ABSTRACT The urine bag is a thermo-labile medical-hospital device used in clinical/surgical procedures in urine drainage and collection. As it is a thermolabile material, it is commonly sterilized by ethylene oxide, a highly toxic, mutagenic and carcinogenic cyclic ether gas. Currently, several countries require, through documents and standards, the quantification of ethylene oxide in medical and hospital devices. Thus, this work describes the development and validation of a method employed for the quantification of ethylene oxide (ETO) in urine bags. The method was developed based on the guidelines of ISO 10993-7, ANVISA and INMETRO. The work range, linearity, limits of detection and quantification, repeatability, intermediate precision and selectivity were evaluated. Statistical tools such as Levene's test, Grubbs, residual analysis, F-test of two variances, paired sample T test and ANOVA table, were also applied to evaluate the method. The linearity of the work range (10 – 400 mg.L-1) showed an adequate correlation coefficient (r > 0.9993), with a homoscedastic profile with absence of outliers while the limit of detection and quantification were 1,95 and 6,5 mg.L-1 respectively. After validation, 45 samples of urine bags of different batches were evaluated, which demonstrated levels of ETO below the limit of detection (1,95 mg.L-1). The results highlight a simple method that meets several regulations with a wide working range, high sensitivity and capability to quantify ETO not only in urine bags but also in other medical devices.

RESUMO Nanomateriais vem atraindo bastante atenção nos últimos anos em virtude das suas propriedades que permitem aplicações em diversas áreas como: química, física, medicina, fármacos e engenharias. No universo dos nanomaterias, as nanopartículas de prata (AgNPs) tem despertado o interesse de vários pesquisadores devido ao seu potencial bactericida. Estudos recentes correlacionaram a eficácia da atividade antimicrobiana com a razão superfície-volume, morfologia, polidispersividade, tamanho de partícula e estabilidade das AgNPs. Este trabalho teve como objetivo compreender a influência do borohidreto de sódio (NaBH4) e do peróxido de hidrogênio (H2O2) nas propriedades das AgNPs. A síntese das AgNPs foi realizada através da redução química de íons de prata com NaBH4, na presença de H2O2 e Citrato de Sódio (SCT). Para determinar a influência causada pelo H2O2 e NaBH4, foram empregados diferentes variações de concentrações e volumes e ao resultado foi aplicado o Teste de Fisher para determinar a significância entre essas variáveis. As amostras foram caracterizadas por Espalhamento Dinâmico de Luz (DLS) e Potencial Zeta. Como resultado, o Teste de Fisher em conjunto com os valores obtidos de tamanho de partícula, estabilidade e polidispersividade determinaram variáveis estatisticamente iguais, ou seja, as variáveis que não influenciam estatisticamente na formação das partículas, bem como, a influência causada pela variação do H2O2 e do NaBH4 nas propriedades das AgNPs. Por fim, a variação da concentração de NaBH4 e volume de H2O2 causam efeitos sob o diâmetro, estabilidade e polidispersividade de AgNPs os quais foram estudados e aqui estão descritos.

ABSTRACT Nanomaterials has attracted a lot of attention in recent years due to its properties that allow applications in several areas such as chemistry, physics, medicine, pharmaceuticals, and engineering. In the nanomaterial universe, silver nanoparticles (AgNPs) have awakened the interest of several researchers because of their bactericidal potential. Recent studies have correlated the efficacy of antimicrobial activity with the surfacevolume ratio, morphology, polydispersity, particle size and AgNPs stability. This work aimed to understand the influence of sodium borohydride (NaBH4) and hydrogen peroxide (H2O2) on the AgNPs properties. The synthesis of AgNPs was performed by chemical reduction of silver ions with sodium borohydride in the presence of hydrogen peroxide and sodium citrate. To determine the influence caused by H2O2 and NaBH4, different concentrations and volume variations were used and a Fisher’s exact test was applied to determine the significance between variables. The samples were characterized by Dynamic Light Scattering (DLS) and Zeta Potential. Results determined that the Fisher’s exact test along with the obtained results of variables of particle size, stability and polydispersity are statistically the same, that is, the variables do not influence statistically the formation of the particles, as well as the influence caused by H2O2 and NaBH4 variation on the AgNPs properties. In summary, variation of NaBH4 concentration and H2O2 volume causes effects under the diameter, stability and polydispersity of AgNPs which have been studied and described herein.

Abstract The aim of this study was to evaluate the degree of conversion (DC) and the thermal stability of bulk-fill and conventional composite resins. Eleven composite resin samples were prepared to evaluate the DC, Vickers microhardness (VMH), mass and residue/particle loss, glass transition temperature (Tg), enthalpy, and linear coefficient of thermal expansion (CTE) using infrared spectroscopy (FTIR), microdurometer analyses, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dilatometry (DIL). The data were subjected to statistical analysis, with a significance level of 95%. DC and VMH were not influenced by the polymerized side of the sample, and statistical differences were recorded only among the materials. Decomposition temperature, melting, and mass and residue loss were dependent on the material and on the evaluation condition (polymerized and non-polymerized). Tg values were similar between the composites, without statistically significant difference, and CTE ranged from 10.5 to 37.1 (10-6/°C), with no statistical difference between the materials. There was a moderate negative correlation between CTE and the % of load particles, by weight. Most resins had a DC above that which is reported in the literature. TGA, Tg, and CTE analyses showed the thermal behavior of the evaluated composites, providing data for future research, assisting with the choice of material for direct or semidirect restorations, and helping choose the appropriate temperature for increasing the DC of such materials.

Abstract Poly(ether ether ketone) (PEEK) has excellent properties, such as high biocompatibility and an elastic modulus similar to bone, which makes it a suitable biomaterial. When modified with sulfuric acid (H2SO4) and hydroxyapatite (HA), its workability and bioactivity is enhanced, and this makes it of great importance in medicine. This study investigates a better combination of process parameters to manufacture sulfonated PEEK/HA (SPEEK/HA) membranes for biomaterials. Chemical, thermal, and biological analyses were carried out on all samples. The sulfonated structure was observed to enhance wettability, adhesion, and cell viability. Furthermore, an increase in the degree of sulfonation facilitated their workability as required for biomaterials; making them suitable for osseointegration. Besides, the SPEEK/HA membranes presented cell adhesion, confirming the viability to use as biomaterial. This study presents a cheap alternative method to easily process biomaterials of improved workability.