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Topaz (Al2F1·44(OH)0·56SiO4)/corundum (Al2O3) composites were prepared by a facile and novel reversible process from the sintering of synthetic topaz and AlF3 powders, with corundum formed in situ into the topaz matrix. The corundum formation reaction occurs in the temperature range 875-975 °C, from 40 min sintering time, obtaining the topaz- Al2F1·44(OH)0·56SiO4/corundum- Al2O3 composites. Although sintering temperature and time increment lead to higher corundum formation in the topaz matrix (78.4 wt % Al2O3 at 975 °C for 60 min), longer residence times give place to corundum percentage decrease due to topaz reconversion. The composites' microstructure is characterized by a rectangular bar with stacked pyramidal ends and polycrystals of hexagonal plates for topaz and corundum, respectively. For the topaz/corundum composites, the maximum density was 3.05 g/cm3 (17 % porosity) for specimens sintered at 925 °C for 20 min. The glow curves of the topaz/in situ corundum composite sintered at 975 °C and 0 min dwell time show thermoluminescent peaks between 180 and 250 °C, useful for dosimetric applications. The most helpful peak (at 221 °C) in the topaz/corundum composite's glow curves determined by computational deconvolution is sharp and exhibits the highest thermoluminescent response. Dose-response analysis of the composite (sintered at 975 °C for 0 min) with the best thermoluminescent response revealed two ranges of linear behavior, the first from 2 to 200 mGy, with an adjustment of 99.9 % and the second in the range 5-300 Gy (99.8 % fitting). The thermoluminescent response improvement of the topaz/corundum composites is attributed to the corundum formed in situ during sintering. Fading rate studies of the composite with the best sintering treatment revealed a signal decrease of 4 % after 15 days, which remained constant for up to 30 days, and 8 % after 60 days. The kinetic parameters, kinetics order (b), activation energy (E), and frequency factor (s) determined using the glow peak shape method showed second-order kinetics. The topaz/corundum composite with the best TL response (975 °C, 0 min) presents an effective atomic number (Zeff) of 11.74. The detection of lower doses (mGy) and the linear response at higher doses (Gy) of beta 90Sr, together with the other thermoluminescent properties, suggest that the topaz/corundum composites sintered at 975° for 0 min dwell time may find application in radiotherapy, geological dating, and environmental dosimetry.
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This study has the novel aim of experimentally examining the efficiency of a pilot-scale treatment plant, composed of a multi-tube type falling-film distillation column equipped with a biphasic thermosiphon, for treating a real sample of high-salinity produced water (electrical conductivity of 20,700 µS cm-1). It investigates the influence of operational parameters, including feed temperature and steam chamber temperature of the biphasic thermosiphon, on distillate flow rate and reduction of conductivity. All experimental conditions tested achieved a reduction greater than 98% in terms of electrical conductivity. The production of treated water increased with increasing feed temperature; the flow rate increased from 20.8 L h-1 to 28.2 L h-1 as the feed temperature was increased from 80 °C to 90 °C, when the steam chamber temperature was fixed at 119 °C. Within the temperature range of the steam chamber, the specific energy consumption during the treatment process, with respect to the biphasic thermosiphon, remained practically unchanged between 0.58 kWh L-1 and 0.60 kWh L-1, when the feed temperature was 90 °C. The results proved the potential of the falling-film distillation technology assisted by heat pipes to be a promising proposal for removing salinity from produced water from oil extraction operations.
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Vapor , Água , Humanos , Destilação , Estudos de Viabilidade , Condutividade Elétrica , FebreRESUMO
Aim: The dose response in growth inhibition of Staphylococcus aureus treated with colloidal copper oxide nanoparticles (CuO-NP) was evaluated. Methods: An in vitro microbial viability assay was conducted with CuO-NP concentrations spreading over the 0.4-848.0 µg/ml range. The dose-response curve was modeled with a double Hill equation. UV-Visible absorption and photoluminescence spectroscopies allowed tracking concentration-dependent modifications in CuO-NP. Results: Two specific phases separated by the critical concentration of 26.5 µg/ml were observed in the dose-response curve, with each exhibiting proper IC50 parameters, Hill coefficients and relative amplitudes. Spectroscopy techniques reveal the occurrence of a concentration-triggered aggregation of CuO-NP starting from this critical concentration. Conclusion: The findings demonstrate a dose-related change in S. aureus sensitivity to CuO-NP, which probably arises from the aggregation of this agent.
Antibacterial agents are often used to stop the growth of bacteria such as Staphylococcus aureus (S. aureus). Copper oxide nanoparticles (CuO-NP) stand as a promising candidate for this purpose. Generally, the agent´s effectiveness is inspected following a dose-response curve in which de agent´s antibacterial response is plotted against its dose (concentration). In this work, employing an extended mathematical interpretation we were capable of discerning experimentally the existence of two stages of dose-response (biphasic dose-response) in the treatment of S. aureus with CuO-NP. These results in combination with insights from spectroscopic techniques lead to the understanding that the biphasic behavior arises from the aggregation of CuO-NP at high concentrations. Therefore, according to the adopted concentration to treat S. aureus, the agent can behave as a dispersed nanoparticle or as an aggregated nanoparticle. In summary, understanding whether antibacterial agents transform as a function of concentration is important in determining their practical applications.
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Nanopartículas Metálicas , Nanopartículas , Staphylococcus aureus , Cobre/farmacologia , Nanopartículas Metálicas/química , Nanopartículas/química , Óxidos , Antibacterianos/farmacologia , Antibacterianos/química , Testes de Sensibilidade MicrobianaRESUMO
La anafilaxia es una reacción en su mayoría de hipersensibilidad tipo I, que estimula la activación generalizada de mastocitos, y provoca un cuadro clínico multisistémico que puede ser fatal. Se estima que tiene una incidencia de 0,03-0,1% y una prevalencia de vida de 0,5-2% en la población general. Generalmente, la reacción inmunológica ocurre posterior a la ingesta de alimentos, uso de medicamentos o picaduras de insectos, pero también se han descrito mecanismos no inmunológicos (no IgE) que actúan directamente sobre los mastocitos, llamadas en la literatura "reacciones anafilactoideas". La anafilaxia fue descrita por Paul Portier y Charles Robert Richet en 1902 en perros, los cuales desarrollaban esta reacción posterior a la inyección repetida de veneno de anémonas (medusas). Sin embargo, esta entidad no tuvo criterios diagnósticos ni pilares de manejo estructurado hasta el año 2006. En ese año en se publicó el segundo simposio de manejo de la anafilaxia, en donde se definieron criterios diagnósticos clínicos claros y el rol fundamental de la adrenalina en su manejo; la única droga que cambia el pronóstico del paciente.
Anaphylaxis is mainly a type I hypersensitivity reaction. It triggers a widespread activation of mast cells, causing a multisystemic clinical scenario that can be fatal. It is estimated to have an incidence of 0.03-0.1% and a lifetime prevalence of 0.5-2%. Most immunological reactions occur after food ingestion, medication, or insect stings, but non-immunological (non-IgE) mechanisms that act directly on mast cells, called Anaphylactoid Reactions, have been also described. Anaphylaxis was described by Paul Portier and Charles Robert Richet in 1902 in dogs, that developed this disease after repeated injections of anemones (jellyfish) venom. However, this entity didn't have established diagnostic criteria or an standarized management until 2006. In this year, the second anaphylaxis management sym-posium took place and clear clinical diagnostic criteria were defined. The fundamental role of adrenaline in its management was also established. The former is the only drug that has demonstrated to improve prognosis of the patient
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Dissolution testing is important in assessing the in vitro drug release performance for oral administration dosage forms. However, currently, a simple and efficient in vitro test to investigate critical factors that may impact the drug release and bioavailability at the development stage of a drug-loaded nanoemulsion (NE) is lacking. Thus, in this study, we developed a new combined biphasic and modified cylinder (BP + MC) method to evaluate the dissolution profile of NEs. Flubendazole (FLZ), a Biopharmaceutical Classification System (BCS) Class II drug, offers a new prospective for drug repositioning for treating lung cancer and cryptococcal meningitis. We compared the drug release profiles of three different FLZ formulations (micronized as a suspension, loaded in NE, and solubilized in oil) by using three different methods (dialysis bag, modified cylinder method, and a new BP + MC method). The results showed potential higher drug release of FLZ from the suspension compared to FLZ-loaded NE at pH 1.2, and higher drug release from FLZ-loaded NE compared to other forms in octanol phase. These results correlate well with the in vivo test performed in mice carried out in our previous works. Furthermore, the partition mechanism of the drug released from the NE is discussed in-depth in this article, as well as the advantage of drug-loaded NEs over other preparations in creating supersaturable conditions. Based on the results, we provide new insights into how dissolution methods for a poorly water-solubility drug can be designed. Therefore, we present this new combined BP + MC method as a potential new discriminative dissolution test for future studies when developing drug-loaded NE and comparing with other dosage forms.
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Solubilidade , Camundongos , Animais , Preparações Farmacêuticas , Estudos Prospectivos , Liberação Controlada de Fármacos , Composição de Medicamentos , Administração OralRESUMO
Monte Carlo dynamics were used to simulate the enzymatic starch digestion. Enzyme and starch molecules were distributed on a periodic grid and allowed to stochastically interact according to the kinetics scheme S + E â P + E. Digestion of gelatinized dispersions was simulated by assuming limited mobility of starch and complete mobility of enzymes and products. The results showed that the starch conversion kinetics follows the exponential model X(t) = X∞(1 - exp (-kHt)). On the other hand, the simulation of native granular starch digestion considered non-mobile aggregates of starch molecules hydrolyzed to products by mobile enzyme molecules. The results showed the presence of bi-phasic digestion patterns, which were linked to the transition from a regular to an irregular (fractal-like) granule morphology as a consequence of the erosion of the granule surface by the enzyme action. The simulation results were contrasted qualitatively with experimental results for gelatinized and granular starch digestion.
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Digestão , Amido , Simulação por Computador , Cinética , Método de Monte CarloRESUMO
The search for gold-standard materials for bone regeneration is still a challenge in reconstruction surgery. The ratio between hydroxyapatite (HAp) and ß-tricalcium phosphate (ß-TCP) in biphasic calcium phosphate ceramics (BCPs) is one of the most important factors in osteoinduction promotion and controlled biodegradability, configurating what is currently considered as a possible gold standard material for bone substitution in reconstructive surgery. Exploring the natural genesis of the HAp and ß-TCP phases in fishbones during their postnatal growth, this study developed a biphasic bioceramic obtained from the calcination of Nile tilapia (Oreochromis niloticus) bones as a function of their ages. The natural genesis dynamics of the structural evolution of the ß-TCP and HAp phases were characterized by physicochemical methods, taking into account of the age of the fish and the material processing conditions. Thermal analysis (TGA / DTA) showed complete removal of the organic matter and transitions associated with the transformation of carbonated hydroxyapatite (CDHA) to HAp and ß-TCP phases. After calcination at 900 °C, the material was characterized by: X-ray diffraction (XRD) and refinement by the Rietveld method; Fourier Transform Infrared Spectroscopy with Attenuated Total Reflection (FTIR-ATR); Raman spectroscopy; Scanning Electron Microscopy (SEM) and Flame Atomic Absorption Spectroscopy (FAAS). The analysis allowed identification and quantitative estimate of the variations of the HAp and ß-TCP phases in the formation of the BCPs. The results showed that the decrease in ß-TCP against the increase in the HAp phases is symmetrical to the dynamics of the natural genesis of these phases, surprisingly maintaining the balanced phase proportion even when bones of young fishes were used. The microstructure analysis confirms the observed transformation. In addition, in vivo tests demonstrated the osteoinductive potential of BCP scaffolds implanted in an ectopic site, and their remarkable regenerative functionality, as bone graft, was demonstrated in alveolar bone after tooth extraction. MTT cytotoxicity assay for BCP samples for MC3T3-E1 pre-osteoblasts and L929 fibroblasts cells showed viability equal or higher than 100%. A logistic empirical model is presented to explain the three stages of HAp natural formation with fish age and it is also compared to the fish size evolution.
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Fosfatos de Cálcio , Durapatita , Animais , Regeneração Óssea , Fosfatos de Cálcio/química , Fosfatos de Cálcio/farmacologia , Cerâmica , Durapatita/química , Hidroxiapatitas/químicaRESUMO
Fish bones are a natural calcium phosphate (CaP) sources used in biomaterials production for bone regeneration. CaP scaffolds can be enriched with other substances with biological activity to improve bone repair. This study aimed to evaluate the physicochemical properties and bone regeneration potential of biphasic calcium phosphate (BCP) scaffolds impregnated with free curcumin (BCP-CL) or complexed with ß-cyclodextrin (BCP-CD) compared to BCP scaffolds. Rietveld's refinement showed that BCP is composed of 57.2% of HAp and 42.8% of ß-TCP and the molar ratio of Ca/P corresponds to 1.59. The scaffolds presented porosity (macro and microporosity) of 57.21%. Apatite formation occurred on the BCP, BCP-CL, and BCP-CD surface, in vitro, in SBF. Micro-Raman technique showed a reduction in the dissolution rate of ß-TCP in the curcumin-impregnated scaffolds over time, and in vivo studies on critical-size defects, in rat calvaria, had no additional regenerative effect of BCP-CL and BCP-CD scaffolds, compared to BCP scaffolds. Despite this, the study showed that curcumin impregnation in BCP scaffolds prolongs the release of the ß-TCP phase, the BCP- phase with the higher osteoinductive potential, representing an advantage in tissue engineering.
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Curcumina , beta-Ciclodextrinas , Animais , Regeneração Óssea , Curcumina/farmacologia , Hidroxiapatitas , Ratos , Alicerces Teciduais/química , beta-Ciclodextrinas/farmacologiaRESUMO
ß-fructofuranosidases (FFases) are enzymes involved in sucrose hydrolysis and fructo-oligosaccharides' production which are of great interest for the food industry. FFase from Aspergillus tamarii URM4634 was extracted using PEG/Phosphate Aqueous Biphasic Systems (ABS), and the impact of magnetic field on the extraction behavior was evaluated. A 24-full experimental design was employed to study the influence of molar mass of PEG, concentrations of PEG and phosphate and pH on the selected response variables, i.e., partition coefficient (K), purification factor (PF), activity yield (Y) and selectivity (S). The influence of magnetic field during partition and NaCl concentration on the same responses was also studied. The best results of FFase extraction without magnetic field (K = 0.50, PF = 4.05, Y = 72.66% and S = 0.06) were observed at pH 8.0 using 12.5% (w/w) PEG 400 and 25% (w/w) NaH2PO4/K2HPO4. Application of the magnetic field allowed improving the performance, with the best results being obtained at the longest distance between magnets (lowest magnetic field) and absence of NaCl (K = 0.93, PF = 4.22, Y = 83.79% and S = 0.09). The outcomes obtained demonstrate that ABS combination with low intensity magnetic field can be used as an efficient FFase pre-purification method.
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Fosfatos , beta-Frutofuranosidase , Aspergillus , Campos Magnéticos , Polietilenoglicóis , Cloreto de Sódio , ÁguaRESUMO
For a drug to excerpt pharmacological action after oral intake, it first needs to be released from the formulation, get into solution (dissolve), be absorbed, and reach the systemic circulation. Since only solubilized drugs can be absorbed, and thus have therapeutic effect, the understanding of the dissolution and drug release processes of a drug product is of primary importance. Such understanding allows a robust formulation development with an ideal in vivo performance. In order to meet set standards, the performance assessment of oral drug products, such as dissolution testing, often applies conditions that are not reflective of the in vivo environment. The use of non-physiologically relevant dissolution method during the drug product development phase can be misleading and give poor mechanistic understanding of the in vivo dissolution process. Hence, we hypothesized that applying physiologically relevant conditions to the dissolution test would result in more accurate in vivo predictability for a robust and precise development process. Since the buffering system in the intestinal lumen operates at low molarity values, phosphate buffer at low buffer capacity was used as a first approach to an in vivo relevant parameter. Furthermore, a biphasic system was used, that is, the low buffer capacity medium was paired with an organic layer (n-octanol) to mimic the concurrent drug absorption that happens with the in vivo dissolution. Both poorly and highly soluble drugs in immediate release formulations (ibuprofen and metronidazole, respectively) were tested in this set-up to assess the dissolution in the aqueous medium and the partitioning to the organic phase. Additionally, enteric coated formulations were tested in bicarbonate buffer at the in vivo reported molarities values to assess the impact of buffer species on drug dissolution. The evaluated parameters were the buffer system (bicarbonate buffer vs. phosphate buffer), buffer capacity and medium pH. In all approaches, dissolution was also carried out in compendial buffer for comparison purposes. Our results demonstrate that the USP-recommended dissolution method greatly lacked discriminatory power, whereas low buffer capacity media discriminated between manufacturing methods. The use of an absorptive phase in the biphasic dissolution test assisted in controlling the medium pH due to the drug removal from the aqueous medium. Hence, the applied noncompendial methods were more discriminative to drug formulation differences and manufacturing methods than conventional dissolution conditions. In this study, it was demonstrated how biphasic dissolution and a low buffer capacity can be used to assess drug product performance differences. This can be a valuable approach during the early stages of drug product development for investigating drug release with improved physiological relevance. Similarly, all the enteric coated formulations displayed a fast release in phosphate buffer and complied with the compendial performance specifications. On the other hand, they all had a much slower drug release in bicarbonate buffer and failed the USP acceptance criteria. Also, the nature of the drug (acid vs base) impacted the dissolution behavior in bicarbonate buffer. This study indicates that compendial dissolution test for enteric coated tablets lacks physiological relevance and it needs to be reevaluated. Thus, an in vivo relevant performance method for EC products is needed. Overall, the findings of this thesis comprehensively demonstrates that meaningful differences in performance and accordance to clinical reports were only obtained when physiological relevant conditions were applied. Hence, our results indicate that the central hypothesis was answered positively
Para que um medicamento exerça a ação farmacológica após a ingestão oral, ele primeiro precisa ser liberado da formulação, dissolver, ser absorvido e atingir a circulação sistêmica. Uma vez que apenas medicamentos solubilizados podem ser absorvidos e, assim, ter efeito terapêutico, a compreensão dos processos de dissolução e liberação de um medicamento é de extrema importância. Tal compreensão permite o desenvolvimento de uma formulação robusta com o desempenho in vivo ideal. Para atender aos padrões regulatórios previamente estabelecidos, a avaliação da performance de formulações orais, como por exemplo, o teste de dissolução, frequentemente aplica condições que não refletem o ambiente fisiológico. O uso de métodos de dissolução não fisiologicamente relevante durante a fase de desenvolvimento do medicamento pode gerar resultados equivocados sem uma compreensão mecanistica do processo de dissolução in vivo. Portanto, a hipótese desse trabalho é que a aplicação de condições fisiologicamente relevantes no teste de dissolução resultaria em uma predição mais precisa da dissolução in vivo para um processo de desenvolvimento robusto e preciso. Uma vez que o sistema tampão no lúmen intestinal possui baixa molaridade, o tampão fosfato com baixa capacidade tamponante foi usado como uma primeira abordagem como um meio de dissolução fisiologicamente relevante. Além disso, foi utilizado um sistema bifásico, ou seja, o meio de baixa capacidade tamponante combinado a uma fase orgânica (n-octanol) para imitar a absorção in vivo. Formulações de liberação imediata contendo fármacos de baixa e de alta solubilidade (ibuprofeno e metronidazol, respectivamente) foram testadas no sistema bifásico para avaliar a dissolução no meio aquoso e a partição para a fase orgânica. Ademais, formulações com revestimento entérico foram testadas em tampão bicarbonato nos valores de molaridades fisiológicos para avaliar o impacto da espécie tamponante na dissolução do fármaco. Os parâmetros avaliados foram o sistema tampão (tampão bicarbonato vs. tampão fosfato), capacidade tamponante e pH médio. Em todas as abordagens, a dissolução também foi realizada em tampão farmacopeico para fins de comparação. Nossos resultados demonstraram que o método de dissolução farmacopeico não foi discriminativo, enquanto o meio com menor capacidade tamponante diferenciou entre as formulações obtidas via granulação úmida ou compressão direta. Ademais, a utilização da fase orgânica no teste de dissolução bifásica auxiliou no controle do pH do meio aquoso. Portanto, os métodos não compendiais aplicados foram mais discriminativos do que as condições de dissolução convencionais. Neste estudo, foi demonstrado como a dissolução bifásica e uma baixa capacidade tamponante podem ser usadas para avaliar as diferenças na performance de formulações. Esta pode ser uma abordagem valiosa durante os estágios iniciais do desenvolvimento de medicamentos para investigar a liberação destes sob condições fisiologicamente relevantes. Da mesma forma, todas as formulações com revestimento entérico exibiram uma liberação rápida em tampão de fosfato e atenderam às especificações farmacopeicas. Entretanto, a liberação do fármaco foi muito mais lenta em tampão de bicarbonato e consequentemente não cumpriram com as especificações farmacopeicas. Além disso, a natureza do fármaco (ácido vs. base) impactou o comportamento de dissolução no tampão de bicarbonato. Este estudo indica que o teste de dissolução convencional para comprimidos de liberação retardada não possui relevância fisiológica e precisa ser reavaliado. Portanto, os resultados desta tese demonstram de forma abrangente que diferenças significativas na performance condizentes com relatórios clínicos foram obtidas apenas quando as condições fisiológicas relevantes foram aplicadas. Esses resultados indicam que a hipótese central foi respondida positivamente
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Preparações Farmacêuticas/análise , Ações Farmacológicas , Otimização de Processos , Dissolução , Desenvolvimento de Medicamentos/instrumentação , Química Farmacêutica/instrumentação , Composição de Medicamentos , Eficiência , Liberação Controlada de Fármacos , Necessidades e Demandas de Serviços de Saúde/classificação , Concentração de Íons de Hidrogênio , Metronidazol/efeitos adversosRESUMO
Abstract Nanoscale biomaterials are commonly used in a wide range of biomedical applications such as bone graft substitutes, gene delivery systems, and biologically active agents. On the other hand, the cytotoxic potential of these particles hasn't yet been studied comprehensively to understand whether or not they exert any negative impact on the cellular structures. Here, we undertook the synthesis of beta-tricalcium phosphate (ß-TCP) and biphasic tricalcium phosphate (BCP) nanoparticles (NPs) and determine their concentration-dependent toxic effects in human fetal osteoblastic (hFOB 1.19) cell line. Firstly, BCP and β-TCP were synthesized using a water-based precipitation technique and characterized by X-Ray Diffraction (XRD), Raman Spectroscopy, and Transmission Electron Microscopy (TEM). The cytological effects of β-TCP and BCP at different concentrations (0-640 ppm) were evaluated by using 3- (4,5-dimethylthiazol-2-yl) -2,5-diphenyltetrazolium bromide (MTT) and lactate dehydrogenase (LDH) assays. The total oxidative status (TOS) parameter was used for investigating oxidative stress potentials of the NPs. In addition, the study assessed the DNA damage product 8-hydroxy-2′-deoxyguanosine (8-Oxo-dG) level in hFOB 1.19 cell cultures. The results indicated that the β-TCP (above 320 ppm) and BCP (above 80 ppm) NPs exhibited cytotoxicity effects on high concentrations. It was also observed that the oxidative stress increased relatively as the concentrations of NPs increased, aligning with the cytotoxicity results. However, the NPs concentrations of 160 ppm and above increased the level of 8-OH-dG. Consequently, there is a need for more systematic in vivo and in vitro approaches to the toxic effects of both nanoparticles.
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BACKGROUND PEGylation, defined as the covalent attachment of polyethylene glycol, allows the synthesis of PEGylated therapeutic proteins with enhanced physicochemical properties. Traditional alkylating Nterminal PEGylation reactions on amine groups involve the use of modified linear mono-methoxy polyethylene glycol (mPEG) molecules looking for the synthesis of mono-PEGylated products. However, this approach requires different purification steps since inevitably undesired cross-linked products are synthesized. Herein, we propose the use of reactive aqueous two-phase systems (ATPS) to produce and purify PEGylated therapeutic conjugates using Ribonuclease A (RNase A) as a model protein. RESULTS: Selected linear 5 kDa and 20 kDa mPEG potassium phosphate systems were produced according to equilibrium data obtained from constructed binodal curves. All reactive systems were able to generate biphasic systems and to PEGylate RNase A. Two 5 kDa and two 20 kDa systems were selected based on the reaction yield percentage and the feasibility of purifying the mono-PEGylated RNase A from the diPEGylated and native RNase A by contrasting the differences in their partition behaviors. The remnant biological activity was of 94% and of 100% for the mono-PEGylated RNase A purified from the 5 kDa and 20 kDa mPEG systems when compared to the mono-PEGylated conjugate obtained by standard procurement methods.
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Polietilenoglicóis/química , Proteínas/isolamento & purificação , Proteínas/químicaRESUMO
Joint cartilage damage affects 10-12% of the world's population. Medical treatments improve the short-term quality of life of affected individuals but lack a long-term effect due to injury progression into fibrocartilage. The use of mesenchymal stem cells (MSCs) is one of the most promising strategies for tissue regeneration due to their ability to be isolated, expanded and differentiated into metabolically active chondrocytes to achieve long-term restoration. For this purpose, human adipose-derived MSCs (Ad-MSCs) were isolated from lipectomy and grown in xeno-free conditions. To establish the best differentiation potential towards a stable chondrocyte phenotype, isolated Ad-MSCs were sequentially exposed to five differentiation schemes of growth factors in previously designed three-dimensional biphasic scaffolds with incorporation of a decellularized cartilage matrix as a bioactive ingredient, silk fibroin and bone matrix, to generate a system capable of being loaded with pre-differentiated Ad-MSCs, to be used as a clinical implant in cartilage lesions for tissue regeneration. Chondrogenic and osteogenic markers were analyzed by reverse transcription-quantitative PCR and cartilage matrix generation by histology techniques at different time points over 40 days. All groups had an increased expression of chondrogenic markers; however, the use of fibroblast growth factor 2 (10 ng/ml) followed by a combination of insulin-like growth factor 1 (100 ng/ml)/TGFß1 (10 ng/ml) and a final step of exposure to TGFß1 alone (10 ng/ml) resulted in the most optimal chondrogenic signature towards chondrocyte differentiation and the lowest levels of osteogenic expression, while maintaining stable collagen matrix deposition until day 33. This encourages their possible use in osteochondral lesions, with appropriate properties for use in clinical patients.
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Aqueous biphasic systems (ABSs) are an interesting alternative for separating industrial enzymes due to easy scale-up and low operational cost. The proteases of Pseudomonas sp. M211 were purified through ABS platforms formed by polyethylene glycol (PEG) and citrate buffer salt. Two experimental designs 23 + 4 were performed to evaluate the following parameters: molar mass of PEG (MPEG ), concentration of PEG (CPEG ), concentration of citrate buffer (CCit ), and pH. The partition coefficient (K), activity yield (Y), and purification factor (PF) were the responses analyzed. The best purification performance was obtained with the system composed of MPEG = 10,000 g/mol, CPEG = 22 wt%, CCit = 12 wt%, pH = 8.0; the responses obtained were K = 4.9, Y = 84.5%, PF = 15.1, and tie-line length = 52.74%. The purified proteases of Pseudomonas sp. (PPP) were used to obtain hydrolysates of Lupinus mutabilis (Peruvian lupin cultivar) seed protein in comparison with the commercial protease Alcalase® 2.4L. A strong correlation between hydrolysis degree and radical scavenging activity was observed, and the highest antioxidant activity was obtained with Alcalase® (1.40 and 3.47 µmol Trolox equivalent/mg protein, for 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) and oxygen radical absorbance capacity, respectively) compared with PPP (0.55 and 1.03 µmol Trolox/mg protein). Nevertheless, the IC50 values were lower than those often observed for antioxidant hydrolysates from plant proteins. PEG/citrate buffer system is valuable to purify Pseudomonas proteases from the fermented broth, and the purified protease could be promising to produce antioxidant protein hydrolysates.
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Proteínas de Bactérias , Fracionamento Químico/métodos , Peptídeo Hidrolases , Hidrolisados de Proteína , Pseudomonas/enzimologia , Antioxidantes/química , Antioxidantes/isolamento & purificação , Antioxidantes/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/isolamento & purificação , Proteínas de Bactérias/metabolismo , Lupinus/química , Peptídeo Hidrolases/química , Peptídeo Hidrolases/isolamento & purificação , Peptídeo Hidrolases/metabolismo , Peptídeos/química , Peptídeos/isolamento & purificação , Peptídeos/metabolismo , Proteínas de Plantas/análise , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Polietilenoglicóis/química , Hidrolisados de Proteína/análise , Hidrolisados de Proteína/química , Hidrolisados de Proteína/metabolismoRESUMO
This review will discuss, under the Circular Economy and Biorefinery concepts, the performance of the alternative solvents in the downstream process to recover natural pigments in a more sustainable way. Conventionally, pigments marketed on an industrial scale are produced through chemical synthesis by using petroleum derivatives as the main raw material. Also, the current production chain of the synthetic dyes is linear, with no solvent recycling and waste generation. Thus, the most promising processes of extraction and purification of natural pigments and strategies on the polishing of the solvents are here reviewed. In this review, the use of alternative solvents, namely, ionic liquids, eutectic solvents, aqueous solutions of surfactants, and edible oils, for recovering natural pigments was reviewed. Works discussing higher extraction yields and selectivity, while maintaining the stability of the target pigments, were reported. Also, a panorama between Sustainability and Circular Economy prospection was discussed for better comprehension of the main advances in the field. Behind the analysis of the works published so far on the theme, the most important lacunas to overcome in the next years on the field were pointed out and discussed. Also, the future trends and new perspectives to achieve the economic viability and sustainability of the processes using alternative solvents will be scrutinized.
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Líquidos Iônicos , Fenômenos Químicos , Corantes , Alimentos , SolventesRESUMO
The use of the biphasic isotropic/nematic region in a bisperylene imide-based lyotropic liquid crystal system allows the extraction of proton-carbon 1 DCH residual dipolar couplings in aqueous solution from a single F1-coupled HSQC experiment. The method was successfully applied to the RDC-based conformational analysis of sucrose.
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Conditional differentiation between haploids and diploids has been proposed to drive the evolutionary stability of isomorphic biphasic life cycles. The cost of producing and maintaining genetic information has been posed as a possible driver of this conditional differentiation. Under this hypothesis, haploids benefit over diploids in resource-limited environments by halving the costs of producing and maintaining DNA. Spared resources can be allocated to enhance survival, growth or fertility. Here we test in the field whether indeed haploids have higher growth rates than diploids. Individuals of the red seaweed Agarophyton chilense, were mapped and followed during 2 years with 4-month census intervals across different stands within the Valdivia River estuary, Chile. As hypothesized, haploids grew larger and faster than diploids, but this was sex-dependent. Haploid (gametophyte) females grew twice as large and 15% faster than diploids (tetrasporophytes), whereas haploid males only grew as large and as fast as the maximum obtained by diploids in summer. However, haploid males maintained their maximum sizes and growth rates constant year-round, while diploids were smaller and had lower growth rates during the winter. In conclusion, our results confirm the conditional differentiation in size and growth between haploids and diploids but also identified important differences between males and females. Besides understanding life cycle evolution, the dynamics of A. chilense frond growth reported informs algal farmers regarding production optimization and should help in determining best planting and harvesting strategies.
Assuntos
Rodófitas , Alga Marinha , Animais , Chile , Diploide , HaploidiaRESUMO
We described a method to produce an injectable bone substitute consisting of a solid and liquid phase, this solid was formed using the coacervation method consisting of a mixture of Hydroxyapatite (HAp) and beta-Tricalcium Phosphate (ß-TCP) which the sodium alginate - precursor - was removed during sinterization. The biphasic calcium phosphate microspheres had varying size distributions depending on the flow rate and these microspheres were mixed with a polymeric solution, chitosan and polyethylene glycol, and depending on the ratio of these phases, the injectability results varied. Nonetheless, the force required for complete removal will not disrupt the accuracy of injection into the bone defect while the biomaterial exhibited no cytotoxicity with promising results from in vivo using tibia bone defect in rabbits at 30 and 60 days whereas bone repair was more intense and accentuated with the usage of the biomaterial, and was gradually absorbed during the evaluated periods.
RESUMO
F1-protein fraction (F1) is a natural bioactive compound extracted from the rubber tree, Hevea brasiliensis, and has been recently studied for its therapeutic potential in wound healing. In this study, we investigated the concentration-dependent effects of F1 (0.01%, 0.025%, 0.05%, and 0.1%) incorporated into deproteinized bovine bone (DBB) and porous biphasic calcium phosphate (pBCP), on the repair of rat calvarial critical-size bone defects (CSBD). The defects were analyzed by 3D-microtomography and 2D-histomorphometry at 12 weeks postsurgery. The binding efficiency of F1 to pBCP (96.3 ± 1.4%) was higher than that to DBB (67.7 ± 3.3%). In vivo analysis showed a higher bone volume (BV) gain in all defects treated with DBB (except in 0.1% of F1) and pBCP (except in 0.05% and 0.1% of F1) compared to the CSBD without treatment/control group (9.96 ± 2.8 mm3 ). DBB plus 0.025% F1 promoted the highest BV gain (29.7 ± 2.2 mm3 , p < .0001) compared to DBB without F1 and DBB plus 0.01% and 0.1% of F1. In the pBCP group, incorporation of F1 did not promote bone gain when compared to pBCP without F1 (15.9 ± 4.2 mm3 , p > .05). Additionally, a small BV occurred in defects treated with pBCP plus 0.1% F1 (10.4 ± 1.4 mm3, p < .05). In conclusion, F1 showed a higher bone formation potential in combination with DBB than with pBCP, in a concentration-dependent manner. Incorporation of 0.25% F1 into DBB showed the best results with respect to bone formation/repair in CSBD. These results suggest that DBB plus 0.25% F1 can be used as a promising bioactive material for application in bone tissue engineering.
Assuntos
Osso e Ossos/química , Osso e Ossos/efeitos dos fármacos , Fosfatos de Cálcio/farmacologia , Látex/farmacologia , Osteogênese/efeitos dos fármacos , Animais , Regeneração Óssea/efeitos dos fármacos , Substitutos Ósseos , Osso e Ossos/diagnóstico por imagem , Osso e Ossos/patologia , Bovinos , Cerâmica , Relação Dose-Resposta a Droga , Látex/química , Masculino , Microcirculação/efeitos dos fármacos , Porosidade , Ratos , Ratos Wistar , Engenharia Tecidual , Microtomografia por Raio-XRESUMO
Efficient analytical methods are required for optimizing dosage of veterinary antibiotics and hormones in order to reduce toxicity and antimicrobial resistance in the environment. Thus, the objective of this work was to develop a rapid and low-cost method for determination of hormone estradiol and antibiotic chlortetracycline in bovine and porcine blood serum by aqueous two-phase system (ATPS) extraction and capillary electrophoresis quantification. ATPS based on ionic liquid cholinium alaninate and citrate salt along with mixtures of protic and aprotic polar solvents were evaluated in terms of recovery of extraction (%R). The liquid-liquid equilibrium, phase diagrams, and tie lines are discussed. Antibiotic migrated to solvent-rich phase (R ≈ 89.0%) to all systems. Estradiol migrates to ionic liquid-rich phase; however, addition of 10% methanol changed partition to solvent-rich phase (R ≈ 89.7%). The method has high recovery and cleanliness, is cost-efficient, scalable, and hence is adequate for screening of antibiotics and hormones tested in animal blood serum for dosage optimization and to predict their environment.