Effects of Zn-ZnO Core-Shell Nanoparticles on Antimicrobial Mechanisms and Immune Cell Activation.

The deposition of zinc-zinc oxide nanoparticles (Zn-ZnO NPs) onto porous Ta2O5 surfaces enriched with calcium phosphate by DC magnetron sputtering was investigated to improve the surface antimicrobial activity without triggering an inflammatory response. Different sizes and amounts of Zn NPs obtained by two optimized different depositions and an additional thin carbon (C) layer deposited over the NPs were explored. The deposition of the Zn NPs and the C layer mitigates the surface porosity, increasing the surface hydrophobicity and decreasing the surface roughness. The possible antimicrobial effect and immune system activation of Zn-ZnO NPs were investigated in Candida albicans and macrophage cells, respectively. It was found that the developed surfaces displayed a fungistatic behavior, as they impair the growth of C. albicans between 5 and 24 h of culture. This behavior was more evident on the surfaces with bigger NPs and the highest amounts of Zn. The same trend was observed in both reactive oxygen species (ROS) generation and loss of C. albicans' membrane integrity. After 24 h of culture, cell toxicity was also dependent on the amount of the NPs. Cell toxicity was observed in surfaces with the highest amount of Zn NPs and with the C layer, while cells were able to grow without any signs of cytotoxicity in the porous surfaces with the lowest amount of NPs. The same Zn-dose-dependent behavior was noticed in the TNF-α production. The Zn-containing surfaces show a vastly inferior cytokine secretion than the lipopolysaccharide (LPS)-stimulated cells, indicating that the modified surfaces do not induce an inflammatory response from macrophage cells. This study provides insights for understanding the Zn amount threshold that allows a simultaneous inhibition of the fungi growth with no toxic effect and the main antimicrobial mechanisms of Zn-ZnO NPs, contributing to future clinical applications.

Antimicrobial Polymeric Surfaces Using Embedded Silver Nanoparticles.

Pathogens (disease-causing microorganisms) can survive up to a few days on surfaces and can propagate through surfaces in high percentages, and thus, these surfaces turn into a primary source of pathogen transmission. To prevent and mitigate pathogen transmission, antimicrobial surfaces seem to be a promising option that can be prepared by using resilient, mass-produced polymers with partly embedded antimicrobial nanoparticles (NPs) with controlled size. In the present study, a 6 nm thick Ag nanolayer was sputter deposited on polycarbonate (PC) substrate and then thermally annealed, in a first step at 120 °C (temperature below Tg) for two hours, for promoting NP diffusion and growth, and in a second step at 180 °C (temperature above Tg) for 22 h, for promoting thermal embedding of the NPs into the polymer surface. The variation in the height of NPs on the polymer surface with thermal annealing confirms the embedding of NPs. It was shown that the incorporation of silver nanoparticles (Ag NPs) had a great impact on the antibacterial capacity, as the Ag NP-embedded polymer surface presented an inhibition effect on the growth of Gram-positive and Gram-negative bacteria. The tested surface-engineering process of incorporating antimicrobial Ag NPs in a polymer surface is both cost-effective and highly scalable.

A Decade of Progress on MAO-Treated Tantalum Surfaces: Advances and Contributions for Biomedical Applications.

Micro-structured coatings with functional properties have been investigated due to a wide range of applications. It is known that micro-structures can play an important role in surface interactions determining the materials' performance. Amongst the other materials, there has been an increasing interest in tantalum oxide (Ta2O5). This attention is mainly due to its variety of properties: biocompatibility and bioactivity; high dielectric constant; good thermal and chemical stability; excellent corrosion and mechanical resistance. Moreover, there is a wide range of applications in which the properties can be fitted. Furthermore, according to the final application, these properties can be enhanced or tailored through surface micro-structures manipulation. Due to this purpose, over the past decade, Ta surface modification by micro-arc oxidation (MAO) has been investigated mostly for biomedical applications. Therefore, this review focuses on Ta surface functionalization using the MAO technique. A clear understanding of the micro-discharge phenomena and the formation mechanism of a Ta2O5 anodic coating by MAO is supplied. The Ta2O5 coating morphology, topography, chemistry, and structure are explored, establishing their correlation with the MAO parameters. Additionally, an understanding of Ta2O5's biological, mechanical, and electrochemical properties is provided and reviewed.

Porous tantalum oxide with osteoconductive elements and antibacterial core-shell nanoparticles: A new generation of materials for dental implants.

Implant surfaces with cytocompatible and antibacterial properties are extremely desirable for the prevention of implant's infection and the promotion of osseointegration. In this work, both micro-arc oxidation (MAO) and DC magnetron sputtering techniques were combined in order to endow tantalum-based surfaces with osteoblastic cytocompatibility and antibacterial activity. Porous Ta2O5 layers containing calcium (Ca) and phosphorous (P) were produced by MAO (TaCaP) to mimic the bone tissue morphology and chemical composition (Ca/P ratio close to 1.67). Furthermore, zinc (Zn) nanoparticles were deposited onto the previous surfaces by DC magnetron sputtering without or with an additional thin carbon layer deposited over the nanoparticles (respectively, TaCaP-Zn and TaCaP-ZnC) to control the Zn ions (Zn2+) release. Before osteoblastic cell seeding, the surfaces were leached for three time-points in PBS. All modified samples were cytocompatible. TaCaP-Zn slightly impaired cell adhesion but this was improved in the samples leached for longer immersion times. The initial cell adhesion was clearly improved by the deposition of the carbon layer on the Zn nanoparticles, which also translated to a higher proliferation rate. Both Zn-containing surfaces presented antibacterial activity against S. aureus. The two surfaces were active against planktonic bacteria, and TaCaP-Zn also inhibited sessile bacteria. Attributing to the excellent in vitro performance of the nanostructured Ta surface, with osteoconductive elements by MAO followed by antimicrobial nanoparticles incorporation by magnetron sputtering, this work is clearly a progress on the strategy to develop a new generation of dental implants.

Recurrent pyogenic granuloma associated with port-wine stain: a case report / Granuloma Piogênico recorrente associado à Mancha Vinho do Porto: um relato de caso

O granuloma piogênico (GP) é um processo proliferativo não neoplásico. Este termo entretanto, é equivocado, uma vez que não está relacionado a qualquer infecção, não contém pus e não é um verdadeiro granuloma. A ocorrência do GP recorrente associado a lesões vasculares na pele, tais como manchas de vinho do porto, tem sido descrita na literatura. Paciente do gênero masculino com 23 anos de idade foi atendido na Universidade Federal do Maranhão apresentando uma lesão com características de granuloma piogênico na vestibular do primeiro molar, associada à mancha vinho do porto. O diagnóstico foi confirmado através de biopsia excisional e análise histopatológica. Devido à recorrência da lesão após a abordagem cirúrgica, injeções intralesionais de corticoides foram realizadas três vezes. Após dois anos de acompanhamento, não houve recorrência. Pode-se concluir que, apesar da alta prevalência de recorrência do granuloma piogênico, injeções intralesionais com corticoides podem ser uma alternativa ao tratamento cirúrgico convencional.

Pyogenic granuloma (PG) is a non-neoplastic proliferative lesion. This term, however, is a misconception, since it is not related to any infection, does not contain pus and it is not a true granuloma. The occurrence of recurrent PG associated with vascular lesions on the skin, such as port-wine stains, has been described in the literature. A 23 years old male patient was attended in the Federal University of Maranhão presenting a lesion with pyogenic granuloma characteristics in the buccal side of the first molar associated with port-wine stain. The diagnosis was confirmed per an excisional biopsy, along with histopathologic analysis. Due to the recurrence of the lesion after the surgical approach, intralesional corticosteroid injections was performed three times. After two-years no signs of recurrence could be observed. In conclusion, despite of the high prevalence of Pyogenic Granuloma recurrence, intralesional corticosteroid injections may be an alternative option to conventional surgical treatment.

Effects of hyperleptinemia in rat saliva composition, histology and ultrastructure of the major salivary glands.

OBJECTIVE: To study the effect of the satiety hormone, leptin, in saliva proteome and salivary gland histology and ultrastructure. DESIGN: Increases in blood leptin levels were induced through mini-pump infusion in male Wistar rats, during a period of 7 days. Saliva was collected before and at the end of the experimental period, for proteomic analysis, and major salivary glands were collected, at the end, for biochemical, histological and ultrastructural analysis. RESULTS: Immunohistochemistry revealed the presence of leptin receptors in major salivary glands. Salivary amylase levels and enzymatic activity were decreased in saliva, whereas the enzymatic activity of this protein was increased in the cytosol of parotid gland cells. Transmission electron microscopy allowed the observation of high number of electron-dense granules in cytosol of parotid acinar cells, from leptin treated animals. CONCLUSIONS: Increased levels of plasmatic leptin result in changes in saliva composition and salivary glands function. To our knowledge, this is the first study providing evidences for a potential role of leptin in salivary gland secretion and saliva composition. An understanding of how appetite/satiety factors influence saliva composition and how this composition influences food processing in mouth may be relevant in understanding ingestivebehaviour.

Intervenção educacional no gerenciamento de resíduos com base na odontologia sustentável / Educational intervention in management of waste based at sustainable odontology

O presente trabalho objetivou avaliar o efeito de uma intervenção educacional sobre a classe acadêmica odontológica a respeito do gerenciamento dos resíduos sólidos de saúde e a prática de condutas sustentáveis. Foram aplicados questionários, em dois momentos, a respeito dos conhecimentos e atitudes dos acadêmicos. Entre os tempos de avaliação, foram ministradas palestras e diversas ações educativas sobre métodos de gerenciamento e atitudes sustentáveis, também foram colocadas lixeiras plásticas devidamente identificadas nas clínicas da faculdade. Evidenciou-se o déficit na formação dos graduandos sobre o tema, sendo que após a intervenção houve aumento de práticas corretas de destinação dos resíduos gerados durante atividades clínicas. Conclui-se que a intervenção educacional foi eficaz na contribuição do aprendizado e na mudança do modo de agir, com maior engajamento em atividades sustentáveis

The aim of this study was to evaluate the effect of an educational intervention on the dental academic class regarding the management of solid waste’s health and sustainable conduct. Questionnaires were applied in two stages, about the knowledge and attitudes of students. Between the evaluation’ s time, lectures and various educational actions on management attitudes and sustainable methods were given, were also placed properly identified plastic bins in college clinics. It was evident the deficit in the education of students on the topic, and after the intervention there was an increase of correct practices of allocation of waste generated during clinical activities. We conclude that educational intervention was effective in learning and in the change in the attitude of students, with greater engagement in sustainable activities