Avaliar in vivo o efeito da Terapia Fotodinâmica Antimicrobiana (aPDT), após tratamento endodôntico em sessão única, em dentes de cães com lesão periapical, em comparação ao tratamento em duas sessões com o uso de curativo de demora à base de hidróxido de cálcio. Material e Métodos: Após a indução experimental da lesão periapical e instrumentação dos canais radiculares, 48 dentes foram distribuídos nos seguintes grupos: I e III Uso de curativo de demora com pasta à base de hidróxido de cálcio (Calen®); e II e IV -Tratamento em uma única sessão com utilização da aPDT. Os canais radiculares foram obturados e decorridos os períodos experimentais de 120 dias (Grupos I e II) e 180 dias (Grupos III e IV), os animais foram submetidos à eutanásia. Após processamento histotécnico, análise microscópica descritiva/semi-quantitativa, avaliação morfométrica do tamanho da lesão periapical em microscopia de fluorescência e análise radiográfica foram realizadas. Foram utilizados os testes de Kruskal Wallis e exato de Fisher (=0,05). Resultados: Na análise microscópica descritiva, os grupos I e III apresentaram áreas cementárias reparadas, com numerosos feixes colágenos no ligamento periodontal e presença suave de células inflamatórias. Nos grupos II e IV as áreas de reabsorção cementária não estavam reparadas, com reduzida presença de células e fibras e presença de células inflamatórias. Na análise semi-quantitativa do selamento biológico apical houve diferença significante (p<0,0001) entre os grupos I e II; e entre os grupos III e IV (p<0,0001). A análise em microscopia de fluorescência evidenciou diferença significante entre os grupos, após 120 dias (p=0,0004) e após 180 dias (p=0,0081), sendo que os grupos I e III apresentaram lesões periapicais menores. A porcentagem de redução radiográfica das lesões evidenciou diferença significante entre os grupos (p<0,05), com maior porcentagem de redução para os grupos I e III. Com relação à análise imunohistoquímica, nos grupos I, II e IV, as marcações para RANK, RANKL e OPG indicaram sinalização pró-reabsortiva, embora a marcação para RANKL no grupo I tenha sido pouco intensa. Já no grupo III, as marcações evidenciaram ocorrência de neoformação óssea. Conclusão: O tratamento em duas sessões com o uso de curativo de demora à base de hidróxido de cálcio promoveu maior redução no tamanho das lesões periapicais e estágio mais avançado de reparo, evidenciado pelos melhores resultados histopatológicos, imunohistoquímicos e radiográficos, em comparação ao tratamento em uma única sessão com utilização do protocolo de aPDT avaliado. / To evaluate one-session endodontic treatment with aPDT and two-session treatment with calcium-hydroxide (CH)-based dressing in dog\'s teeth with apical periodontitis. Methods: After experimental induction of apical periodontitis, 48 teeth were randomly assigned to the following groups: Group I (one-session treatment with aPDT 120 days); Group II (one-session treatment with aPDT 180 days); Group III (two-session treatment with CH-based dressing -120 days) and Group IV (two-session treatment with CH-based dressing -180 days). The animals were euthanized after 120 and 180 days. After histotechnical processing, microscopic and radiographic analyses were performed. Data were analyzed by Kruskal-Wallis and Fishers exact tests (=0.05). Results: In the microscopical analysis, Groups I and III presented repaired cemental areas, with various colagen bundles in the periodontal ligament and mild presence of inflamatory cells. In the groups III and IV the present resorbed cemental areas were not repired, with reduced number of cells and fibers and the presence of inflamatory cells. The semi-quantitative analysis of the apical clousure, there was a significant difference (p<0.0001) between groups I and II; and between groups III and IV (p<0.0001). In the fluorescence microscopy analysis, there was a significant difference between groups, aftter 120 days (p=0.0004) and after 180 days (p=0.0081). The groups I and III presented smaller periapical lesions. The percentage of radiographic reduction of lesions demonstrated a significant difference between groups (p<0.05) with a higher reducton in group I and II. Regarding the immunohistochemistry analysis, in the groups I, II and IV, RANK, RANKL and OPG staining indicated pro-resorption signaling; although the RANKL immunostaining in the group I were not intense. In the group III, the immunostaining demonstrated the occurrence of bone neoformation. Conclusion: Two-session treatment with CH based promoted more reduction in the periapical lesion size and more repair advanced stage, highlighting better histopathological, immunostaining and radiographic results in comparison with one-session treatment with aPDT protocol used.

A poiquilodermia de Civatte (PC) é uma alteração dermatológica caracterizada por atrofia, pigmentação macular ou reticulada e telangiectasias na face, pescoço e tórax anterior. Várias tentativas de tratamentos não foram bem sucedidas por se mostrarem ineficazes e/ou com efeitos colaterais indesejáveis. Estudos clínicos mostram bons resultados clínicos no tratamento da PC com luz intensa pulsada (LIP). A terapia fotodinâmica (TFD) é uma modalidade terapêutica que envolve a administração tópica de um composto fotossensibilizante seguido de irradiação seletiva da lesão com luz visível. O propósito deste trabalho consiste na avaliação clínica e histopatológica da pele com PC, no tórax anterior, em 12 pacientes do sexo feminino, antes e após o tratamento com a TFD. Foram realizadas 3 sessões de tratamento com intervalos de 30 dias entre as sessões. A TFD foi realizada com a utilização prévia de cloridrato de aminolevulinato de metila 16% em creme (Metivix) 1h e 30min (oclusivo) antes da aplicação da LIP (Lime light). A avaliação clínica mostrou melhora em 84,6% no componente vascular, 80,8% no componente melanodérmico, 82,9% na textura, 77,1% nas rítides e 58,3% na flacidez de pele. Na histopatologia notou-se após o tratamento aumento estatisticamente significativo da espessura epidérmica, diminuição estatisticamente significativa do pigmento melânico e da área dos vasos marcados pelo fator VIII. Não houve nenhum efeito colateral permanente, mostrando que a TFD-MAL é uma nova opção terapêutica segura e eficaz para o tratamento da PC no tórax anterior / Poikiloderma of Civatte (PC) is the dermatological modification characterized by atrophy, macular or reticulate pigmentation and telangiectasias on the face, neck and anterior thorax. Several treatment attempts were unsuccessful, revealing to be ineffective and/or causing adverse effects. Clinical studies indicate good clinical results in the treatment of poikiloderma of Civatte with intense pulsed light (IPL). Photodynamic Therapy (PDT) is a therapeutic modality that involves the topical administration of a photosensitizing compound, followed by a selective irradiation of the lesion with visible light. The objective of this study consisted in the clinical and histopathologic evaluations of the skin with poikiloderma of Civatte (PC) on the anterior thorax of 12 female patients, before and after being treated with photodynamic therapy (PDT). Three treatment sessions were given at 30-day intervals. Photodynamic therapy was performed with methyl aminolevulinate hydrochloride 16% (Metivix) cream applied 1h and 30min under occlusion prior to LIP (Lime light) exposure. The clinical evaluation indicated an 84.6% improvement of vascular component, 80.8% of melanodermic component, 82.9% of texture, 77.1% of wrinkles and 58.3% of skin laxity. In the histopathology, a statistically significant increase of epidermal thickness was observed after the treatment, as well as a statistically significant reduction in the number of melanin pigment and of blood vessels area marked for Factor VIII. There were no permanent side effects, showing that the PDT-MAL is a new, safe and effective technic for treating PC on the anterior thorax

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-04-01T14:52:45Z No. of bitstreams: 1 cristianeferreiraalfenas.pdf: 2237269 bytes, checksum: de6cc845b64194029dea071db9814d80 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-04-24T03:17:20Z (GMT) No. of bitstreams: 1 cristianeferreiraalfenas.pdf: 2237269 bytes, checksum: de6cc845b64194029dea071db9814d80 (MD5) / Made available in DSpace on 2016-04-24T03:17:20Z (GMT). No. of bitstreams: 1 cristianeferreiraalfenas.pdf: 2237269 bytes, checksum: de6cc845b64194029dea071db9814d80 (MD5) Previous issue date: 2012-03-22 / O propósito do presente estudo foi avaliar, in vitro, a atividade antimicrobiana da Terapia Fotodinâmica (PDT) no sistema de canais radiculares, utilizando diferentes concentrações do fotossensibilizante azul de toluidina e doses do laser, sobre biofilme de Enterococcus faecalis, ATCC 51299. Foram utilizados 42 dentes extraídos de humanos, unirradiculares e os canais foram devidamente preparados, instrumentados pela técnica de instrumentação rotatória. Os dentes foram autoclavados e os canais inoculados com uma suspensão conhecida de Enterococcus faecalis foram incubados por 21 dias. Os espécimes submetidos à PDT, utilizando combinações com diferentes concentrações do fotossensibilizante azul de toluidina (TBO) (0.5, 5 e 10μg/ml) e tempos de irradiação (60, 120, 300 e 600s) equivalentes a doses de energia 6, 12, 30 e 60J, utilizando uma fibra óptica intracanal e irradiação com o laser de diodo (AsGaAl) a 100mW. Os controles, positivo e negativo, não receberam nenhum tipo de tratamento. Amostras do conteúdo intracanal foram coletadas com cone de papel esterilizado, antes e após os respectivos tratamentos e submetidos à cultura contendo ágar BHI. Para determinar o número de unidades formadoras de colônias por mL (UFC/mL). Os dados obtidos na análise microbiológica (UFC/mL) foram analisados por meio da análise de variância e teste de Tukey. E para confirmar a formação de biofilme, dois espécimes de cada grupo foram selecionados e analisados ao microscópio eletrônico de varredura (MEV). As combinações de TBO 0.5μg/ml e 600s e 5μg/ml e 10μg/ml em todos os tempos de irradiação testados resultaram em significativa redução dos micro-organismos, sendo que a combinação TBO 5μg/ml e 600s apresentou significantemente a maior porcentagem de redução. Foi possível concluir que a utilização da PDT com o fotossensibilizante TBO e irradiação com laser de baixa potência apresenta ação antibacteriana significativa sobre biofilme de Enterococcus faecalis, sendo uma terapia promissora frente aos micro-organismos persistentes ao tratamento endodôntico convencional. / The purpose of this study was to evaluate in vitro antimicrobial activity of Photodynamic Therapy (PDT) in the root canal system, using different concentrations of photosensitizer toluidine blue (TBO) and laser doses on biofilms of Enterococcus faecalis, ATCC 51299. Used 42 extracted human teeth, single-rooted and the canals prepared to rotary instrumentation. The teeth were autoclaved and canals inoculated with a suspension Enterococcus faecalis in brain heart infusion and were incubated for 21 days. The specimens were subjected to PDT using combinations with different concentrations of the photosensitizer TBO (0.5, 5 and 10μg/ml) and irradiation times (60, 120, 300 and 600s) equivalent to doses of energy 6, 12, 30 and 60J, using an optical fiber intracanal and irradiation with diode laser (GaAlAs) to 100mW. The controls groups no treatment. Before and after the respective treatments the canal contents were sampled with sterilized paper points, the sample was dispersed in transport medium, serially diluted and culture on blood agar to determine the number of colony forming units per mL (CFU / mL). The data obtained in the microbiological analysis (CFU / mL) were analyzed by analysis of variance and Tukey test. And to confirm biofilm formation, two specimens of each group were selected and analyzed by scanning electron microscopy (SEM). Combinations of TBO 0.5μg/ml and 600s and TBO 5μg/ml, 10μg/ml and in all irradiation times tested resulted in significant reduction of micro-organisms but the combination TBO 5μg/ml and 600s showed significantly higher percentage of reduction. It was concluded that the use of PDT with the photosensitizer TBO and laser irradiation low power presents significant antibacterial action on biofilm of Enterococcus faecalis, is a promising therapy in the face of persistent micro-organisms to conventional endodontic treatment.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-04-08T19:04:51Z No. of bitstreams: 1 marianeflorianolopessantoslacerda.pdf: 1354774 bytes, checksum: 55f105b0766962bb875bd589c83403bf (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-04-24T03:38:57Z (GMT) No. of bitstreams: 1 marianeflorianolopessantoslacerda.pdf: 1354774 bytes, checksum: 55f105b0766962bb875bd589c83403bf (MD5) / Made available in DSpace on 2016-04-24T03:38:57Z (GMT). No. of bitstreams: 1 marianeflorianolopessantoslacerda.pdf: 1354774 bytes, checksum: 55f105b0766962bb875bd589c83403bf (MD5) Previous issue date: 2013-04-30 / FAPEMIG - Fundação de Amparo à Pesquisa do Estado de Minas Gerais / A PDT antimicrobiana é um eficiente método coadjuvante na desinfecção do sistema de canais radiculares, o que torna importante o estudo sobre a possibilidade de alterações morfológicas e permeabilidade provocadas pelo laser de diodo na estrutura dentinária radicular. A proposta deste estudo foi investigar as alterações morfológicas e percentual de infiltração apical radicular após o uso do laser diodo. Quarenta dentes monorradiculares foram instrumentados pelo sistema rotatório Protaper e irrigados com NaOCl 5,25% e EDTA 17%. Depois, foram divididos aleatoriamente em: G1: não receberam PDT (controle); G2: receberam pré-irradiação com fotossensibilizador azul de toluidina e irradiação com laser diodo de AsGaAl. Em seguida, 10 dentes de cada grupo foram analisados por MEV quanto as alterações morfológicas. Os outros 10 dentes foram obturados e corados por Rodamina B para avaliar o percentual de infiltração apical. Os resultados mostraram diferença significativa entre G1 e G2 (p<0,001 - qui-quadrado), verificando maior presença de debris em G1 (controle) e maior ocorrência de túbulos dentinários abertos em G2 (PDT). Erosões e cracks foram observadas em ambos os grupos, sem diferença estatística significativa (p>0,001). O percentual de infiltração apical foi significativamente maior em G2 que em G1 (p<0,001 – t student). Concluiu-se que a utilização do laser diodo promoveu a redução de smear layer e abertura dos túbulos dentinários, não influenciando na ocorrência de erosão, cracks e carbonização. O laser aumentou a permeabilidade da dentina apical. / The antimicrobial PDT is an eficient method supporting the disinfection of the root canal system, which makes it important to study on the possibility of morphological and permeability caused by the diode laser on the root dentin structure. The purpose of this study was to investigate the morphological and percentage of root apical leakage after using the diode laser. Forty single teeth were instrumented by Protaper rotary system and irrigated with 5.25% NaOCl and 17% EDTA. They were then randomly divided into: G1 not receive PDT (control), G2: received pre-irradiation with toluidine blue photosensitizer and irradiation by GaAlAs laser diode. Then, ten teeth in each group were analyzed by SEM as morphological changes. The other ten teeth were filled and stained with Rhodamine B to evaluate the percentage of apical leakage. The results showed significant difference between G1 and G2 (p <0.001 - chi-square), checking greater presence of debris in G1 (control) and higher incidence of open dentinal tubules in G2 (PDT). Erosions and cracks were observed in both groups, with no statistically significant difference (p> 0.001). The percentage of apical leakage was significantly higher in G2 than in G1 (p <0.001 - t student). It was concluded that the use of the diode laser caused a reduction of smear layer and opening the dentinal tubules and does not influence the occurrence of erosion, cracks and carbonization. The laser increased the permeability of the apical dentine.

Submitted by Geandra Rodrigues (geandrar@gmail.com) on 2018-05-04T14:16:02Z No. of bitstreams: 0 / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2018-05-07T15:15:23Z (GMT) No. of bitstreams: 0 / Made available in DSpace on 2018-05-07T15:15:24Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-02-18 / A Laserterapia de Baixa Potência (Low Level Laser Therapy – LLLT) apresenta-se como uma terapia não invasiva reconhecida por acelerar processos reparativos tanto de tecidos moles quanto de tecidos duros devido aos seus efeitos biomoduladores nas células e nos tecidos. Quando há associação de uma fonte de luz de comprimento de onda conhecido a um corante fotossensível de baixa toxicidade, temos a, também conhecida, Terapia Fotodinâmica (Photodynamic Therapy - PDT) que, ainda pouco se sabe sobre sua ação no processo de consolidação óssea. O objetivo deste trabalho foi avaliar o processo de reparo ósseo em ratos submetidos à LLLT associada ou não ao azul de metileno a 0,01%, utilizando-se para isso a avaliação radiográfica e histológica. Defeitos ósseos foram realizados e distribuídos em quatro grupos: não tratados (Grupo controle); preenchidos por azul de metileno e não tratados (Grupo azul de metileno); tratados com laser 660nm (Grupo LLLT); preenchidos por azul de metileno e tratados com laser 660nm (Grupo LLLT + PDT). As radiografias foram realizadas nos dias 0, 7 e 14. Metade dos animais, irradiados ou não, foram eutanasiados após sete dias e a outra metade após 14 dias, sendo os fêmures removidos para análise histológica. Os resultados sugerem que, radiograficamente não houve consolidação óssea em nenhum dos grupos tratados, porém os defeitos ósseos do grupo LLLT + PDT apresentaram maior grau de radiopacidade; histologicamente houve maior aumento da área de neoformação óssea nos grupos LLLT e LLLT + PDT, com destaque para este último em ambos os períodos avaliados. Podemos desta forma, concluir que além da associação da PDT à LLLT ter sido eficaz, a combinação das duas técnicas promoveu indução da osteogênese de maneira precoce. / Low Level Laser Therapy (LLLT) is a recognized noninvasive therapy for accelerating repair processes of both soft and hard tissues due to their biomodulating effects on cells and tissues. When there is an association of a light source of known wavelength with a low toxicity photosensitive dye, we also have the known Photodynamic Therapy (PDT), which is still little known about its action in the process of bone healing. The objective of this work was to evaluate the bone repair process in rats submitted to LLLT, associated or not with 0.01% methylene blue, using radiographic and histological evaluation. Bone defects were performed and distributed in five groups: untreated (control group); filled with methylene blue and untreated (methylene blue group); treated with laser 660nm (LLLT Group); filled with methylene blue and treated with laser 660nm (LLLT + PDT Group). Radiographs were performed on days 0, 7 and 14. Half of the animals, irradiated or not, were euthanized after seven days and the other half after 14 days, and the femurs were removed for histological analysis. The results suggest that radiographically there was no bone consolidation in any of the treated groups, but the bone defects of the LLLT + PDT group presented a higher degree of radiopacity; histologically, there was a greater increase in the area of bone neoformation in the LLLT and LLLT + PDT groups, especially in the two evaluated periods. We can therefore conclude that besides the association of PDT with LLLT was effective, the combination of the two techniques promoted the induction of osteogenesis in an early manner.

Le cancer de la prostate est le cancer le plus fréquemment diagnostiqué chez l’homme de plus de 50 ans dans les pays industrialisés. L’importance accordée à la qualité de vie des patients conduit la recherche médicale à développer des méthodes de thérapie focale afin de traiter ce type de cancer de manière conservatrice et non plus de manière radicale. Dans cette optique, la photothérapie dynamique (PDT) repose sur l’utilisation de photosensibilisateurs (PS) capables de cibler spécifiquement les cellules cancéreuses et qui, une fois activés par la lumière, vont induire la mort de ces cellules. Sur la base de la chimie verte, le Laboratoire de Chimie des Substances Naturelles (LCSN) de Limoges a développé une stratégie de couplage de la protoporphyrine IX (PpIX), un PS largement étudié, avec des polyamines (PA). Les effets de ces nouveaux PS [la protoporphyrine IX dispermidinée (PpIX-dSd) et la protoporphyrine IX disperminée (PpIX-dSm)] ont été étudiés sur les cellules cancéreuses prostatiques humaines PC-3, DU 145 et LNCaP. Ce travail a permis de démontrer que ces deux PS répondent aux critères attendus d’un PS : une composition pure, une absence de toxicité en absence de lumière et une sélectivité vis-à-vis des cellules tumorales. De plus, ces PS induisent l’apoptose de ces cellules via la voie intrinsèque. Aussi les voies de résistance à l’apoptose ont été étudiées : les PS induisent une inhibition d’Akt, de Bcl-2, de NF-κB et de la voie autophagique et activent la voie p38/COX-2/PGE2 qui ne semble pas être impliquée dans un mécanisme de résistance à l’apoptose dans ce modèle d’étude. Enfin, l’efficacité de ces PS, et notamment de la PpIX-dSd, a été mise en évidence in vivo, à l’aide de xénogreffes sous-cutanées de cellules PC-3 effectuées sur des souris nudes. Ainsi, ces dérivés de PpIX-PA apparaissent comme de bons candidats dans le cadre du traitement du cancer de la prostate par PDT. / Prostate cancer is the most frequently diagnosed cancer among men aged 50 years and older in industrialized countries. Medical research developed methods of focal therapy to treat this type of cancer conservatively and not radically in order to improve the patients quality of life. With this in mind, photodynamic therapy (PDT) is based on the use of photosensitizers (PS) able to specifically target cancer cells and, once activated by light, induce cell death. Based on Green Chemistry, the Laboratoire de Chimie des Substances Naturelles (LCSN) from Limoges developed new PS: protoporphyrin IX, a PS widely studied, vectorized with polyamines (PA). The effects of spermidine-linked protoporphyrin IX (PpIX-dSd) and spermine-linked protoporphyrin IX (PpIX-dSm) were studied on human prostate cancer cells PC-3, DU145 and LNCaP. This study demonstrated that both PS have the expected ideal properties: a pure composition, no toxicity in dark and ability to specifically target tumor cells. Moreover, PpIX-PA induced apoptotic intrinsic pathway. In addition, pathways involved in apoptosis resistance were studied: PS inhibited Bcl-2, Akt, NF-¦ÊB and autophagy but activated p38/COX-2/PGE2 pathway which was not involved in apoptosis resistance in our model. Finally, in vivo experiments showed PpIX-PA efficiency using subcutaneous xenograft of PC-3 cells performed on nude mice. Thus, these derivatives of PpIX-PA appear to be good candidates in prostate cancer treatment by PDT.

Le développement de la thérapie photodynamique s’oriente vers la conception de photosensibilisateurs de 3ème génération, assemblages moléculaires adressés vers une cible biologique spécifique. Les nanoparticules développées dans un cadre de cette thèse sont constituées d’un cœur d’oxyde de gadolinium recouvert d’une couche de polysiloxane. Une chlorine est couplée de façon covalente dans cette couche de polysiloxane. Un surfactant hydrophile recouvre la surface des nanoparticules afin de les rendre biocompatibles. Enfin, les nanoparticules sont fonctionnalisées par le peptide ATWLPPR ciblant le récepteur d’intérêt neuropiline-1, surexprimé par les cellules endothéliales activées lors de l’angiogenèse tumorale. La stratégie est double : d'une part, il s'agit de traiter les lésions cancéreuses par thérapie photodynamique, d’autre part d'asphyxier le tissu tumoral en s'attaquant au réseau vasculaire qui l'alimente en nutriments et en oxygène. L'optimisation de la nanoplate-forme a porté sur la taille du cœur d’oxyde de gadolinium pour une intensité du signal IRM rehaussée, l’épaisseur de la coquille pour permettre la diffusion de l’oxygène indispensable à la réaction photodynamique donc à l’efficacité thérapeutique, le choix et la quantité d’unités peptidique couplées pour une sélectivité maximale pour les tissus tumoraux par rapport aux tissus sains / The development of photodynamic therapy (PDT) is focused on the conception of 3rd generation of photosensitizers which are molecular constructs targeted to specific biological receptors. The nanoparticles we have developed in this thesis are made of a gadolinium oxide core, a polysiloxane shell in which are covalently entrapped chlorins. Hydrophilic surfactants are grafted on the nanoparticles in order to make it biocompatible. Finally, the nanoparticles are functionalized by ATWLPPR peptide to target neuropilin-1 which is over-expressed on endothelial cells during tumoral angiogenesis. The aim of this strategy is both to treat cancer lesion by photodynamic therapy and to asphyxiate the tumoral tissue by destroying the vasculature that brings nutrients and oxygen to the tumor. The optimization of the nanoplate-form has been done by modifying the size of the gadolinium core for the best MRI signal, the size of the polysiloxane shell in order to let the oxygen diffuse in and out of the nanoparticle, the type and the amount of peptides coupled to the surfactant for the best selectivity for tumoral tissue compared to normal tissue

Cyanine dyes are attractive photosensitizers for photodynamic therapy due to their ease of structure modification and intense absorption in the near-infrared range. Photosensitizers that can bind to DNA and absorb at long enough wavelengths of light to deeply penetrate biological tissue are in high demand for treatment of cancer and other diseases. The following study analyzes the DNA interactions of three pentamethine cyanine dyes with very similar structures, all of which absorb light at wavelengths longer than 800 nm. The work described involves an extensive study of the photocleavage abilities and DNA binding characteristics of these dyes. Our lead compound was a bromophenyl meso substituted symmetrical quinoline cyanine dye. Spectroscopic data, gel electrophoresis experiments and other studies were used to provide evidence of DNA binding mode, ROS production, and of dye-sensitized DNA photocleavage at the unprecedented wavelength of 850 nm.

La thérapie photodynamique (PDT) est utilisée actuellement pour traiter certains cancers accessibles par irradiation laser. Son principe repose sur l'action combinée de la lumière et d'un principe actif nommé photosensibilisant (PS). La molécule photosensible génère des espèces réactives de l'oxygène sous l'action d'un rayonnement spécifique. Ces espèces sont fortement réactives et entrainent la mort des cellules alentour. Plusieurs facteurs limitent cependant l'efficacité de ce traitement. Dans cette optique, l'encapsulation d'un PS de seconde génération, le Foscan®, a conduit à la formation de nanoparticules qui ont été caractérisées et dont l'effet PDT a été étudié sur des cellules gliomales C6. Les nanoparticules présentent l'avantage de contrôler la solubilité du système, d'affiner le ciblage des traitements et de pouvoir adapter les doses de traitement. Le confinement du PS au sein de la nanoparticule peut permettre de réduire des effets secondaires et d'augmenter la concentration en principe actif au sein des tissus tumoraux. Par la suite, des nanoparticules chargées en complexes de ruthénium(II) ont été caractérisées. Ces complexes présentent des propriétés optiques adéquates pour de telles applications. De plus, une excitation biphotonique est réalisable, permettant d'augmenter la sélectivité et la profondeur du traitement. Des études préliminaires de l'effet PDT par excitation biphotonique ont été effectuées. / Photodynamic therapy (PDT) is currently used to treat certain cancers accessible by laser irradiation. Its principle is based on the combined action of light and a drug called photosensitizer (PS). The photosensitive molecule generates reactive oxygen species through the action of a specific radiation. These species are highly reactive, entailing the death of surrounding cells. However, several factors limit the effectiveness of this treatment. In this context, the encapsulation of a second-generation PS, Foscan®, led to the formation of nanoparticles that have been characterized and whose PDT effect was studied on C6 glioma cells. The nanoparticles have the advantage of controlling the solubility of the system, better targeting of treatment and to adjust the dose of treatment. Containment of the PS inside nanoparticles can reduce side effects and increase the concentration of active drug in tumor tissues. Thereafter, the nanoparticles loaded with ruthenium(II) complexes have been characterized. These complexes show optical properties suitable for such applications. In addition, a two-photon excitation is possible, improving the selectivity and increasing the depth of treatment. Preliminary studies of the effect of PDT photon excitation were performed.

A prevenção das doenças periimplantares baseia-se em procedimentos de rotina na clínica, com a remoção mecânica do biofilme associada ou não de agentes antimicrobianos locais e sistêmicos. No entanto, o controle do biofilme oral sobre a superfície de implantes é dificultado particularmente sobre as superfícies rugosas do titânio, que apesar de facilitarem a osseointegração, também favorecem a formação do biofilme. Objetivos: Objetivou-se analisar in vitro o efeito da TFD (Terapia fotodinâmica) usando curcumina como fotossensibilizador sobre o biofilme formado na superfície de discos de titânio com superfície rugosa e lisa. Material e Métodos: Biofilme mono espécie de Streptococus gordonii, colonizador inicial do biofilme dental, foi formado em superfícies lisas (usinadas) e rugosas (tratadas) de discos de titânio por 72 horas. Os discos lisos e rugosos foram então distribuídos em 3 grupos: tratados por 5 minutos com curcumina (60?M), clorexidina 0,12% como controle positivo e solução de DMSO (dimetilsufóxido), etanol e água como controle negativo (veículo da curcumina). As amostras foram divididas em 2 sub-grupos: ativado por LED azul (455-492nm) por 7 minutos e não-ativado. A atividade metabólica do biofilme foi determinada pelo método de redução do Sal tetralisol XTT e os resultados analisados estatisticamente pela análise da variância (ANOVA) seguida pelo teste de Tukey (p < 0,05). Resultados: Na ausência de luz, apenas o tratamento com clorexidina promoveu redução microbiana (controle positivo). O tratamento com curcumina ativada pela luz azul reduziu o número de bactérias viáveis no biofilme em 71% nos discos lisos e em 77% nos rugosos, não havendo diferença estatística com o controlepositivo.Conclusão: Os dados in vitro indicam que TFD associada à curcumina tem atividade sobre biofilme microbiano, sugerindo seu potencial no controle do biofilme oral sobre a superfície de titânio, e que este efeito independe da topografia da superfície. / Prevention of periimplant diseases is based on routine procedures in the clinic, with the mechanical removal of biofilm associated or not with local and systemic antimicrobial agents. However, the control of oral biofilm on the surface of implants is particularly difficult on the rough surfaces of titanium, which, although facilitating osseointegration, also favors biofilm formation. Objectives: The objective of this study was to analyze in vitro the effect of PDT using curcumin as a photosensitizer on the biofilm formed on the surface of titanium discs with a rough and smooth surface. Material and Methods: Biofilm mono species of Streptococus gordonii, initial colonizer of the dental biofilm, was formed on smooth (machined) and rough (treated) surfaces of titanium discs for 72 hours. The smooth and rough discs were then divided into 3 groups: treated for 5 minutes with curcumin (60 ?M), 0.1% chlorhexidine as a positive control and DMSO, ethanol and water solution as a negative control. The samples were divided into 2 subgroups: activated by blue LED (455-492nm) for 7 minutes and non-activated. The metabolic activity of the biofilm was determined by the reduction XTT salt method and the results analyzed statistically by ANOVA followed by the Tukey\'s test (p <0.05) Results: In the absence of light, only the chlorhexidine treatment promoted microbial reduction (positive control). The blue light-activated curcumin treatment reduced the number of viable bacteria in the biofilm in 71% in the smooth discs and in 77% in the wrinkles, and there was no statistical difference with the positive control. Conclusion: In vitro data indicate that PDT associated with curcumin has activity on microbial biofilm, suggesting its potential in the control of oral biofilm on the titanium surface, and that this effect is independent of surface topography.