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Interstitial brachytherapy (BT) is generally used for the treatment of well-confined solid tumors. One example of this is in the treatment of prostate tumors by permanent placement of radioactive seeds within the prostate gland, where low doses of radiation are delivered for several months. However, successful implementation of this technique is hampered due to several posttreatment adverse effects or symptoms and operational and logistical complications associated with it. Recently, with the advancements in nanotechnology, radioactive nanoparticles (radio-NPs) functionalized with tumor-specific biomolecules, injected intratumorally, have been reported as an alternative to seed-based BT. Successful treatment of solid tumors using radio-NPs has been reported in several preclinical studies, on both mice and canine models. In this article, we review the recent advancements in the synthesis and use of radio-NPs as a substitute to seed-based BT. Here, we discuss the limitations of current seed-based BT and advantages of radio-NPs for BT applications. Recent progress on the types of radio-NPs, their features, synthesis methods, and delivery techniques are discussed. The last part of the review focuses on the currently used dosimetry protocols and studies on the dosimetry of nanobrachytherapy applications using radio-NPs. The current challenges and future research directions on the role of radio-NPs in BT treatments are also discussed.

The synthesis and engineering of nanomaterials offer more robust systems for the treatment of cancer, with technologies that combine therapy with imaging diagnostic tools in the so-called nanotheranostics. Among the most studied systems, there are quantum dots, liposomes, polymeric nanoparticles, inorganic nanoparticles, magnetic nanoparticles, dendrimers, and gold nanoparticles. Most of the advantages of nanomaterials over the classic anticancer therapies come from their optimal size, which prevents the elimination by the kidneys and enhances their permeation in the tumor due to the abnormal blood vessels present in cancer tissues. Furthermore, the drug delivery and the contrast efficiency for imaging are enhanced, especially due to the increased surface area and the selective accumulation in the desired tissues. This property leads to the reduced drug dose necessary to exert the desired effect and for a longer action within the tumor. Finally, they are made so that there is no degradation into toxic byproducts and have a lower immune response triggering. In this article, we intend to review and discuss the state-of-the-art regarding the use of nanomaterials as therapeutic and diagnostic tools for lung, breast, and prostate cancer, as they are among the most prevalent worldwide.

At a nano-level, optical properties of gold are unique and gave birth to an emerging platform of nanogold-based systems for diverse applications, because gold nanoparticle properties are tunable as a function of size and shape. Within the available techniques for the synthesis of gold nanoparticles, the radiolytic synthesis allows proper control of the nucleation process without the need for reducing agents, in a single step, combined or not with simultaneous sterilization. This review details and summarizes the use of radiation technologies for the synthesis and preparation of gold nanoparticles concerning fundamental aspects, mechanism, current pathways for synthesis and radiation sources, as well as briefly outlines final applications and some toxicity aspects related to nanogold-based systems.

Purpose. Nanoparticles (NPs) with radioactive atoms incorporated within the structure of the NP or bound to its surface, functionalized with biomolecules are reported as an alternative to low-dose-rate seed-based brachytherapy. In this study, authors report a mathematical dosimetric study on low-dose rate brachytherapy using radioactive NPs. Method. Single-cell dosimetry was performed by calculating cellular S-values for spherical cell model using Au-198, Pd-103 and Sm-153 NPs. The cell survival and tumor volume versus time curves were calculated and compared to the experimental studies on radiotherapeutic efficiency of radioactive NPs published in the literature. Finally, the radiotherapeutic efficiency of Au-198, Pd-103 and Sm-153 NPs was tested for variable: administered radioactivity, tumor volume and tumor cell type. Result. At the cellular level Sm-153 presented the highest S-value, followed by Pd-103 and Au-198. The calculated cell survival and tumor volume curves match very well with the published experimental results. It was found that Au-198 and Sm-153 can effectively treat highly aggressive, large tumor volumes with low radioactivity. Conclusion. The accurate knowledge of uptake rate, washout rate of NPs, radio-sensitivity and tumor repopulation rate is important for the calculation of cell survival curves. Self-absorption of emitted radiation and dose enhancement due to AuNPs must be considered in the calculations. Selection of radionuclide for radioactive NP must consider size of tumor, repopulation rate and radiosensitivity of tumor cells. Au-198 NPs functionalized with Mangiferin are a suitable choice for treating large, radioresistant and rapidly growing tumors.

Photobiomodulation also known as low-level laser (or light) therapy (LLLT), has been known for almost 50 years but still has not gained widespread acceptance, largely due to uncertainty about the molecular, cellular, and tissular mechanisms of action. However, in recent years, much knowledge has been gained in this area, which will be summarized in this review. One of the most important chromophores is cytochrome c oxidase (unit IV in the mitochondrial respiratory chain), which contains both heme and copper centers and absorbs light into the near-infrared region. The leading hypothesis is that the photons dissociate inhibitory nitric oxide from the enzyme, leading to an increase in electron transport, mitochondrial membrane potential, and adenosine triphosphate production. Another hypothesis concerns light-sensitive ion channels that can be activated allowing calcium (Ca2+) to enter the cell. After the initial photon absorption events, numerous signaling pathways are activated via reactive oxygen species, cyclic AMP, NO, and Ca2+, leading to activation of transcription factors. These transcription factors can lead to increased expression of genes related to protein synthesis, cell migration and proliferation, anti-inflammatory signaling, anti-apoptotic proteins, and antioxidant enzymes. Stem cells and progenitor cells appear to be particularly susceptible to LLLT.

Radiolytic synthesis and phytochemical-driven gold reduction for the generation of nanoparticles are successful examples of Green Chemistry applied for nanomaterials. The present work compares these two green approaches focusing on hydrodynamic size, stability over time, optical properties and toxicity in NIH 3T3 (ATCC® CRL-1658™) cells and Danio rerio (Zebra Fish). The radiolytic synthesis was performed by mixing 1 mM NaAuCl4; polyvinyl pyrrolidone 0.5%, AgNO3 6 × 10−5 M, propan-2-ol 0.2 M and acetone 0.06 M, followed by irradiation at 15 kGy (5 kGy h−1, 60Co source). The EGCG-functionalized nanoparticles were synthesized by mixing 1.6 mM of Au with 0.8 mM of EGCG in phosphate buffer (10 mM) for 2 h. Both methods yield the formation of gold nanoparticles featuring plasmon resonance bands at 520–530 nm, polydispersity above 0.3 was relevant only for the radiolytic protocol. Regarding stability over time, after 30 days, the nanoparticles synthesized radiolytically presented no relevant size changes, while some aggregation was observed for the EGCG-particles. The same nanoparticles demonstrated a lack of stability in high ionic strength medium. Slight toxicity was observed for the EGCG-nanoparticles in Danio rerio, with an IC50 calculated as 40.49%, while no IC50 was established within the concentration range of radiolysis-AuNPs used in this study. In conclusion, both green methods generated nanoparticles with good control of size and optical properties, especially via reduction by EGCG. However, the stability and toxicity results were found to be more promising for the radiolytically synthesized gold nanoparticles.

Papain-based nanoparticles were recently developed using radiation technologies and proven effective to generate nanosized crosslinked papain particles with preserved enzymatic activity. The applications of such nanostructured systems are expected to be similar to native papain with considerable biopharmaceutical advantages and concern drug loading among other biotechnological applications. The nature of such crosslinks and the possibility to provide simultaneous sterilization have been hypothesized but remain not totally clarified. This manuscript advances the discussion on the radiation-induced synthesis of protein nanoparticles by approaching the nature of the crosslinking and the possible contribution of bityrosine linkages and disulfide bridges to the overall nanoparticle assembly as well as the feasibility of the simultaneous sterilization process under the pre-established conditions of processing. Papain nanoparticles were synthesized and characterized according to size, proteolytic activity, bityrosine, cysteine content and molecular weight by SDS-PAGE upon sonication at 40 kHz. Bacterial identification and the sterility tests were performed in accordance with ISO 11737 prior to and after inoculating 106 CFU of Corynebacterium xerosis. Our experiments evidenced the crosslinking of rather intra- than intermolecular nature and a contribution of cysteine bridges and bityrosine linkages to the stabilization and formation of the papain nanoparticle assembly. The technique was effective to promote simultaneous crosslinking and sterilization at the established conditions of processing and may be validated in accordance with the ISO 11137.

6.1 Dose Dependence and Dose Rate Effects: The Biphasic Curve A biphasic response has been demonstrated many times in LLLT research, and the Arndt-Schulz law is frequently quoted as a suitable model to describe the dose-dependent effects of LLLT. The concept of the law dates from the end of the nineteenth century, when H. Schulz published a series of papers that examined the activity of various kinds of poisons (iodine, bromine, mercuric chloride, arsenious acid, etc.) on yeast, showing that almost all of these agents have a slightly stimulatory effect on the yeast metabolism in low doses. He and psychiatrist R. Arndt developed a principle that later became known as the Arndt-Schulz law, stating that weak stimuli slightly accelerate vital activity, stronger stimuli raise it further until a peak is reached, and even stronger stimuli suppress it until a negative response is finally achieved. In 1960, Townsend and Luckey surveyed the field of classic medical pharmacology and published a list of 100 substances capable of causing inhibition at high concentrations and stimulation at low concentrations, and they termed the phenomenon “hormoligosis.” The modern term “hormesis” was first used by Stebbing in 1982 and has been thoroughly reviewed by Calabrese. In the context of LLLT, the increasing “stimulus” may be irradiation time or increased irradiance. This nonlinear effect contradicts the Bunsen-Roscoe rule of reciprocity (originally formulated for the visual detection of light by photoreceptors), which predicts that if the products of the exposure time in seconds and irradiance in mW/cm 2 are equal, i.e., the energy density is the same, then the changes in the biological endpoint will be equal. This inverse linear relationship between irradiance and time has frequently failed in LLLT research.

20.1 Disappointment at Current Lack of Progress Despite the impressive accomplishments that have steadily accumulated since the 1960s that now consist of the publication of thousands of peer-reviewed papers [that can be retrieved by a PubMed search using the MeSH term “LLLT” and a new MeSH term “photobiomodulation therapy” (PBM)] and hundreds of clinical trials, many of which have been high-quality, randomized, and well-controlled, LLLT has still not reached the stage of acceptance by mainstream medicine. There remains considerable skepticism (and sometimes frank disbelief) amongst biomedical scientists, the medical profession, and the public at large. The reasons for this skepticism and disbelief are many and various, and they differ depending on the source. Biomedical scientists often refer to a lack of mechanism and the absence of agreement on dosimetry and parameters. Physicians often claim there is a lack of large clinical trials and not enough systematic reviews. Hospital and insurance administrators cannot agree on coverage and reimbursement. Finally (and regrettably), there has been marketing hype, over-promising, and frank misinformation from some of the companies that make devices (lasers, LED arrays, mixed clusters) that are used in the LLLT industry.

b]15.1 Effects of LLLT on Skin 15.1.1 Skin rejuvenation Skin aging is a process that can present itself relatively early on in life, sometimes even as soon as 20 - 30 years of age. Common signs and symptoms associated with skin aging include skin wrinkling, skin dyspigmentation, telangiectasia, and reduced tissue elasticity. At the histological and molecular level, common noticeable features include a reduction in collagen content, fragmentation of collagen fibers, elastotic degeneration of elastic fibers, the appearance of dilated and tortuous dermal vessels, disorientation and atrophy of the epidermis, and up-regulation of matrix metalloproteinases (MMPs), especially MMP-1 and MMP-2. Skin aging can be influenced by both time (normal aging) and environmental factors, but the single most influential factor responsible for accelerated skin aging is believed to be ultraviolet (UV) radiation-induced photodamage.

The lymphatic system plays a critical role in the process of reducing inflammation and edema, as well as a major role in the immune response. It moves fluid (lymph) from interstitial spaces in tissues via a network of collecting vessels to the lymph nodes, where it is mostly emptied into the venous system. Some fluid moves further along the lymphatic chain to other lymph nodes and eventually empties into the thoracic duct. PBM reduces swelling, and it seems likely that the lymphatic system is involved, although limited evidence exists to confirm this. A PubMed search for a range of PBM terms (see Chapter 1) AND edema OR oedema OR swelling returns over 50 abstracts. Most of these abstracts are for post-mastectomy lymphedema, post-surgical swelling, acute soft-tissue injury, and arthritic joints. The mechanism by which light affects edema has not been adequately explored, although it makes sense that it should because nitric oxide (NO) modulates lymphatic vessel contraction and subsequent lymph flow, and it has been established that PBM releases stores of NO8–10 and subsequently improves blood flow. As with blood vessels, NO is produced by endothelial nitric oxide synthase (eNOS) in lymphatic endothelial cells, which in turn affects the dilation and force of lymph vessel contractions. Small amounts of NO are produced (by eNOS) when lymph vessels are stretched (by movement or a stretch/massage technique), and this leads to alternating periods of diastolic filling and systolic ejection of lymphangions (the tiny functional units of the collecting lymphatic system). Excessive amounts of NO produced by inducible nitric oxide synthase (iNOS) during inflammation can overwhelm the NO gradients produced by eNOS. The suppression of eNOS by iNOS disrupts the contraction/relaxation cycle in favor of excessive contraction and subsequent reduced flow.

Estudos com tratamento hipertérmico de tumores utilizando nanopartículas metálicas têm sido realizados durante as últimas décadas e mostram resultados bons quanto à remissão de tumores, por vezes chegando à cura completa. O mesmo acontece em relação aos tratamentos baseados em ação fotodinâmica de fotossensibilizadores. Tratamentos aliando a terapia hipertérmica com nanopartículas de ouro e a terapia fotodinâmica com diversos fotossensibilizadores tem efeito sinérgico e apresenta excelente potencial terapêutico, em que pese serem necessários mais estudos para que uma nova terapia conjunta possa ser implementada. A proposta deste trabalho foi investigar esse efeito sinérgico utilizando nanobastões de ouro complexados com fotossensibilizadores. Após a síntese dos nanobastões pelo método de seeding, a eficácia do tratamento fotodinâmico e da terapia hipertérmica, separadamente, foi investigada. A metodologia do recobrimento dos nanobastões por fotossensibilizador, em um primeiro momento, não logrou êxito com a porfirina, porém com a ftalocianina tetracarboxilada se mostrou mais eficaz. A taxa de fotodegradação da ftalocianina em solução foi investigada como parâmetro para a eficiência em geração de oxigênio singlete. Após centrifugação e lavagem das nanopartículas, no entanto, evidenciou-se por espectrofotometria que o fotossensibilizador não permaneceu aderido aos nanobastões. Em um segundo momento, optamos por recobrir os nanobastões por porfirinas tetrassulfonadas, com ou sem grupamentos metil-glucamina. Após o processo de recobrimento, essas ftalocianinas formaram complexos iônicos com o CTAB que recobre os nanobastões. Os complexos nanobastões-ftalocianinas foram analisados por microscopia eletrônica de transmissão e as taxas de geração de oxigênio singlete e de radical hidroxil foram investigadas. Além disso, foram utilizadas para testes in vivo e in vitro com células de melanoma melanótico (B16F10) ou amelanótico (B16G4F). As células tumorais em cultura ou os tumores em camundongos C57BL6 foram irradiados com luz em 635 nm e os tumores foram observados por 15 dias após o tratamento. Houve evidente aumento na geração de oxigênio singlete por ambos fotossensibilizadores, e maior geração de radicais livres por parte do fotossensibilizador metilglucaminado. O oposto ocorre com o fotossensibilizador sem metilglucamina. Houve, também, moderada citotoxicidade no escuro quando células foram incubadas com nanopartículas recobertas por ftalocianinas ou não. Quando ativados pela luz, os complexos ftalocianinas-nanobastões desencadearam um aumento de 5ºC no meio de cultura das células, e a morte celular observada foi extensa (91% para a linhagem B16G4F e 95% para a linhagem B16F10). Tanto os resultados in vitro quanto os in vivo indicam que as propriedades das ftalocianinas testadas são melhoradas significativamente quando elas estão complexadas aos nanobastões. Este é um estudo pioneiro por utilizar duas porfirinas tetrassulfonadas específicas e por utilizar o mesmo comprimento de onda para a ativação dos fotossensibilizadores e nanobastões. Studies with hyperthermic tumor ablation using metallic nanoparticles have been performed on the last decades, and show promising results on tumor remission, sometimes achieving the complete cancer elimination. The same occurs regarding on treatments based on photodynamic activity of photosensitizer compounds. Studies indicate that those therapeutic interventions - hyperthermic therapy using gold nanorods and photodynamic activity with many photosensitizers - together can present a synergistic effect, and offer a great therapeutic potential, although more investigation needs to be performed before such approach could be implemented. We proposed to investigate the effect of the attachment of photosensitizers onto the surface of gold nanorods (well-characterized devices for hyperthermia generation). After nanorods synthesis through a seed-mediated method, the PDT and hyperthermia\'s efficacy was assessed separately. The method used for covering the gold nanorods with photosensitizers did not permit, in a first approach, the attachment of porphyrins onto the nanoparticles surface, but the attachment of tetrasulfonated phthalocyanines was more successful. The phthalocyanine\'s degradation rate was assessed as an indirect parameter of singlet oxygen generation. After centrifuging and washing the nanoparticles, we saw that the photosensitizers do not keep attached to the nanorods. On a second approach, we chose to recover the nanorods with two zinc phthalocyanines - with or without methyl-glucamine groups. After the recovering process, the phthalocyanines formed ionic complexes with the CTAB that is previously recovering the nanoparticles. The nanorod-phthalocyanines complexes were analyzed by TEM, and their singlet oxygen and hydroxyl radical generation yield were assessed. Furthermore, they were tested in vitro in melanoticB16F10 and amelanotic B16G4F melanoma cells, and in vivo. The tumor cells (in vitro) and the tumor tissue (in vivo) with nanoparticles were irradiated with laser (at 635 nm), and the tumor growth in mice was observed for 15 days after the laser irradiation. It is evident the increase in the singlet oxygen generation, and higher HPF activation for the glucaminated Pc, but the inverse for the other photosensitizer. It seems like there is a type I to type II switch on the action mechanism of the latter Pc. A mild cytoxocity was observed with the nanorods conjugated with photosensitizer in the dark, but when they are activated by light (and taken into account a 5ºC rise in the temperature because of the surface plasmon resonance from the gold nanorods), the cell killing is intense (91% for B16G4F cell line, and 95% for B16F10 cell line). Both in vitro and in vivo results indicate that the photodynamic properties of the phthalocyanines tested are enhanced when they are attached onto the nanorods surface. This is a novel study because we used two tetrasulfonated phthalocyanines and because we used the same wavelength to activate both the nanorods and the photosensitizers.

This study intended to evaluate the effects of a papain-gel with a red-light absorbing pigment (methylene blue – MB) to mediate photodynamic therapy (PDT) against Streptococcus mutans biofilms. The PapaMBlue was compared with free MB to generate reactive oxygen species using fluorescence probes (SOSG and HPF). PDT (660-nm light) was carried out against S. mutans biofilms grown on either plastic dishes or on collagen membrane and assayed by CFU, live-dead staining using confocal microscopy, transmission electron microscopy and H&E staining for collagen films. Cytotoxicity and subcellular localization was studied in human fibroblasts. Sponges of bioabsorbable type I collagen membrane were exposed to papain based gel, irradiated with laser and analyzed about their integrity by ATR-FTIR. The PapaMBlue produced higher amounts of singlet oxygen and hydroxyl radicals than free MB, possibly due to better disaggregation of the dye in solution. The PapaMBlue antimicrobial effects on biofilms proved to be capable of reducing the S. mutans. Both MTT and PrestoBlue assays showed higher cell viability and metabolism scores in fibroblasts treated with PapaMBlue and MB, possibly due to stimulation of mitochondrial activity and that collagen triple helix is unaffected. The PapaMBlue is equally effective as MB in destroying S. mutans biofilms growing on plastic or collagen without affecting fibroblasts., National Institutes of Health (U.S.) (Grant R01AI050875)

Photodynamic therapy (PDT) uses the combination of non-toxic photosensitizers and harmless light to generate reactive oxygen species that destroy tumors by a combination of direct tumor cell killing, vascular shutdown, and activation of the immune system. It has been shown in some animal models that mice that have been cured of cancer by PDT, may exhibit resistance to rechallenge. The cured mice can also possess tumor specific T-cells that recognize defined tumor antigens, destroy tumor cells in vitro, and can be adoptively transferred to protect naive mice from cancer. However, these beneficial outcomes are the exception rather than the rule. The reasons for this lack of consistency lie in the ability of many tumors to suppress the host immune system and to actively evade immune attack. The presence of an appropriate tumor rejection antigen in the particular tumor cell line is a requisite for T-cell mediated immunity. Regulatory T-cells (CD25+, Foxp3+) are potent inhibitors of anti-tumor immunity, and their removal by low dose cyclophosphamide can potentiate the PDT-induced immune response. Treatments that stimulate dendritic cells (DC) such as CpG oligonucleotide can overcome tumor-induced DC dysfunction and improve PDT outcome. Epigenetic reversal agents can increase tumor expression of MHC class I and also simultaneously increase expression of tumor antigens. A few clinical reports have shown that anti-tumor immunity can be generated by PDT in patients, and it is hoped that these combination approaches may increase tumor cures in patients.

Ultimamente têm-se buscado tratamentos menos invasivos para o câncer, como os que utilizam campos magnéticos ou luz, e dentre esses últimos, aqueles que fazem uso de materiais, geralmente metálicos, com propriedade de ressonância plasmônica de superfície. O tratamento hipertérmico encaixa-se neste perfil e já apresenta resultados promissores com nanoshells de sílica recoberta por ouro e com nanobarras de ouro maciço, apesar de pouco se saber sobre o mecanismo de ação e sobre como as vias de morte celular são ativadas em tal tratamento. A síntese das nanobarras envolve o uso do composto brometo de cetiltrimetilamônio (CTAB), o qual permanece aderido à superfície das mesmas, porém é caracterizado por apresentar extrema citotoxicidade, fato que incita a modificação do recobrimento das nanopartículas por um biopolímero mais compatível. Estudos recentes indicam que o CTAB aderido à membrana não apresenta citotoxicidade considerável, porém há poucos dados que confirmem tal hipótese na literatura. Este trabalho se propôs a investigar a via de ativação da morte celular, bem como confirmar a hipótese de que as partículas recobertas por CTAB podem ser utilizadas para tratamento antitumoral fototérmico in vivo de forma segura. Para isso, nanobarras de ouro foram sintetizadas pelo método de seeding, sendo parte delas centrifugadas e lavadas com água deionizada por três vezes para retirar o CTAB e a outra parte deixada com CTAB no meio. As partículas foram testadas in vitro pelo teste de citotoxicidade pelo [brometo de 3-(4, 5-dimetiltiazol-2-yl)-2,5-difeniltetrazólio] (MTT) nas linhagens celulares HTC, HepG2, HT-29 e 786-O, e também foram testadas quanto à sua viabilidade com o tempo decorrido desde sua síntese. Após confirmar que as nanobarras centrifugadas e lavadas podem ser utilizadas no tratamento hipertérmico sem riscos à saúde e após verificar que as seeds e as nanobarras devem ser utilizadas até 48 horas depois de sua síntese, as nanopartículas foram utilizadas para tratamento de tumor de Ehrlich (induzido no dorso de camundongos). Para isso, foram organizados quatro grupos experimentais: L (camundongos não receberam nanopartículas, irradiados com laser em 808 nm), N (camundongos receberam nanopartículas, não irradiados com laser), H (camundongos receberam nanopartículas e irradiados com laser em 808 nm) e Controles (camundongos não receberam nanopartículas nem irradiação por laser). O material tumoral foi coletado após a irradiação e submetido à análise histológica, ao teste de quimiluminescência para avaliar a lipoperoxidação de membrana e ao teste de TRAP (do inglês, Total Radical-Trapping Antioxidant Parameter) para avaliar a capacidade antioxidante total. Após a irradiação com 2 W/\'CM POT.2\' ou 720 mW/\'CM POT.2\' de intensidade, houve evidente redução do volume tumoral nos animais do grupo H tratados com laser na maior potência utilizada, com um aumento de 47ºC (temperatura final de 79ºC) observado localmente. Nos animais do grupo H tratados com laser na menor potência utilizada, os danos foram menores. Os animais dos grupos L e H apresentaram semelhante lipoperoxidação, maior que no grupo N (estatisticamente significante somente nos animais tratados com laser em intensidade de 2 W/\'CM POT.2\'), e a capacidade antioxidante dos tumores dos animais do grupo H foi elevada no protocolo com laser em 2 W/\'CM POT.2\'. Os resultados indicam que a necrose é a via de morte ativada prioritariamente neste caso e que o tratamento com as nanobarras se mostrou eficaz. Less invasive cancer treatments, likewise those based on magnetic fields or light, are in the most common aims of researchers nowadays. Regarding light based treatments, those in which metallic, plasmonic materials are highlighted in research field. Hiperthermic treatment fits this profile, once it already presents promising results with gold-coated silica nanoshells and with gold nanorods, although little is known about its action mechanism or about how cell death pathways are activated. The compound cetyltrimethylammonium bromide (CTAB) is necessary for the nanorods synthesis, but is known to be extremely cytotoxic, fact that instigates the modification of nanorods surface coating by a compatible biopolymer. Recent studies indicate that surface-adhered CTAB does not present significant cytotoxicity, but there are few evidences to confirm this hypothesis in the literature. This study aims to investigate the cell death pathway that can be activated, as well as to confirm the possibility of safe CTAB-coated nanoparticles use in antitumor in vivo treatments. For that, gold nanorods were synthesized by the seeding method and part of them were centrifuged and washed with deionized water to eliminate CTAB of the solution and the rest remained with CTAB. The particles were tested in vitro by [3-(4, 5-dimethythiazol-2-yl)-2,5-diphenyltetrazolium bromide] (MTT) cytotoxicity test, in HTC, HepG2, HT-29 and 786-O cancer cell lines, and investigated regarding their viability through time after their synthesis. After confirming that centrifuged and washed nanorods can be used in hiperthermic therapy without health risks, and after find out that seeds and nanorods must be used within 48 hours after their synthesis, those nanoparticles were used for in vivo hyperthermic Ehrlich tumor (induced on the back of mices) treatment. Four experimental groups were organized: L (mice did not receive nanoparticles, treated with laser at 808 nm), N (mice received nanoparticles, not treated with laser), and H (mice received nanoparticles and treated with laser at 808 nm) and Controls (mice did not receive nanoparticles and were not treated with laser). A tumor biopsy was taken after laser irradiation and was subjected to histological analysis, by a chemiluminescence assay to evaluate membrane lipoperoxidation, and by Total Radical-Trapping Antioxidant Parameter (TRAP) assay as well, to evaluate total antioxidant capacity. After irradiation with laser (intensities of 2 W/\'CM POT.2\' or 720 mW/\'CM POT.2\'), there was an evident tumor volume reduction in animals of H group treated with higher power laser, with a 47ºC rise in temperature (final temperature was 79ºC) observed locally. The damages in the tumors irradiated with lower power laser were less intense. The animals of L and H groups showed similar membrane lipoperoxidation, which was more intense than in N animals (statistically significant just in the animals treated with higher intensity of radiation). The antioxidant capacity of H animals tumor was elevated also in the animals treated with higher energy. Our results indicate that necrosis is the main activated cell death pathway in this case, and that nanorods treatment is worth it.

Breast cancer is the malignant neoplasia with the highest incidence in women worldwide. Chronic oxidative stress and inflammation have been indicated as major mediators during carcinogenesis and cancer progression. Human studies have not considered the complexity of tumor biology during the stages of cancer advance, limiting their clinical application. The purpose of this study was to characterize systemic oxidative stress and immune response parameters in early (ED; TNM I and II) and advanced disease (AD; TNM III and IV) of patients diagnosed with infiltrative ductal carcinoma breast cancer. Oxidative stress parameters were evaluated by plasmatic lipoperoxidation, carbonyl content, thiobarbituric reactive substances (TBARS), nitric oxide levels (NO), total radical antioxidant parameter (TRAP), superoxide dismutase, and catalase activities and GSH levels. Immune evaluation was determined by TNF-α, IL-1β, IL-12, and IL-10 levels and leukocytes oxidative burst evaluation by chemiluminescence. Tissue damage analysis included heart (total CK and CKMB), liver (AST, ALT, GGT), and renal (creatinine, urea, and uric acid) plasmatic markers. C-reactive protein (CRP) and iron metabolism were also evaluated. Analysis of the results verified different oxidative stress statuses occur at distinct cancer stages. ED was characterized by reduction in catalase, 8-isoprostanes, and GSH levels, with enhanced lipid peroxidation and TBARS levels. AD exhibited more pronounced oxidative status, with reduction in catalase activity and TRAP, intense lipid peroxidation and high levels of NO, TBARs, and carbonyl content. ED patients presented a Th2 immune pattern, while AD exhibited Th1 status. CRP levels and ferritin were increased in both stages of disease. Leukocytes burst impairment was observed in both the groups. Plasma iron levels were significantly elevated in AD. The data obtained indicated that oxidative stress enhancement and immune response impairment may be necessary to ensure cancer progression to advanced stages and may result from both host and tumor inflammatory mediators.

Several adverse effects of chemotherapy treatments have been described, and most of these effects are associated with direct interactions between blood cells and indirect effects generated during the oxidative metabolism of antineoplastic drugs. In this study we evaluated the oxidative systemic status and hematological profiles of breast cancer patients with advanced ductal infiltrative carcinoma treated with doxorubicin (DOX) or paclitaxel (PTX) within 1 h after chemotherapy. Blood analyses included evaluation of hemogram, pro-oxidative markers, and antioxidant status. The results showed that advanced breast cancer diseased (AD) patients without previous chemotherapy presented anemia and high oxidative stress status characterized by elevated levels of lipid peroxidation and nitric oxide, and reduced catalase activity when compared with controls. DOX-treated patients exhibited increased anemia and reduced antioxidant status, which was revealed by decreases in reduced glutathione levels and the total antioxidant capacity of plasma; however, these changes did not lead to further increases in lipid peroxidation or carbonyl proteins when compared with the AD group. PTX-treated patients also showed increased anemia, lactate dehydrogenase leakage, and enhanced lipid peroxidation. These data reveal for the first time that patients subjected to chemotherapy with DOX or PTX present immediate systemic oxidative stress and red blood cell oxidative injury with anemia development. These findings provide a new perspective on the systemic redox state of AD and patients subjected to chemotherapy regarding oxidative stress enhancement and its possible involvement in the aggravation of chronic anemia.

5 and 7Gy with AO concentrations of 0, 1 and 2 g/mL. For MDAMB-231, 48h after radiation therapy, cells treated with 1 g/mL showed 50% more AO cell death than those without AO, and about 85% for cells treated with 2 g/mL of AO; meanwhile, the results for MCF-7 were 22% more dead cells with 1 g/mL, and 36% with 2 g/mL when compared to those without AO. These results show RDThas the potential to increase the volume of treated tissuewhile decreasing the side effects of radiotherapy, and AO showed to be an efficient radiosensitizer.

As nanopartículas de ouro (AuNPs) vem sendo amplamente estudadas por atenderem às necessidades de sistemas nanocarreadores na terapia e diagnóstico de câncer. Elas podem ser usadas no direcionamento e liberação de fármacos a sítios ou grupos celulares específicos, atuar como radiossensibilizadores e em terapias fototérmicas como agente gerador de calor. Um número significativo de estudos demonstrou suas possíveis aplicações, tais como biossensores, contraste na imagiologia biológica, em sistemas de liberação de fármacos, terapia e diagnóstico do câncer. Assim, as nanopartículas de ouro são consideradas promissoras no desenvolvimento de novos compostos com potencial aplicação na medicina oncológica, no tratamento de inflamações crônicas, infecções, doenças degenerativas e autoimunes. No entanto, apesar das formas nanométricas de ouro apresentarem menor toxicidade comparada aos muitos outros nanomateriais, a toxicidade dessas partículas deve ser minuciosamente avaliada. O maior desafio é propor um método para funcionalizar a superfície das nanopartículas, e assim modular sua farmacocinética e farmacodinâmica, além de atender aos requisitos de toxicidade para aprovação e aplicação de um nanobiomaterial. O objetivo desse estudo foi desenvolver um método de síntese de nanopartículas de ouro (AuNPs) com potencial aplicação como um nanobiomaterial na teranóstica (terapia e diagnóstico) do câncer. Para tanto, foi utilizado o conceito de nanotecnologia verde, em que compostos fitoquímicos com potencial redutor foram utilizados no preparo das AuNPs. Também foi estabelecido um método de funcionalização de AuNPs por recobrimento com albumina do soro bovino e humano utilizando radiação ionizante. A importância do recobrimento com albumina está relacionada a afinidade dessa proteína com os receptores glicoproteicos GP60, que são encontrados em diversas células tumorais, além de contribuir potencialmente com a cinética das nanopartículas de ouro. A caracterização físico-química das AuNPs e a reprodutibilidade do método foi avaliada com base nos ensaios de caracterização realizados pelas técnicas de espectrofotometria UV-Vis/Fluorescência, espalhamento dinâmico de luz (DLS), potencial Zeta, microscopia eletrônica de transmissão (MET), espectroscopia de emissão óptica por plasma acoplado indutivamente (ICP-OES) e eletroforese em gel (SDS-PAGE). A estabilidade foi avaliada em relação à temperatura, pH, concentração de NaCl, PBS, solução contendo aminoácidos e meio de cultura celular DMEM sem e com suplementação de soro fetal bovino. As linhagens celulares utilizadas foram câncer de próstata humano (PC3), adenocarcinoma de mama humano (MDA-MB 231) e células de tecido pulmonar de hamster chinês macho (V79-4). Nas concentrações testadas as AuNPs não apesentaram citotoxicidade in vitro utilizando o método do vermelho neutro e MTT. Para a avaliação preliminar da nanotoxicidade foi realizado o estudo in vivo utilizando o peixe zebra. Nos estudos de internalização in vitro das nanopartículas utilizando as linhagens tumorais MDA-MB 231 e PC3 foi possível verificar qualitativamente a internalização das AuNPs. Os ensaios de radiomarcação das EGCG-AuNPs e EGCG-AuNPs-ASHɣ precisam ser otimizados quanto à estabilidade e pureza radioquímica. A nanotecnologia verde provou ser uma ferramenta valiosa na síntese de nanopartículas de ouro em relação à toxicidade, não exigindo etapas de eliminação de solventes e substâncias potencialmente tóxicas. Gold nanoparticles (AuNPs) have been studied to meet the needs of nanocarrier systems in cancer therapy and diagnosis. They can be used to target and release drugs at specific cell sites or groups, act as radiosensitizers, and in photothermal therapies as a heat-generating agent. A significant number of studies used its possible applications, such as biosensors, contrast in biological images, drug delivery systems, and cancer therapy and diagnosis. Thus, gold nanoparticles are considered as promising in the development of new compounds with potential application in cancer medicine, in the treatment of chronic inflammation, diseases, degenerative and autoimmune diseases. However, although the nanometric forms of gold are less toxic compared to many other nanomaterials, the toxicity of these particles must be thoroughly evaluated. The biggest challenge is to propose a method to functionalize the surface of the nanoparticles, and thus modulate their pharmacokinetics and pharmacodynamics, in addition to meeting the toxicity requirements for approval and application of nano biomaterials. The objective of this study was to develop a method of synthesis of gold nanoparticles (AuNPs) with potential application as nano biomaterials in cancer therapy and diagnosis (theranostic). For this purpose, the concept of green nanotechnology was used, in which phytochemical compounds with reducing potential were used in the preparation of AuNPs. A method of AuNPs functionalization was also established through recovery with bovine and human serum albumin using ionizing radiation. The importance of albumin coating is equal to a protein of this protein with GP60 receptors, which are found in several tumor cells, in addition to contributing in several relational cells to the kinetics of gold nanoparticles. The physico-chemical characterization of AuNPs and the reproducibility of the method was evaluated based on characterization tests performed by the techniques of UV-Vis / Fluorescence spectrophotometry, dynamic light scattering (DLS), Zeta potential, transmission electron microscopy (MET), inductively coupled plasma optical emission spectrometry (ICP-OES) and gel electrophoresis (SDS-PAGE). Stability was evaluated by means of temperature, pH, NaCl concentration, PBS, a solution containing amino acids, and DMEM cell culture medium without and with fetal bovine serum supplementation. The cell lines used were human prostate cancer (PC3), human breast adenocarcinoma (MDA-MB 231) and male Chinese hamster lung tissue cells (V79-4). In the recommendations tested as AuNPs, they did not show cytotoxicity in vitro using the neutral red method and MTT. For a preliminary assessment of nanotoxicity, an in vivo study using zebrafish was performed. In the in vitro internalization studies of the nanoparticles using the tumor lines MDA-MB 231 and PC3 it was possible to qualitatively verify the internalization of AuNPs. The radiolabeling assays for EGCG-AuNPs and EGCG-AuNPs-ASHɣ need to be optimized for radiochemical stability and purity. Green nanotechnology has proven to be a valuable tool in the synthesis of gold nanoparticles with lower toxicity, requiring no steps to eliminate solvents and potentially toxic substances.

CNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico FAPEMIG - Fundação de Amparo à Pesquisa do Estado de Minas Gerais CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior Radioactive nanoparticles (radio-NPs) functionalized with tumor specific biomolecules, injected intratumorally, have been reported as an alternative to low dose rate (LDR) seed based brachytherapy (BT). In radiation based cancer treatments accurate estimation of absorbed dose is crucial for proper disease control and to minimize the risk of radiation induced side effects. Currently, used Medical Internal Radiation Dose (MIRD) formalism for internal dosimetry purposes do not consider the impact of uptake and washout of radiopharmaceutical on the cell survival fraction (SF) and absorbed dose estimation. The single cell dosimetry (SCD), based on MIRD formalism, is generally used to evaluate the dosimetric characteristics of radionuclides for theranostic applications. However, there exists discrepancies in the graphical methods and radial energy distribution, used to estimate the dose distribution. Moreover, precise modeling of radiation transport in the medium by Monte Carlo (MC) codes plays a pivotal role in the estimation of absorbed dose. The dose point kernel (DPK) are used to: (i) test the accuracy of different Monte Carlo (MC) codes, by performing comparison in terms of DPK; and (ii) estimate 3D-absorbed dose in nuclear medicine. However, as per our knowledge the impact differences in DPK on absorbed dose was not investigated. This PhD project aims to perform dosimetry of LDR BT applications, using radio-NPs, and fill the above mentioned gaps in literature using MC methods. The dosimetric calculations were performed using two widely used MC codes: Geant4-DNA and EGSnrc. Initially, the comparison in terms of DPK for electrons in energy range of 1 keV to 3 MeV was made to test the accuracy of both codes. After validation, SCD approach was used to evaluate the dosimetric characteristics of 12 alpha/beta/auger emitting radionuclides for theranostic applications. The concept of radial dose function was also proposed for graphical representation of dose distribution. Further, the cell survival curves published in literature were replicated using the mathematical model proposed by Sefl et al. 2016. Our findings show that, both Geant4-DNA and EGSnrc can accurately simulate the transport of low energy electrons with respect to other MC codes. Moreover, the largest differences between DPKs were found for electron energies below 10 keV, which resulted in inhomogeneous dose distribution in micrometer and no impact on millimeter sized voxels. The alpha emitters were found to deposit highest absorbed dose in comparison to auger and beta emitters. Furthermore, we effectively replicated the cell survival curves published in literature on the use of radio-NPs for LDR BT applications. It was concluded that the accuracy of the MC codes and MC parameters must be validated and benchmarked before using them for dosimetry purposes. Also, the accurate knowledge of uptake rate, washout rate of NPs, radio-sensitivity and tumour repopulation rate is important for the calculation of cell survival curves. Nanopartículas radioativas (radio-NPs) funcionalizadas com biomoléculas específicas do tumor, injetadas de forma intratumoral, têm sido relatadas como uma alternativa à braquiterapia à base de sementes (LDR) de baixa taxa de dose (LDR). Em tratamentos de câncer à base de radiação a estimativa precisa da dose absorvida é crucial para o controle adequado da doença e para minimizar o risco de efeitos colaterais induzidos por radiação. Atualmente, o formalismo da Dose de Radiação Interna Médica (MIRD) usado para fins de dosimetria interna não considera o impacto da absorção e lavagem de radiofarmacêuticos na fração de sobrevivência celular (FS) e estimativa de dose absorvida. A dosimetria celular única (SCD), baseada no formalismo MIRD, é geralmente usada para avaliar as características dosimétricas dos radionuclídeos para aplicações teranósticas. No entanto, existem discrepâncias nos métodos gráficos e na distribuição de energia radial, utilizadas para estimar a distribuição da dose. Além disso, a modelagem precisa do transporte de radiação no meio pelos códigos de Monte Carlo (MC) desempenha um papel fundamental na estimativa da dose absorvida. O núcleo de ponto de dose (DPK) é usado para: (i) testar a precisão de diferentes códigos de Monte Carlo (MC), realizando comparação em termos de DPK; e (ii) estimam a dose absorvida por 3D na medicina nuclear. No entanto, pelo que sabemos, não foram investigadas as diferenças de impacto na DPK na dose absorvida. Este projeto de doutorado tem como objetivo realizar a dosimetria de aplicações LDR BT, utilizando radio-NPs, e preencher as lacunas acima mencionadas na literatura usando métodos de Monte Carlo (MC). Os cálculos dosimétricos foram realizados utilizando-se dois códigos MC amplamente utilizados: Geant4-DNA e EGSnrc. Inicialmente, a comparação em termos de DPK para elétrons na faixa de energia de 1 keV a 3 MeV foram realizadas para testar a precisão de ambos os códigos. Após a validação, utilizou-se a abordagem SCD para avaliar as características dosimétricas de emissão dos radionuclídeos de 12 alfa/beta/auger para aplicações teranósticas. Também foi proposto o conceito de função de dose radial para representação gráfica da distribuição de doses. Além disso, as curvas de sobrevivência celular publicadas na literatura foram replicadas utilizando-se o modelo matemático proposto por Sefl et al. 2016. O nosso trabalho apresenta que, tanto o Geant4-DNA quanto o EGSnrc podem simular com precisão o transporte de elétrons de baixa energia em relação a outros códigos MC. Além disso, as maiores diferenças entre as DPKs foram encontradas para energias eletrônicas abaixo de 10 keV, o que resultou na distribuição de dose homogênea em micrômetros e sem impacto em voxels em tamanhos milimétricos. Os emissores alfas foram encontrados para depositar a dose mais alta absorvida em comparação com os emissores auger e beta. Além disso, replicamos efetivamente as curvas de sobrevivência celular publicadas na literatura sobre o uso de radio-NPs para aplicações LDR BT. Concluiu-se que a precisão dos códigos MC e parâmetros MC deve ser validada e referenciada antes de usá-los para fins de dosimetria. Além disso, o conhecimento preciso da taxa de absorção, taxa de lavagem de NPs, radio-sensibilidade e taxa de repopulação de tumores é importante para o cálculo das curvas de sobrevivência celular. Keywords: Braquiterapia LDR, nanopartículas radioativas, núcleos de ponto de dose, métodos de Monte Carlo.