Muc5ac and Muc5b expression in day 14 organoids. In PCLS, EC imparted no effect on epithelial marker expression. Pre-treatment of CCL206 fibroblasts with EC was sufficient to increase organoid formation. Additionally, the expression of Il33, Tgfa and Areg was increased in CCL206 fibroblasts from EC treated organoids, but these factors individually did not affect organoid formation or size. However, TGF-α downregulated Foxj1 expression and upregulated Aqp5 expression in day 14 organoids. Conclusions: EC exposure stimulates organoid formation and growth, but it alters epithelial differentiation. EC changes the epithelial progenitor support function of fibroblasts which contributes to observed effects on epithelial progenitors.
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Células Epiteliais , Fibroblastos , Organoides , Doença Pulmonar Obstrutiva Crônica , Animais , Doença Pulmonar Obstrutiva Crônica/metabolismo , Doença Pulmonar Obstrutiva Crônica/patologia , Doença Pulmonar Obstrutiva Crônica/imunologia , Humanos , Camundongos , Fibroblastos/metabolismo , Células Epiteliais/metabolismo , Citocinas/metabolismo , Pulmão/patologia , Pulmão/imunologia , Pulmão/metabolismo , Células Cultivadas , Progressão da Doença , Mucosa Respiratória/metabolismo , Mucosa Respiratória/imunologia , Mucosa Respiratória/patologia , Camundongos Endogâmicos C57BLRESUMO
During all the stages of lung development, the lung mesoderm (or mesenchyme) is closely related to the endoderm, and their cross-regulation promotes, controls, and drives all lung developmental processes. Generation of 3D organoids in vitro, RNA assays, and mitochondrial respiration studies are used to analyze lung development and regeneration to better understand the interactions between epithelium and mesenchyme, as well as for the study of redox alterations and the metabolic status of the cells. Moreover, to avoid using immortalized cell lines in these in vitro approaches, standardized murine neonatal primary lung fibroblast isolation techniques are essential. Here, we present an optimized method to isolate, culture, and freeze primary lung fibroblasts from neonatal lungs. Our current method includes step-by-step instructions accompanied by graphical explanations and critical steps.
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The impact of genetic ablation of SOS1 or SOS2 is evaluated in a murine model of KRASG12D-driven lung adenocarcinoma (LUAD). SOS2 ablation shows some protection during early stages but only SOS1 ablation causes significant, specific long term increase of survival/lifespan of the KRASG12D mice associated to markedly reduced tumor burden and reduced populations of cancer-associated fibroblasts, macrophages and T-lymphocytes in the lung tumor microenvironment (TME). SOS1 ablation also causes specific shrinkage and regression of LUAD tumoral masses and components of the TME in pre-established KRASG12D LUAD tumors. The critical requirement of SOS1 for KRASG12D-driven LUAD is further confirmed by means of intravenous tail injection of KRASG12D tumor cells into SOS1KO/KRASWT mice, or of SOS1-less, KRASG12D tumor cells into wildtype mice. In silico analyses of human lung cancer databases support also the dominant role of SOS1 regarding tumor development and survival in LUAD patients. Our data indicate that SOS1 is critically required for development of KRASG12D-driven LUAD and confirm the validity of this RAS-GEF activator as an actionable therapeutic target in KRAS mutant LUAD.
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Adenocarcinoma de Pulmão , Adenocarcinoma , Fibroblastos Associados a Câncer , Neoplasias Pulmonares , Animais , Humanos , Camundongos , Adenocarcinoma/genética , Adenocarcinoma de Pulmão/genética , Neoplasias Pulmonares/genética , Proteínas Proto-Oncogênicas p21(ras)/genética , Microambiente Tumoral/genéticaRESUMO
We showed previously that the ABL-mediated phosphorylation of SOS1 promotes RAC activation and contributes to BCR-ABL leukemogenesis, suggesting the relevant role of SOS1 in the pathogenesis of CML. To try and obtain direct experimental evidence of the specific mechanistic implication of SOS1 in CML development, here, we combined a murine model of CML driven by a p210BCR/ABL transgene with our tamoxifen-inducible SOS1/2-KO system in order to investigate the phenotypic impact of the direct genetic ablation of SOS1 or SOS2 on the pathogenesis of CML. Our observations showed that, in contrast to control animals expressing normal levels of SOS1 and SOS2 or to single SOS2-KO mice, p210BCR/ABL transgenic mice devoid of SOS1 presented significantly extended survival curves and also displayed an almost complete disappearance of the typical hematological alterations and splenomegaly constituting the hallmarks of CML. SOS1 ablation also resulted in a specific reduction in the proliferation and the total number of colony-forming units arising from the population of bone marrow stem/progenitor cells from p210BCR/ABL transgenic mice. The specific blockade of CML development caused by SOS1 ablation in p210BCR/ABL mice indicates that SOS1 is critically required for CML pathogenesis and supports the consideration of this cellular GEF as a novel, alternative bona fide therapeutic target for CML treatment in the clinic.
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Recent breakthroughs have reignited interest in RAS GEFs as direct therapeutic targets. To search for new inhibitors of SOS GEF activity, a repository of known/approved compounds (NIH-NACTS) and a library of new marine compounds (Biomar Microbial Technologies) were screened by means of in vitro RAS-GEF assays using purified, bacterially expressed SOS and RAS constructs. Interestingly, all inhibitors identified in our screenings (two per library) shared related chemical structures belonging to the anthraquinone family of compounds. All our anthraquinone SOS inhibitors were active against the three canonical RAS isoforms when tested in our SOS GEF assays, inhibited RAS activation in mouse embryonic fibroblasts, and were also able to inhibit the growth of different cancer cell lines harboring WT or mutant RAS genes. In contrast to the commercially available anthraquinone inhibitors, our new marine anthraquinone inhibitors did not show in vivo cardiotoxicity, thus providing a lead for future discovery of stronger, clinically useful anthraquinone SOS GEF blockers.
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Antraquinonas/farmacologia , Antineoplásicos/farmacologia , GTP Fosfo-Hidrolases/antagonistas & inibidores , Proteínas de Membrana/antagonistas & inibidores , Proteínas Proto-Oncogênicas p21(ras)/antagonistas & inibidores , Bibliotecas de Moléculas Pequenas/farmacologia , Animais , Cardiotoxicidade/prevenção & controle , Linhagem Celular Transformada , Linhagem Celular Tumoral , Doxorrubicina/farmacologia , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Células Epiteliais/patologia , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , GTP Fosfo-Hidrolases/genética , GTP Fosfo-Hidrolases/metabolismo , Humanos , Idarubicina/farmacologia , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Knockout , Proteínas Proto-Oncogênicas p21(ras)/genética , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Proteína SOS1/genética , Proteína SOS1/metabolismo , Proteínas Son Of Sevenless/deficiência , Proteínas Son Of Sevenless/genéticaRESUMO
Prior reports showed the critical requirement of Sos1 for epithelial carcinogenesis, but the specific functionalities of the homologous Sos1 and Sos2 GEFs in skin homeostasis and tumorigenesis remain unclear. Here, we characterize specific mechanistic roles played by Sos1 or Sos2 in primary mouse keratinocytes (a prevalent skin cell lineage) under different experimental conditions. Functional analyses of actively growing primary keratinocytes of relevant genotypes-WT, Sos1-KO, Sos2-KO, and Sos1/2-DKO-revealed a prevalent role of Sos1 regarding transcriptional regulation and control of RAS activation and mechanistic overlapping of Sos1 and Sos2 regarding cell proliferation and survival, with dominant contribution of Sos1 to the RAS-ERK axis and Sos2 to the RAS-PI3K/AKT axis. Sos1/2-DKO keratinocytes could not grow under 3D culture conditions, but single Sos1-KO and Sos2-KO keratinocytes were able to form pseudoepidermis structures that showed disorganized layer structure, reduced proliferation, and increased apoptosis in comparison with WT 3D cultures. Remarkably, analysis of the skin of both newborn and adult Sos2-KO mice uncovered a significant reduction of the population of stem cells located in hair follicles. These data confirm that Sos1 and Sos2 play specific, cell-autonomous functions in primary keratinocytes and reveal a novel, essential role of Sos2 in control of epidermal stem cell homeostasis.
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The decision on the fitness of a measurement for its intended use and the interpretation of an analytical result requires the assessment of the measurement uncertainty. Frequently, the determination of analytes in complex matrices involves demanding sample preparations in which analyte losses are observed. These losses should be considered when reporting the results, which can be corrected for low recovery by taking the mean recovery observed in the analysis of reference items (e.g. spiked samples) or, alternatively, by subjecting calibrators to the same pre-treatment performed on the samples. In these cases, neat (NC) or adjusted (AC) calibrators are used, respectively. The way analyte losses are handled impacts on the measurement uncertainty. The top-down evaluation of the measurement uncertainty involves combining precision, trueness and additional uncertainty components. The trueness component is quantified by pooling various analyte recovery determinations. This work assesses and compares the uncertainty of polycyclic aromatic hydrocarbons (PAHs) measurements in water based on HPLC-FD calibrations with NC or AC. The trueness component is estimated by pooling mean recoveries observed from the analysis of different spiked samples to which mean recovery uncertainty and degrees of freedom are used to estimate a weighted mean recovery and respective uncertainty. The performance of measurements based on NC and AC are associated with equivalent uncertainty except when large analyte losses are observed, namely in the determination of Naphtalene. In this case, the processing of AC reduces the expanded relative uncertainty from 9.9% to 3.5%. The evaluated expanded uncertainty ranged from 3.5% to 12% of the measured value.
Assuntos
Métodos Analíticos de Preparação de Amostras/métodos , Hidrocarbonetos Policíclicos Aromáticos/análise , Incerteza , Água/química , Calibragem , Cromatografia Líquida de Alta Pressão , Reprodutibilidade dos TestesRESUMO
Different graphene/sepiolite (G/Sep) solid mixtures have been prepared and tested as nanometric sorbents for the analysis of polycyclic aromatic hydrocarbons (PAHs) using dispersive solid phase extraction (dSPE) and aqueous solutions of surfactants as environmentally friendly agents for desorption. Quantification of the PAHs was carried out by reversed-phase liquid chromatography (RP-HPLC) with fluorescence detection. The adsorption of four PAHs with increasing number of benzene rings into a G/Sep mixture (2/98, w/w) was investigated. A 100% retention was attained for phenanthrene (Phe), pyrene (Pyr) and benzo(a)pyrene (BaP), while for naphthalene (Nap) the maximum retention was close to 75%. The G/Sep mixtures can be used to remove the PAHs from wastewater. The desorption step was carried out using an aqueous surfactant solution: 100 mM non-ionic polyoxiethylen-23-lauryl eter (Brij L23). Considering the whole extraction process, the highest PAH recoveries (50, 92, 83 and 76% for Nap, Phe, Pyr and BaP, respectively) were obtained using 100 mM Brij L23. The developed method shows very high sensitivity, robustness and precision, as well as low limits of detection and quantification, and has been successfully applied to the analysis of PAHs in wastewater samples.
Assuntos
Técnicas de Química Analítica/métodos , Grafite/química , Silicatos de Magnésio/química , Hidrocarbonetos Policíclicos Aromáticos/análise , Extração em Fase Sólida , Águas Residuárias/química , Adsorção , Tensoativos/químicaRESUMO
We reported previously that adult (HRAS-/-; NRAS-/-) double knockout (DKO) mice showed no obvious external phenotype although lower-than-expected numbers of weaned DKO animals were consistently tallied after crossing NRAS-KO and HRAS-KO mice kept on mixed genetic backgrounds. Using mouse strains kept on pure C57Bl/6 background, here we performed an extensive analysis of the offspring from crosses between HRAS-KO and NRAS-KO mice and uncovered the occurrence of very high rates of perinatal mortality of the resulting DKO littermates due to respiratory failure during the first postnatal 24-48 h. The lungs of newborn DKO mice showed normal organ structure and branching but displayed marked defects of maturation including much-reduced alveolar space with thick separating septa and significant alterations of differentiation of alveolar (AT1, AT2 pneumocytes) and bronchiolar (ciliated, Clara cells) cell lineages. We also observed the retention of significantly increased numbers of undifferentiated progenitor precursor cells in distal lung epithelia and the presence of substantial accumulations of periodic acid-Schiff-positive (PAS+) material and ceramide in the lung airways of newborn DKO mice. Interestingly, antenatal dexamethasone treatment partially mitigated the defective lung maturation phenotypes and extended the lifespan of the DKO animals up to 6 days, but was not sufficient to abrogate lethality in these mice. RNA microarray hybridization analyses of the lungs of dexamethasone-treated and untreated mice uncovered transcriptional changes pointing to functional and metabolic alterations that may be mechanistically relevant for the defective lung phenotypes observed in DKO mice. Our data suggest that delayed alveolar differentiation, altered sphingolipid metabolism and ceramide accumulation are primary contributors to the respiratory stress and neonatal lethality shown by DKO mice and uncover specific, critical roles of HRAS and NRAS for correct lung differentiation that are essential for neonatal survival and cannot be substituted by the remaining KRAS function in this organ.
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Brônquios , Diferenciação Celular , Proteínas Monoméricas de Ligação ao GTP/deficiência , Proteínas Proto-Oncogênicas p21(ras)/deficiência , Alvéolos Pulmonares , Insuficiência Respiratória , Animais , Brônquios/crescimento & desenvolvimento , Brônquios/patologia , Camundongos , Camundongos Knockout , Proteínas Monoméricas de Ligação ao GTP/metabolismo , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Alvéolos Pulmonares/crescimento & desenvolvimento , Alvéolos Pulmonares/patologia , Insuficiência Respiratória/genética , Insuficiência Respiratória/metabolismo , Insuficiência Respiratória/patologiaRESUMO
The influence of graphene (G) dispersions in different types of surfactants (anionic, non-ionic, and cationic) on the fluorescence of vitamin B6 (pyridoxine) was studied. Scanning electron microscopy (SEM) was used to evaluate the quality of the G dispersions via measuring their flake thickness. The effect of surfactant type and concentration on the fluorescence intensity was analyzed, and fluorescence quenching effects were found for all of the systems. These turn out to be more intense with increasing both surfactant and G concentrations, albeit they do not depend on the G/surfactant weight ratio. For the same G concentration, the magnitude of the quenching follows the order: cationic > non-ionic ≥ anionic. The cationic surfactants, which strongly adsorb onto G via electrostatic attraction, are the most effective dispersing agents and they enable a stronger interaction with the zwitterionic form of the vitamin; the dispersing power improves with increasing the surfactant chain length. The fit of the experimental data to the Stern-Volmer equation suggests either a static or dynamic quenching mechanism for the dispersions in non-ionic surfactants, while those in ionic surfactants show a combined mechanism. The results that were obtained herein have been compared to those that were reported earlier for the quenching of another vitamin, riboflavin, to elucidate how the change in the vitamin structure influences the interactions with G in the surfactant dispersions.
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Using Sos1 knockout (Sos1-KO), Sos2-KO, and Sos1/2 double-knockout (Sos1/2-DKO) mice, we assessed the functional role of Sos1 and Sos2 in skin homeostasis under physiological and/or pathological conditions. Sos1 depletion resulted in significant alterations of skin homeostasis, including reduced keratinocyte proliferation, altered hair follicle and blood vessel integrity in dermis, and reduced adipose tissue in hypodermis. These defects worsened significantly when both Sos1 and Sos2 were absent. Simultaneous Sos1/2 disruption led to severe impairment of the ability to repair skin wounds, as well as to almost complete ablation of the neutrophil-mediated inflammatory response in the injury site. Furthermore, Sos1 disruption delayed the onset of tumor initiation, decreased tumor growth, and prevented malignant progression of papillomas in a DMBA (7,12-dimethylbenz[α]anthracene)/TPA (12-O-tetradecanoylphorbol-13-acetate)-induced skin carcinogenesis model. Finally, Sos1 depletion in preexisting chemically induced papillomas resulted also in decreased tumor growth, probably linked to significantly reduced underlying keratinocyte proliferation. Our data unveil novel, distinctive mechanistic roles of Sos 1 and Sos2 in physiological control of skin homeostasis and wound repair, as well as in pathological development of chemically induced skin tumors. These observations underscore the essential role of Sos proteins in cellular proliferation and migration and support the consideration of these RasGEFs as potential biomarkers/therapy targets in Ras-driven epidermal tumors.
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Proteína SOS1/metabolismo , Neoplasias Cutâneas/etiologia , Pele/metabolismo , Proteínas Son Of Sevenless/metabolismo , Animais , Carcinogênese , Movimento Celular , Proliferação de Células , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/metabolismo , Transformação Celular Neoplásica/patologia , Homeostase , Camundongos , Camundongos Knockout , Neovascularização Fisiológica , Papiloma/metabolismo , Papiloma/patologia , Proteína SOS1/deficiência , Proteína SOS1/genética , Pele/irrigação sanguínea , Pele/citologia , Neoplasias Cutâneas/metabolismo , Neoplasias Cutâneas/patologia , Proteínas Son Of Sevenless/deficiência , Proteínas Son Of Sevenless/genética , CicatrizaçãoRESUMO
Fluorescence quenching is a valuable tool to gain insight about dynamic changes of fluorophores in complex systems. Graphene (G), a single-layered 2D nanomaterial with unique properties, was dispersed in surfactant aqueous solutions of different nature: non-ionic polyoxyethylene-23-lauryl ether (Brij L23), anionic sodium dodecylsulphate (SDS), and cationic hexadecyltrimethylammonium bromide (CTAB) and dodecyltrimethylammonium bromide (DTAB). The influence of the surfactant type, chain length and concentration, G total concentration and G/surfactant weight ratio on the fluorescence intensity of vitamin B2 (riboflavin) was investigated. The quality of the different G dispersions was assessed by scanning and transmission electron microscopies (SEM and TEM). A quenching phenomenon of the fluorescence of riboflavin was found for G dispersions in all the surfactants, which generally becomes stronger with increasing G/surfactant weight ratio. For dispersions in the ionic surfactants, the quenching is more pronounced as the surfactant concentration raises, whilst the non-ionic one remains merely unchanged for the different G/Brij L23 weight ratios. More importantly, results indicate that DTAB solutions are the optimum media for dispersing G sheets, leading to an up to 16-fold drop in the fluorescence intensity. Understanding the mechanism in fluorescence quenching of G dispersions in surfactants could be useful for several optical applications.