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1.
Biology (Basel) ; 11(3)2022 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-35336761

RESUMO

Protein Engineering is a highly evolved field of engineering aimed at developing proteins for specific industrial, medical, and research applications. Here, we present a practical teaching course to demonstrate fundamental techniques used to express, purify and analyze a recombinant protein produced in Escherichia coli-the enhanced green fluorescent protein (eGFP). The methodologies used for eGFP production were introduced sequentially over six laboratory sessions and included (i) bacterial growth, (ii) sonication (for cell lysis), (iii) affinity chromatography and dialysis (for eGFP purification), (iv) bicinchoninic acid (BCA) and fluorometry assays for total protein and eGFP quantification, respectively, and (v) sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) for qualitative analysis. All groups were able to isolate the eGFP from the cell lysate with purity levels up to 72%. Additionally, a mass balance analysis performed by the students showed that eGFP yields up to 46% were achieved at the end of the purification process following the adopted procedures. A sensitivity analysis was performed to pinpoint the most critical steps of the downstream processing.

2.
Saúde debate ; 46(132): 240-251, jan.-mar. 2022.
Artigo em Português | LILACS-Express | LILACS | ID: biblio-1361150

RESUMO

RESUMO A pandemia do novo coronavírus afetou a dinâmica do cotidiano escolar, obrigando os(as) professores(as) a um movimento de adaptação para dar conta das demandas impostas pelo distanciamento social. Esse cenário também atingiu as pesquisas, cujas técnicas de coletas de dados se davam de maneira presencial e tiveram que ser realizadas remotamente. O objetivo deste texto é descrever a trajetória da Comunidade Ampliada de Pesquisa, adaptada para o ambiente virtual (CAP on-line), como parte da pesquisa que buscou examinar as novas exigências do ensino remoto e suas implicações para a saúde dos(as) professores(as). Foram realizadas três oficinas com a participação de professores(as) do Ensino Fundamental e Médio. Observou-se que o processo de pesquisa tem correlações com os próprios resultados do estudo, especialmente no que se refere aos novos aprendizados trazidos pelo ensino remoto. Conclui-se que o compartilhamento de experiências de trabalho por meio da CAP on-line é uma possibilidade. No entanto, o aperfeiçoamento nos modos de interação virtual, o domínio do aparato tecnológico e o acesso a equipamentos de qualidade são elementos a serem observados para o aperfeiçoamento dessa abordagem coletiva de investigação.


ABSTRACT The new Coronavirus pandemic has affected the dynamics of everyday school life, forcing teachers to adapt to the demands imposed by social distancing. This scenario also involved the surveys, whose data collection techniques took place in person and had to be carried out remotely. This text aims to describe the trajectory of the expanded research community, adapted to the virtual format, as part of the research that sought to examine the new requirements of remote teaching and its implications for teachers' health. Three workshops were held with the participation of elementary and high school teachers. It was observed that the research process has correlations with the results of the study, especially concerning new learning brought by remote learning. It is concluded that sharing work experiences through online CAP is a possibility. However, the improvement in the modes of virtual interaction, mastery of the technological apparatus, and access to quality equipment are elements to be observed in order to improve this collective approach to investigation.

3.
Nanomaterials (Basel) ; 12(3)2022 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-35159699

RESUMO

The increasing incidence of implant-associated infections has prompted the development of effective strategies to prevent biofilm formation on these devices. In this work, pristine graphene nanoplatelet/polydimethylsiloxane (GNP/PDMS) surfaces containing different GNP loadings (1, 2, 3, 4, and 5 wt%) were produced and evaluated on their ability to mitigate biofilm development. After GNP loading optimization, the most promising surface was tested against single- and dual-species biofilms of Staphylococcus aureus and Pseudomonas aeruginosa. The antibiofilm activity of GNP/PDMS surfaces was determined by the quantification of total, viable, culturable, and viable but nonculturable (VBNC) cells, as well as by confocal laser scanning microscopy (CLSM). Results showed that 5 wt% GNP loading reduced the number of total (57%), viable (69%), culturable (55%), and VBNC cells (85%) of S. aureus biofilms compared to PDMS. A decrease of 25% in total cells and about 52% in viable, culturable, and VBNC cells was observed for P. aeruginosa biofilms. Dual-species biofilms demonstrated higher resistance to the antimicrobial activity of GNP surfaces, with lower biofilm cell reductions (of up to 29% when compared to single-species biofilms). Still, the effectiveness of these surfaces in suppressing single- and dual-species biofilm formation was confirmed by CLSM analysis, where a decrease in biofilm biovolume (83% for S. aureus biofilms and 42% for P. aeruginosa and dual-species biofilms) and thickness (on average 72%) was obtained. Overall, these results showed that pristine GNPs dispersed into the PDMS matrix were able to inhibit biofilm growth, being a starting point for the fabrication of novel surface coatings based on functionalized GNP/PDMS composites.

4.
Eng. sanit. ambient ; 27(1): 91-101, jan.-fev. 2022. tab, graf
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-1364817

RESUMO

ABSTRACT The high consumption of water and the generation of greywater in laundromats underscore the need to investigate advanced treatment techniques to reuse this effluent. Based on the estimated growth figures of the laundromat sector in Brazil, this study looked into the efficiency of electrocoagulation to treat laundromat greywater. Electrodes were connected to an EC reactor on a monopolar parallel connection mode, with electric current of 6 A and current density of 400 A.m2. The highest efficiency to treat laundromat greywater was observed at a distance of 15 mm between electrodes, voltage of 17.14 V, and operation time of 30 min, when the removal values of apparent color, true color, turbidity, biochemical oxygen demand, chemical oxygen demand, and surfactants were 92, 97, 88, 91, 98, and 96%, respectively. Electrode consumption was measured at 1.82 g.h, while energy consumption was 20.54 kWh.m3 and the total cost was US$ 4.10 per cubic meter of treated effluent. However, despite the high efficiency of the treatment, reuse of treated laundromat effluent requires polishing in order to meet the standards defined by Brazilian regulations.


RESUMO O elevado consumo de água potável e a consequente geração de efluentes associados ao segmento de lavanderias domésticas justificam o estudo de tratamentos avançados que proporcionem o reuso dessas águas. Considerando-se uma perspectiva de crescimento desse setor em nível nacional, esta pesquisa avaliou a eletrocoagulação como tecnologia de tratamento de tais efluentes. Foram executados testes de bancada utilizando eletrodos em alumínio, arranjados como monopolar paralelo. A corrente elétrica e a densidade de corrente foram fixadas em 6A e 400A.m², respectivamente. Entre as variáveis avaliadas estão a distância entre eletrodos, o tempo de operação, o tipo de roupa, a utilização de alvejante e o suporte para eletrólise. O melhor tratamento foi obtido sem a utilização do suporte para eletrólise, para uma distância entre eletrodos de 15 mm, tensão elétrica aplicada no sistema de 17,14 V e tempo de operação igual a 30 min. Nessas condições, as eficiências do tratamento obtidas foram de 92% para cor aparente, 97% para cor verdadeira, 88% para turbidez, 91% para demanda bioquímica de oxigênio, 98% para demanda química de oxigênio e 96% para surfactantes. O sistema resultou no consumo de eletrodo de 1,83 g.h e no consumo de energia elétrica igual a 20,57 kWh.m³. O custo final do tratamento foi calculado em US$ 4,10.m³ de efluente tratado. Embora tenham sido obtidas elevadas remoções nas concentrações dos poluentes, para o reuso do efluente ainda é necessário um tratamento adicional.

5.
Curr Microbiol ; 79(2): 57, 2022 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-34982247

RESUMO

Leptospirosis is a worldwide zoonosis and a serious public health threat in tropical and subtropical areas. The etiologic agents of leptospirosis are pathogenic spirochetes from the genus Leptospira. In severe cases, patients develop a pulmonary hemorrhage that is associated with high fatality rates. Several animal models were established for leptospirosis studies, such as rodents, dogs, and monkeys. Although useful to study the relationship among Leptospira and its hosts, the animal models still exhibit economic and ethical limitation reasons and do not fully represent the human infection. As an attempt to bridge the gap between animal studies and clinical information from patients, we established a three-dimensional (3-D) human lung cell culture for Leptospira infection. We show that Leptospira is able to efficiently infect the cell lung spheroids and also to infiltrate in deeper areas of the cell aggregates. The ability to infect the 3-D lung cell aggregates was time-dependent. The 3-D spheroids infection occurred up to 120 h in studies with two serovars, Canicola and Copenhageni. We standardized the number of bacteria in the initial inoculum for infection of the spheroids and we also propose two alternative culture media conditions. This new approach was validated by assessing the expression of three genes of Leptospira related to virulence and motility. The transcripts of these genes increased in both culture conditions, however, in higher rates and earlier times in the 3-D culture. We also assessed the production of chemokines by the 3-D spheroids before and after Leptospira infection, confirming induction of two of them, mainly in the 3-D spheroids. Chemokine CCL2 was expressed only in the 3-D cell culture. Increasing of this chemokine was observed previously in infected animal models. This new approach provides an opportunity to study the interaction of Leptospira with the human lung epithelium in vitro.


Assuntos
Leptospira , Leptospirose , Animais , Humanos , Leptospirose/veterinária , Pulmão , Virulência
6.
Interface (Botucatu, Online) ; 26: e210318, 2022.
Artigo em Português | LILACS-Express | LILACS | ID: biblio-1356351

RESUMO

O objetivo principal do presente artigo consiste em problematizar aspectos do processo de trabalho de professore(a)s da educação básica do estado do Rio de Janeiro, no contexto pandêmico, e sua relação com a saúde, tomando por base registros diários de professore(a)s em cadernetas digitais. Trata-se de uma pesquisa social de cunho qualitativo e de natureza participativa, realizada em parceria com o sindicato dos professores de Macaé e região. Participaram do estudo oito professore(a)s das redes pública e particular de ensino. No que tange à análise dos materiais, adotou-se a técnica de análise temática, organizada em dois blocos temáticos principais de interpretação: o primeiro relaciona-se à análise do processo de trabalho (remoto) docente, já o segundo refere-se à saúde, comorbidades pregressas e resistências coletivas. Quanto aos resultados, sobressaiu que professores(a)s vivenciam o aprofundamento de formas de opressão, precarização e intensificação do trabalho.


The main aim of this study was to problematize health aspects of the work process of primary school teachers in the state of Rio de Janeiro in the context of the pandemic using daily entries made by teachers in digital notebooks. We conducted a qualitative participatory social study in partnership with the Macaé Teachers Union. Eight teachers from public and private schools participated in the study. The data were analyzed using thematic analysis and organized into two main categories: the first related to the analysis of the (remote) work process; and the second comprising health, previous comorbidities and collective resistance. The findings highlight that the teachers are experiencing the deepening of forms of oppression, worsening working terms and conditions, and work intensification.


El objetivo principal de este artículo es problematizar aspectos del proceso de trabajo de profesores y profesoras de la educación básica del Estado de Río de Janeiro, en el contexto pandémico y su relación con la salud, utilizando como base registros diarios de profesores y profesoras en cartillas digitales. Se trata de un estudio social de cuño cualitativo y de naturaleza participativa, realizado en alianza con el Sindicato de los profesores de Macaé y región. En el estudio participaron ocho profesores y profesoras de las redes pública y particular de enseñanza. En lo que se refiere al análisis de los materiales, se adoptó la técnica de análisis temático, organizado en dos bloques temáticos principales de interpretación: el primero se relaciona al análisis del proceso de trabajo (a distancia) docente; el segundo, se refiere a la salud, comorbilidades anteriores y resistencias colectivas. Con relación a los resultados, se subrayó que profesores y profesoras viven la profundización de formas de opresión, precarización e intensificación del trabajo.

7.
Curr. Microbiol., v. 70, p. 57, jan. 2022
Artigo em Inglês | Sec. Est. Saúde SP, SESSP-IBPROD, Sec. Est. Saúde SP | ID: bud-4095

RESUMO

Leptospirosis is a worldwide zoonosis and a serious public health threat in tropical and subtropical areas. The etiologic agents of leptospirosis are pathogenic spirochetes from the genus Leptospira. In severe cases, patients develop a pulmonary hemorrhage that is associated with high fatality rates. Several animal models were established for leptospirosis studies, such as rodents, dogs, and monkeys. Although useful to study the relationship among Leptospira and its hosts, the animal models still exhibit economic and ethical limitation reasons and do not fully represent the human infection. As an attempt to bridge the gap between animal studies and clinical information from patients, we established a three-dimensional (3-D) human lung cell culture for Leptospira infection. We show that Leptospira is able to efficiently infect the cell lung spheroids and also to infiltrate in deeper areas of the cell aggregates. The ability to infect the 3-D lung cell aggregates was time-dependent. The 3-D spheroids infection occurred up to 120 h in studies with two serovars, Canicola and Copenhageni. We standardized the number of bacteria in the initial inoculum for infection of the spheroids and we also propose two alternative culture media conditions. This new approach was validated by assessing the expression of three genes of Leptospira related to virulence and motility. The transcripts of these genes increased in both culture conditions, however, in higher rates and earlier times in the 3-D culture. We also assessed the production of chemokines by the 3-D spheroids before and after Leptospira infection, confirming induction of two of them, mainly in the 3-D spheroids. Chemokine CCL2 was expressed only in the 3-D cell culture. Increasing of this chemokine was observed previously in infected animal models. This new approach provides an opportunity to study the interaction of Leptospira with the human lung epithelium in vitro.

8.
Cien Saude Colet ; 26(12): 5925-5934, 2021 Dec.
Artigo em Português, Inglês | MEDLINE | ID: mdl-34909985

RESUMO

This study aimed to problematize aspects of the work of professors in relation to gender, assessment policies, and health. For this purpose, a qualitative social investigation was conducted within the aspect of participatory studies and the views of materialist feminism. An analysis of the material was carried out through content analysis, according to the topic, using four main themes: conflicts between professors' work and domestic work; professors' work, motherhood, and guilt; policies for the assessment of professors and gender relations; and the sexual division of labor and teaching. It was possible to perceive just how much the demands of the productive sphere have gone beyond the time of the workday and into the reproductive sphere and the private life of professors, compromising the struggle for health and leading to processes of suffering and illness. The theme of the sexual division of labor in public universities appears to be an important issue that highlights work overload and psychological illness, especially at a time when the teaching profession is becoming increasingly competitive. In conclusion, we believe that there is an imperative need for investments in public policies that can guarantee gender equality in higher education.


O objetivo do presente estudo foi problematizar aspectos do trabalho docente do ensino superior em relação a gênero, políticas de avaliação e saúde. Para tal, realizou-se uma pesquisa social de caráter qualitativo sob a vertente dos estudos participativos e do enfoque do feminismo materialista. A análise do material foi efetuada por meio da análise de conteúdo, na modalidade temática, e identificados quatro temas principais: conflitos entre trabalho docente e trabalho doméstico; trabalho docente, maternidade e culpa; políticas de avaliação do trabalho docente e relações de gênero; divisão sexual do trabalho e docência. Percebeu-se o quanto as demandas da esfera produtiva têm extrapolado o tempo da jornada de trabalho para a esfera reprodutiva e a vida privada das professoras, comprometendo a luta e a defesa pela saúde que podem levar a processos de sofrimento e adoecimento. O tema da divisão sexual do trabalho em universidades públicas desponta como importante questão que evidencia sobrecarga de trabalho e mal estar psíquico, especialmente em um momento em que o trabalho docente se torna crescentemente competitivo. Concluiu-se pela imperativa necessidade de investimentos em políticas públicas que garantam igualdade de gênero no trabalho do ensino superior.


Assuntos
Pessoal de Educação , Universidades , Ansiedade , Docentes , Humanos
9.
iScience ; 24(12): 103480, 2021 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-34927024

RESUMO

Despite the advancements in material science and surgical techniques, the incidence of implant-associated infections (IAIs) has increased significantly. IAIs are mainly caused by microbial adhesion and biofilm formation on implant surfaces. In this study, we aimed to evaluate and critically discuss the antimicrobial efficacy of chitosan-based coatings to prevent the occurrence of IAIs. For this purpose, a PRISMA-oriented systematic review was conducted based on predefined criteria and forty studies were selected for qualitative analysis. Results indicated that chitosan (CS) association with enzymes and antimicrobial peptides improves its antimicrobial activity and extends its use in a broad range of physiological conditions. Likewise, CS association with polymers resulted in enhanced antimicrobial and anti-adhesive coatings with desirable properties, such as biocompatibility and durability, for implantable medical devices (IMDs). These findings can assist researchers in the design of new CS coatings for application in IMDs.

10.
Antibiotics (Basel) ; 10(12)2021 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-34943738

RESUMO

The low efficacy of conventional treatments and the interest in finding natural-based approaches to counteract biofilm development on urinary tract devices have promoted the research on probiotics. This work evaluated the ability of two probiotic strains, Lactobacillus plantarum and Lactobacillus rhamnosus, in displacing pre-formed biofilms of Escherichia coli and Staphylococcus aureus from medical-grade silicone. Single-species biofilms of 24 h were placed in contact with each probiotic suspension for 6 h and 24 h, and the reductions in biofilm cell culturability and total biomass were monitored by counting colony-forming units and crystal violet assay, respectively. Both probiotics significantly reduced the culturability of E. coli and S. aureus biofilms, mainly after 24 h of exposure, with reduction percentages of 70% and 77% for L. plantarum and 76% and 63% for L. rhamnosus, respectively. Additionally, the amount of E. coli biofilm determined by CV staining was maintained approximately constant after 6 h of probiotic contact and significantly reduced up to 67% after 24 h. For S. aureus, only L. rhamnosus caused a significant effect on biofilm amount after 6 h of treatment. Hence, this study demonstrated the potential of lactobacilli to control the development of pre-established uropathogenic biofilms.

11.
Ciênc. Saúde Colet ; 26(12): 5925-5934, Dez. 2021.
Artigo em Inglês, Português | LILACS | ID: biblio-1350514

RESUMO

Resumo O objetivo do presente estudo foi problematizar aspectos do trabalho docente do ensino superior em relação a gênero, políticas de avaliação e saúde. Para tal, realizou-se uma pesquisa social de caráter qualitativo sob a vertente dos estudos participativos e do enfoque do feminismo materialista. A análise do material foi efetuada por meio da análise de conteúdo, na modalidade temática, e identificados quatro temas principais: conflitos entre trabalho docente e trabalho doméstico; trabalho docente, maternidade e culpa; políticas de avaliação do trabalho docente e relações de gênero; divisão sexual do trabalho e docência. Percebeu-se o quanto as demandas da esfera produtiva têm extrapolado o tempo da jornada de trabalho para a esfera reprodutiva e a vida privada das professoras, comprometendo a luta e a defesa pela saúde que podem levar a processos de sofrimento e adoecimento. O tema da divisão sexual do trabalho em universidades públicas desponta como importante questão que evidencia sobrecarga de trabalho e mal estar psíquico, especialmente em um momento em que o trabalho docente se torna crescentemente competitivo. Concluiu-se pela imperativa necessidade de investimentos em políticas públicas que garantam igualdade de gênero no trabalho do ensino superior.


Abstract This study aimed to problematize aspects of the work of professors in relation to gender, assessment policies, and health. For this purpose, a qualitative social investigation was conducted within the aspect of participatory studies and the views of materialist feminism. An analysis of the material was carried out through content analysis, according to the topic, using four main themes: conflicts between professors' work and domestic work; professors' work, motherhood, and guilt; policies for the assessment of professors and gender relations; and the sexual division of labor and teaching. It was possible to perceive just how much the demands of the productive sphere have gone beyond the time of the workday and into the reproductive sphere and the private life of professors, compromising the struggle for health and leading to processes of suffering and illness. The theme of the sexual division of labor in public universities appears to be an important issue that highlights work overload and psychological illness, especially at a time when the teaching profession is becoming increasingly competitive. In conclusion, we believe that there is an imperative need for investments in public policies that can guarantee gender equality in higher education.


Assuntos
Humanos , Universidades , Pessoal de Educação , Ansiedade , Docentes
13.
Microorganisms ; 9(9)2021 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-34576888

RESUMO

The early colonization of surfaces and subsequent biofilm development have severe impacts in environmental, industrial, and biomedical settings since they entail high costs and health risks. To develop more effective biofilm control strategies, there is a need to obtain laboratory biofilms that resemble those found in natural or man-made settings. Since microbial adhesion and biofilm formation are strongly affected by hydrodynamics, the knowledge of flow characteristics in different marine, food processing, and medical device locations is essential. Once the hydrodynamic conditions are known, platforms for cell adhesion and biofilm formation should be selected and operated, in order to obtain reproducible biofilms that mimic those found in target scenarios. This review focuses on the most widely used platforms that enable the study of initial microbial adhesion and biofilm formation under controlled hydrodynamic conditions-modified Robbins devices, flow chambers, rotating biofilm devices, microplates, and microfluidic devices-and where numerical simulations have been used to define relevant flow characteristics, namely the shear stress and shear rate.

14.
Antibiotics (Basel) ; 10(8)2021 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-34439016

RESUMO

Novel technologies to prevent biofilm formation on urinary tract devices (UTDs) are continually being developed, with the ultimate purpose of reducing the incidence of urinary infections. Probiotics have been described as having the ability to displace adhering uropathogens and inhibit microbial adhesion to UTD materials. This work aimed to evaluate the effect of pre-established Lactobacillus plantarum biofilms on the adhesion of Escherichia coli to medical-grade silicone. The optimal growth conditions of lactobacilli biofilms on silicone were first assessed in 12-well plates. Then, biofilms of L. plantarum were placed in contact with E. coli suspensions for up to 24 h under quasi-static conditions. Biofilm monitoring was performed by determining the number of culturable cells and by confocal laser scanning microscopy (CLSM). Results showed significant reductions of 76%, 77% and 99% in E. coli culturability after exposure to L. plantarum biofilms for 3, 6 and 12 h, respectively, corroborating the CLSM analysis. The interactions between microbial cell surfaces and the silicone surface with and without L. plantarum biofilms were also characterized using contact angle measurements, where E. coli was shown to be thermodynamically less prone to adhere to L. plantarum biofilms than to silicone. Thus, this study suggests the use of probiotic cells as potential antibiofilm agents for urinary tract applications.

15.
Mar Drugs ; 19(7)2021 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-34356809

RESUMO

The growing requirement for sustainable processes has boosted the development of biodegradable plastic-based materials incorporating bioactive compounds obtained from waste, adding value to these products. Chitosan (Ch) is a biopolymer that can be obtained by deacetylation of chitin (found abundantly in waste from the fishery industry) and has valuable properties such as biocompatibility, biodegradability, antimicrobial activity, and easy film-forming ability. This study aimed to produce and characterize poly(lactic acid) (PLA) surfaces coated with ß-chitosan and ß-chitooligosaccharides from a Loligo opalescens pen with different molecular weights for application in the food industry. The PLA films with native and depolymerized Ch were functionalized through plasma oxygen treatment followed by dip-coating, and their physicochemical properties were assessed by Fourier-transform infrared spectroscopy, X-ray diffraction, water contact angle, and scanning electron microscopy. Their antimicrobial properties were assessed against Escherichia coli and Pseudomonas putida, where Ch-based surfaces reduced the number of biofilm viable, viable but nonculturable, and culturable cells by up to 73%, 74%, and 87%, respectively, compared to PLA. Biofilm growth inhibition was confirmed by confocal laser scanning microscopy. Results suggest that Ch films of higher molecular weight had higher antibiofilm activity under the food storage conditions mimicked in this work, contributing simultaneously to the reuse of marine waste.


Assuntos
Antibacterianos/farmacologia , Quitosana/química , Loligo , Animais , Organismos Aquáticos , Biofilmes/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Embalagem de Alimentos , Peso Molecular , Espectroscopia de Infravermelho com Transformada de Fourier
16.
Molecules ; 26(14)2021 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-34299652

RESUMO

Implantable medical devices (IMDs) are susceptible to microbial adhesion and biofilm formation, which lead to several clinical complications, including the occurrence of implant-associated infections. Polylactic acid (PLA) and its composites are currently used for the construction of IMDs. In addition, chitosan (CS) is a natural polymer that has been widely used in the medical field due to its antimicrobial and antibiofilm properties, which can be dependent on molecular weight (Mw). The present study aims to evaluate the performance of CS-based surfaces of different Mw to inhibit bacterial biofilm formation. For this purpose, CS-based surfaces were produced by dip-coating and the presence of CS and its derivatives onto PLA films, as well surface homogeneity were confirmed by contact angle measurements, Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The antimicrobial activity of the functionalized surfaces was evaluated against single- and dual-species biofilms of Staphylococcus aureus and Pseudomonas aeruginosa. Chitosan-based surfaces were able to inhibit the development of single- and dual-species biofilms by reducing the number of total, viable, culturable, and viable but nonculturable cells up to 79%, 90%, 81%, and 96%, respectively, being their activity dependent on chitosan Mw. The effect of CS-based surfaces on the inhibition of biofilm formation was corroborated by biofilm structure analysis using confocal laser scanning microscopy (CLSM), which revealed a decrease in the biovolume and thickness of the biofilm formed on CS-based surfaces compared to PLA. Overall, these results support the potential of low Mw CS for coating polymeric devices such as IMDs where the two bacteria tested are common colonizers and reduce their biofilm formation.


Assuntos
Biofilmes/efeitos dos fármacos , Quitosana , Implantes Experimentais/microbiologia , Pseudomonas aeruginosa/fisiologia , Staphylococcus aureus/fisiologia , Biofilmes/crescimento & desenvolvimento , Quitosana/química , Quitosana/farmacologia , Propriedades de Superfície
17.
Langmuir ; 37(27): 8177-8189, 2021 07 13.
Artigo em Inglês | MEDLINE | ID: mdl-34184901

RESUMO

It is well established that many leaf surfaces display self-cleaning properties. However, an understanding of how the surface properties interact is still not achieved. Consequently, 12 different leaf types were selected for analysis due to their water repellency and self-cleaning properties. The most hydrophobic surfaces demonstrated splitting of the νs CH2 and ν CH2 bands, ordered platelet-like structures, crystalline waxes, high-surface-roughness values, high-total-surface-free energy and apolar components of surface energy, and low polar and Lewis base components of surface energy. The surfaces that exhibited the least roughness and high polar and Lewis base components of surface energy had intracuticular waxes, yet they still demonstrated the self-cleaning action. Principal component analysis demonstrated that the most hydrophobic species shared common surface chemistry traits with low intra-class variability, while the less hydrophobic leaves had highly variable surface-chemistry characteristics. Despite this, we have shown through partial least squares regression that the leaf water contact angle (i.e., hydrophobicity) can be predicted using attenuated total reflectance Fourier transform infrared spectroscopy surface chemistry data with excellent ability. This is the first time that such a statistical analysis has been performed on a complex biological system. This model could be utilized to investigate and predict the water contact angles of a range of biological surfaces. An understanding of the interplay of properties is extremely important to produce optimized biomimetic surfaces.


Assuntos
Folhas de Planta , Ceras , Interações Hidrofóbicas e Hidrofílicas , Análise de Componente Principal , Propriedades de Superfície
18.
Environ Res ; 198: 111219, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33965385

RESUMO

The control of marine biofouling has raised serious environmental concerns, thus the continuous release of toxic and persistent biocidal agents applied as anti-biofouling coatings have triggered the search for non-toxic strategies. However, most of them still lack rigorous evaluation of their ecotoxicity and antifouling effects under real scenarios and their correlation with simulated assays. In this work, the biocide releasing risk and ecotoxicity of a biocidal and foul-release polydimethylsiloxane (PDMS)-based marine coating containing grafted Econea biocide (<0.6 wt.%) were evaluated under simulated real mechanical wear conditions at a pilot-scale system, and under extreme wear scenarios (washability settings). The coating system demonstrated low environmental impact against the model Vibrio fischeri bacterium and marine algae, associated with the effective biocide grafting in the coating matrix and subsequent biocide release minimization. This multifunctional coating system also showed auspicious antifouling (AF) effects, with an AF performance index significantly higher (API > 89) than a single foul-release system (AF < 40) after two and half years at a real immersion scenario in the Portuguese shore of the Atlantic Ocean. These field results corroborated the antibiofilm performance evaluated with Pseudoalteromonas tunicata at simulated dynamic marine conditions after seven-week assays. This eco-friendly multifunctional strategy, validated by both simulated testing conditions and real field tests, is believed to be a powerful tool for the development of AF technologies and a potential contribution to the quest for new environmentally friendly antifouling solutions.


Assuntos
Incrustação Biológica , Desinfetantes , Incrustação Biológica/prevenção & controle , Desinfetantes/toxicidade , Pseudoalteromonas
19.
J Mater Chem B ; 9(17): 3705-3715, 2021 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-33871523

RESUMO

Hospital-acquired infections are still a major concern worldwide, being frequently related to bacterial biofilm formation on medical devices, and thus difficult to eradicate with conventional antimicrobial treatments. Therefore, infection-preventive solutions based on natural polymers are being investigated. Recently, a marine cyanobacterium-derived polymeric coating (CyanoCoating) has demonstrated great anti-adhesive potential when immobilized onto gold model substrates. In this work, we took this technology a step closer to an industrial application by covalently immobilizing CyanoCoating onto medical grade polyurethane (PU). This immobilization was developed through the introduction of linkable moieties onto a PU inert surface using different pre-treatments. Besides the application of the polydopamine (pDA) linker layer, other processes frequently found in industrial settings, such as atmospheric plasma (using O2 or N2 as reactive gases) and ozone surface activations, were evaluated. From all the pre-treatments tested, the ozone activation was the most promising since the obtained coating not only revealed a homogeneous distribution, but also significantly reduced the adhesion of two relevant etiological bacteria in static conditions (the Gram-positive Staphylococcus aureus and the Gram-negative Escherichia coli). Moreover, it also impaired E. coli biofilm formation under simulated urinary tract dynamic conditions, reinforcing the potential of CyanoCoating as an antibiotic-free alternative to mitigate medical device-associated infections, particularly in the urinary tract.


Assuntos
Anti-Infecciosos/química , Materiais Revestidos Biocompatíveis/química , Cianobactérias/química , Indóis/química , Gases em Plasma/química , Polímeros/química , Poliuretanos/química , Anti-Infecciosos/farmacologia , Aderência Bacteriana , Biofilmes , Materiais Revestidos Biocompatíveis/metabolismo , Escherichia coli/efeitos dos fármacos , Cinética , Nitrogênio/química , Ozônio/química , Poliuretanos/metabolismo , Staphylococcus aureus/efeitos dos fármacos , Propriedades de Superfície , Temperatura , Fatores de Tempo
20.
iScience ; 24(1): 102001, 2021 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-33490909

RESUMO

Although high-performance carbon materials are widely used in surface engineering, with emphasis on carbon nanotubes (CNTs), the application of CNT nanocomposites on medical surfaces is poorly documented. In this study, we aimed to evaluate the antimicrobial and anti-adhesive properties of CNT-based surfaces. For this purpose, a PRISMA-oriented systematic review was conducted based on predefined criteria and 59 studies were selected for the qualitative analysis. Results from the analyzed studies suggest that surfaces containing modified CNTs, and specially CNTs conjugated with different polymers, exhibited strong antimicrobial and anti-adhesive activities. These composites seem to preserve the CNT toxicity to microorganisms and promote CNT-cell interactions, as well as to protect them from nonspecific protein adsorption. However, CNTs cannot yet compete with the conventional strategies to fight biofilms as their toxicity profile on the human body has not been thoroughly addressed. This review can be helpful for the development of new engineered medical surfaces.

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