Fernanda S. Teixeira

Melanoma is originated from the malignant transformation of the melanocytes and is characterized by a high rate of invasion, the more serious stage compromising deeper layers of the skin and eventually leading to the metastasis. A high mortality due to melanoma lesion persists because most of melanoma lesions are detected in advanced stages, which decreases the chances of survival. The identification of the principal mechanics implicated in the development and progression of melanoma is essential to devise new early diagnosis strategies. Cell mechanics is related with a lot of cellular functions and processes, for instance motility, differentiation, migration and invasion. In particular, the elastic modulus (Young's modulus) is a very explored parameter to describe the cell mechanical properties; most cancer cells reported in the literature smaller elasticity modulus. In this work, we show that the elastic modulus of melanoma cells lacking galectin-3 is significantly lower than those of melanoma cells expressing galectin-3. More interestingly, the gradient of elastic modulus in cells from the nuclear region towards the cell periphery is more pronounced in shGal3 cells.

Thin films of two alloys (chromel and alumel), with thickness less than 100 nm, were obtained by plasma deposition technique, namely filtered cathodic vacuum arc (FCVA). The elemental analyses were performed by quantitative energy dispersive spectroscopy (EDS) microanalysis and Rutherford backscattering spectrometry (RBS). The applicability of EDS to such thin films as these was established by analysis of films deposited on substrates of different atomic numbers, specifically vitreous carbon, silicon, copper, and tin. We found that a substrate with atomic number similar to the mean atomic number of the film constituents is best for reliable EDS results, when compared to RBS. The compatibility between quantitative EDS measurements and RBS measurements, as well as comparison between the thin film elemental composition and the bulk material composition, was assessed by statistical analysis. Good consistency between EDS and RBS measurements was found for both chromel and alumel thin films when copper was used as substrate material. We observed severely overlapping peaks in the RBS output for the case of alumel films so that EDS analysis was crucial. We also compared thickness measurements determined by EDS and RBS, and we found good agreement for the case of alumel film on copper substrate, and 15% agreement for chromel film on copper substrate.

The intravascular parasitic worm Schistosoma mansoni is a causative agent of schistosomiasis, a disease of great global public health significance. Praziquantel is the only drug available to treat schistosomiasis and there is an urgent demand for new anthelmintic agents. Adopting a phenotypic drug screening strategy, here, we evaluated the antiparasitic properties of 46 commercially available cardiovascular drugs against S. mansoni. From these screenings, we found that amiodarone, telmisartan, propafenone, methyldopa, and doxazosin affected the viability of schistosomes in vitro, with effective concentrations of 50% (EC₅₀) and 90% (EC₉₀) values ranging from 8 to 50 µM. These results were further supported by scanning electron microscopy analysis. Subsequently, the most effective drug (amiodarone) was further tested in a murine model of schistosomiasis for both early and chronic S. mansoni infections using a single oral dose of 400 mg/kg or 100 mg/kg daily for five consecutive days. Amiodarone had a low efficacy in chronic infection, with the worm and egg burden reduction ranging from 10 to 30%. In contrast, amiodarone caused a significant reduction in worm and egg burden in early infection (>50%). Comparatively, treatment with amiodarone is more effective in early infection than praziquantel, demonstrating the potential role of this cardiovascular drug as an antischistosomal agent.

Nanocomposites formed by metal nanoparticles self‐assembled in an insulator matrix are of great technological importance. Applications include surface enhanced Raman spectroscopy based biosensors, optical devices, photovoltaic cells, and more. Self‐assembling of nanocomposites using low energy ion implantation offers a fast and low cost process. We report here on our work on nanocomposites formed by very low energy ion implantation of gold and platinum nanoparticles into Poly(methyl methacrylate) (PMMA), with description of the nanoparticle evolution as a function of implantation dose. The Au‐PMMA and Pt‐PMMA nanocomposites were characterized by transmission electron microscopy, thus determining the nanoparticle density, their size distribution, and the distance between particles as a function of implantation dose. A comparison between Au‐PMMA and Pt‐PMMA reveals substantial differences in the formation processes of the nanoparticles. The results provide insight into basic nanoparticle formation processes, as well as crucial information important for design applications. In addition, the tunneling decay length ξ and the electron affinity ε of the implantation‐modified PMMA were obtained using a new and simple approach.

Viruses can spread to the environment, and it can be challenging to clear it. A direct approach to limit airborne transmission of pathogens in dental clinic offices is to inactivate viruses within a short time of their production and block the person-to-person transmission routes in dental clinics. For this, we can use chemical substances on surfaces and germicidal ultraviolet light (UV), typically at 254 nm, for complementary disinfection of surfaces and air contaminated by aerosols produced by high-speed handpiece or ultrasound scaler. Based on the literature review and the similarity of Sars-Cov-2 with other previously studied corovaviruses, COVID-19 is sensitive to UV irradiation that can break the genome of this virus, inactivating it. In our study, we performed the calculation of the time required to decontaminate a dental care room between each patient change. We can conclude that the use of UVC can be incorporated into the dental care routine to reduce cross contamination.KeywordsUVC-decontamination; Sterilization; Ultraviolet light; Dentistry; Sars-Cov-2.

In this work, we present some properties and use of a nanocomposite formed by gold nanoparticles (NPs) into poly(methyl methacrylate) (PMMA) and its application as substrates for surface-enhanced Raman spectroscopy (SERS). The nanocomposite was formed using low-energy (49 eV) ion implantation of gold in PMMA using a cathodic arc plasma gun. The gold NPs are formed spontaneously from the implanted ions and they remain isolated from each other by the polymer medium surrounding them, ensuring a spacing between the NPs of less than 10 nm (hot spot places). The NPs form below the surface, protected from the environment, guaranteeing the stability of the composite layer. Moreover, here, we present an interesting approach to concentrate analyte molecules closer to the metal surface using the swelling effect in PMMA. Using absorption of the analyte, the molecules stay in the gaps between NPs, which is a good solution for one of the biggest challenges in SERS, that is, to guide molecules to the hot spot places.

Schistosomiasis is a parasitic flatworm disease that infects over 200 million people worldwide, especially in poor communities. Treatment and control of the disease rely on just one drug, praziquantel. Since funding for drug development for poverty-associated diseases is very limited, drug repurposing is a promising strategy. In this study, from a screening of 13 marketed diuretics, we identified that spironolactone, a potassium-sparing diuretic, had potent antischistosomal effects on Schistosoma mansoniin vitro and in vivo in a murine model of schistosomiasis. In vitro, spironolactone at low concentrations (< 10 µM) is able to alter worm motor activity and the morphology of adult schistosomes, leading to parasitic death. In vivo, oral treatment with spironolactone at a single dose (400 mg/kg) or daily for five consecutive days (100 mg/kg/day) in mice harbouring either patent or pre-patent infections significantly reduced worm burden, egg production, and hepato- and splenomegaly (PP<0.001). Taken together with the safety profile of spironolactone, supported by its potential to affect schistosomes, these results indicate that spironolactone could be a potential treatment for schistosomiasis and make it promising for re-purposing.

In this study, we evaluated the in vitro and in vivo schistosomicidal activities of chalcones against Schistosoma mansoni worms. In vitro assays revealed that chalcones 1 and 3 were the most active compounds, without affecting significantly mammalian cells. Confocal laser scanning microscopy and scanning electron microscopy studies revealed reduction on the numbers of tubercles and morphological alterations in the tegument of S. mansoni worms after in vitro incubation with chalcones 1 and 3. In a mouse model of schistosomiasis, the oral treatment (400 mg/kg) with chalcone 1 or 3 significantly caused a total worm burden reduction in mice. Chalcone 1 showed significant inhibition of the S. mansoni ATP diphosphohydrolase activity, which was corroborated by molecular docking studies. The results suggested that chalcones could be explored as lead compounds with antischistosomal properties.