Browsing by Author "Ribeiro, Alessandra B."
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- Antimicrobial efficacy of building material based on ZnO/palygorskite against gram-negative and gram-positive bacteriaPublication . Rosendo, Frederico R.G.V.; Pinto, Lucas I.F.; Lima, Idglan S. de; Trigueiro, Pollyana; Honório, Luzia M. de C.; Fonseca, Maria Gardênnia; Osajima, Josy A.; Ribeiro, Alessandra B.This study investigated ZnO nanoparticles immobilized in palygorskite clay mineral (Pal) that acted as an inorganic antimicrobial agent in a commercial mortar aiming to control microorganisms and improve safety and stability for building applications. ZnO/Pal nanocomposites were obtained by sol-gel methods at pH 7 and 11 and were calcined at 250 °C and 400 °C to evaluate different synthesis parameters. The mortar/ZnO/Pal composite was obtained using 5% (by weight) ZnO/Pal hybrid mixed with a commercial mortar. The results show that pH and calcination temperature influenced the properties of ZnO/Pal. ZnO was observed in the ZnO/Pal samples during the wurtzite phase by analyzing the XRD patterns. FTIR spectra illustrated the interactions between ZnO nanoparticles and the fibrous clay mineral. TG-DTG analysis showed the thermal events of Pal before and after zinc incorporation. Scanning electron microscopy (SEM) evaluated ZnO morphology as spherical in shape and dispersed on the fibers of the clay minerals, which presented needle-like morphology. ZnO/Palygorskite showed a possible antibacterial effect when used in mortar formulation. The mortar/ZnO/Pal composites were effective against Escherichia coli and Staphylococcus aureus bacteria when tested by the direct contact method in darkness and in visible light and could be an alternative antimicrobial material for building surfaces.
- Bio-based superabsorbent hydrogels for nutrient releasePublication . Ribeiro, Alessandra B.; Moreira, Helena; Pereira, Sofia I. A.; Godinho, Mariana; Sousa, Ana Sofia da Silva; Castro, Paula; Pereira, Carla F.; Casanova, Francisca; Freixo, Ricardo; Pintado, Manuela E.; Ramos, Óscar L.Drought is characterized by a low water precipitation rate, with strong impact on crop productivity, threatening global food production. In this context, the use of soil amendments, such as superabsorbent hydrogels constitute a potential technology for better water use efficiency and higher crop yields. In this work, we synthesised cellulose-based hydrogels, characterized their physical and functional properties, evaluated their impact on the environment, and their potential to be used as a soil amendments. The hydrogel showed pH of 6.0 to 7.5 and conductivity below 10.0 µS cm-1. The Fourier-transform infrared spectroscopy (FTIR) showed a low intensity peak in the crystallinity region, which was supported by the low crystallinity index (27.3% ± 0.6) verified by Powder X-ray diffraction (PXRD) analysis. The swelling capacity reached more than 200 g of water, the hydrogel showed good resistance to osmotic pressure and high thermostability, which favours the application in hot and arid areas. In addition, no potentially hazardous compound was detected, nor was there any adverse effect on soil microorganisms. Further, the hydrogel was found to be safe for use during seed sowing and for promoting seedling development. In the greenhouse pot experiment, the hydrogels showed a significant increase in maize shoot and root biomass, demonstrating their ability to contribute to the overall water holding capacity of the soil, thereby influencing nutrient availability for more efficient plant growth. In conclusion, the superabsorbent hydrogel exhibited promising characteristics for use as a soil amendment, scalability potential and constitutes a sustainable alternative for agricultural applications.
- Bio-based superabsorbent hydrogels for nutrient-controlled releasePublication . Ribeiro, Alessandra B.; Moreira, Helena; Pereira, Sofia I. A.; Godinho, Mariana; Castro, Paula; Pereira, Carla F.; Casanova, Francisca; Freixo, Ricardo; Pintado, Manuela E.; Ramos, Óscar L.The drought is characterized by a low water precipitation rate, with strong impact on the crop productivity, threaten global food production. In this context, the use of soil amendments, such as superabsorbent hydrogels constitute a potential technology for water use efficiency and increase crop yields. In this work, it was synthesised a cellulose-based hydrogel, carrying out its characterisation, evaluated its environmental safety and its potential to be used as a soil amendment. The hydrogel was successfully synthesised using a simple process and inexpensive reagents. The hydrogel showed pH of 6.0 to 7.5 and conductivity below 10.0 µS cm-1. The FTIR showed a low intensity peak in the crystallinity region, which was supported by the low crystallinity index (27.3 % ± 0.6) verified by PXRD analysis. The swelling capacity reached more than 200 g of water, the hydrogel showed good resistance to osmotic pressure and high thermostability, which favours the application in hot and arid areas. Regarding the safety evaluation, no potentially hazardous compound was detected, nor was there any adverse effect on soil microrganisms. In addition, the hydrogel was found to be safe for use during sowing and for promoting seedling development. In the green pot experiment, the hydrogel demonstrated a significant increase in maize biomass, root biomass and potential to serve as a reservoir for soil nutrients. In conclusion, the superabsorbent hydrogel exhibited promising characteristics for use as a soil amendment, scalability potential and constitutes a sustainable alternative for agricultural applications.
- Biological potential and bioaccessibility of encapsulated curcumin into cetyltrimethylammonium bromide modified cellulose nanocrystalsPublication . Casanova, Francisca; Pereira, Carla F.; Ribeiro, Alessandra B.; Castro, Pedro M.; Freixo, Ricardo; Martins, Eva; Tavares-Valente, Diana; Fernandes, João C.; Pintado, Manuela E.; Ramos, Óscar L.Curcumin is a natural phenolic compound with important biological functions. Despite its demonstrated efficacy in vitro, curcumin biological activities in vivo are dependent on its bioaccessibility and bioavailability, which have been highlighted as a crucial challenge. Cetyltrimethylammonium bromide-modified cellulose nanocrystals (CNC-CTAB) have been shown to be effective in curcumin encapsulation, as they have the potential to enhance biological outcomes. This study evaluated the biological effects of curcumin encapsulated within CNC-CTAB structures, namely its antioxidant, anti-inflammatory and antimicrobial properties, as well as the release profile under digestion conditions and intestinal permeability. Encapsulated curcumin demonstrated antioxidant and anti-inflammatory properties, effectively reducing reactive oxygen species and cytokine production by intestinal cells. The delivery system exhibited antimicrobial properties against Campylobacter jejuni bacteria, further suggesting its potential in mitigating intestinal inflammation. The system showed the ability to protect curcumin from degradation and facilitate its interaction with the intestinal epithelium, highlighting the potential of CNC-CTAB as carrier to enhance curcumin intestinal biological functions.
- Biopolymer from Annona muricata residues as a potential sustainable raw material for industrial applicationsPublication . Ramos, Igor F. S.; Dias, Samuel C.; Lopes, Talissa B. C.; Júnior, Francisco T. dos S. Silva; Araújo, Ricardo de; Gutierrez, Stanley J. C.; Pessoa, Claudia; Osajima, Josy A.; Rizzo, Marcia S.; Silva-Filho, Edson C.; Amorim, Manuela; Ramos, Óscar; Ribeiro, Alessandra B.; Costa, Marcilia P.Annona muricata is a fruit species belonging to the Annonaceae family, which is native to the warmer tropical areas of North and South America. A large amount of discarded residue from A. muricata is of interest for obtaining new industrial inputs. To propose the applications of the biopolymer from A. muricata residues (Biop_AmRs), this study aimed to characterize this input chemically and functionally, as well as to evaluate its potential for hemocompatibility and cytotoxicity activity in vitro. Biop_AmRs is an anionic heteropolysaccharide composed of glucose, arabinose, xylose, galactose, mannose, uronic acid, and proteins. This biopolymer exhibited a semicrystalline structure and good thermal stability. Biop_AmRs exhibited excellent water holding capacity, emulsifying properties, and mucoadhesiviness and demonstrated hemocompatibility and cytocompatibility on the L929 cell line. These results indicate possible applications for this biopolymer as a potential environmentally friendly raw material in the food, pharmaceutical, biomedical, and cosmetic industries.
- Bleached hair as standard template to insight the performance of commercial hair repair productsPublication . Martins, Eva; Castro, Pedro; Ribeiro, Alessandra B.; Pereira, Carla F.; Casanova, Francisca; Vilarinho, Rui; Moreira, Joaquim; Ramos, Óscar L.The increasing demand for effective hair care products has highlighted the necessity for rigorous claims substantiation methods, particularly for products that target specific hair types. This is essential because the effectiveness of a product can vary significantly based on the hair’s condition and characteristics. A well-defined bleaching protocol is crucial for creating a standardized method to assess product efficacy, especially for products designed to repair damaged hair. The objective of this study was to create a practical bleaching protocol that mimics real-world consumer experiences, ensuring that hair samples exhibit sufficient damage for testing. This approach allows for a reliable assessment of how well various products can repair hair. The protocol serves as a framework for evaluating hair properties and the specific effects of each product on hair structure. Color, brightness, lightness, morphology, and topography were primarily used to understand the big differences in the hair fiber when treated with two repair benchmark products, K18® and Olaplex®, in relation to the Bleached hair. The devised bleaching protocol proved to be a fitting framework for assessing the properties of hair and the unique characteristics of each tested product within the hair fiber. This protocol offers valuable insights and tools for substantiating consumer claims, with morphological and mechanical methods serving as indispensable tools for recognizing and validating claims related to hair. The addition of K18® and Olaplex® demonstrated an increase in hair brightness (Y) and lightness (L* and a*) in relation to the Bleached samples, which were considered relevant characteristics for consumers. Olaplex®’s water-based nature creates a visible inner sheet, effectively filling empty spaces and improving the disulfide linkage network. This enhancement was corroborated by the increased number of disulfide bonds and evident changes in the FTIR profile. In contrast, K18®, owing to the lipophilic nature of its constituents, resulted in the formation of an external layer above the fiber. The composition of each of the products had a discrete impact on the fiber distribution, which was an outcome relevant to the determination of spreadability by consumers.
- Carboxymethyl cellulose as a food emulsifier: are its days numbered?Publication . Costa, Eduardo M.; Silva, Sara; Pereira, Carla F.; Ribeiro, Alessandra B.; Casanova, Francisca; Freixo, Ricardo; Pintado, Manuela; Ramos, Óscar L.Carboxymethyl cellulose use in industry is ubiquitous. Though it is recognized as safe by the EFSA and FDA, newer works have raised concerns related to its safety, as in vivo studies showed evidence of gut dysbiosis associated with CMC’s presence. Herein lies the question, is CMC a gut pro-inflammatory compound? As no work addressed this question, we sought to understand whether CMC was pro-inflammatory through the immunomodulation of GI tract epithelial cells. The results showed that while CMC was not cytotoxic up to 25 mg/mL towards Caco-2, HT29-MTX and Hep G2 cells, it had an overall pro-inflammatory behavior. In a Caco-2 monolayer, CMC by itself increased IL-6, IL-8 and TNF-α secretion, with the latter increasing by 1924%, and with these increases being 9.7 times superior to the one obtained for the IL-1β pro-inflammation control. In co-culture models, an increase in secretion in the apical side, particularly for IL-6 (692% increase), was observed, and when RAW 264.7 was added, data showed a more complex scenario as stimulation of pro-inflammatory (IL-6, MCP-1 and TNF-α) and anti-inflammatory (IL-10 and IFN-β) cytokines in the basal side was observed. Considering these results, CMC may exert a pro-inflammatory effect in the intestinal lumen, and despite more studies being required, the incorporation of CMC in foodstuffs must be carefully considered in the future to minimize potential GI tract dysbiosis.
- Cello-oligosaccharides from sugarcane bagasse and their emerging potential as prebiotic agentsPublication . Freixo, Ricardo; Ribeiro, Alessandra B.; Costa, Eduardo M.; Bastos, Francisca; Pereira, Carla F.; Pintado, Manuela E.; Ramos, Óscar L.
- Cellulose from sugarcane bagasse as a potential prebiotic agentPublication . Freixo, Ricardo; Bastos, Francisca; Costa, Eduardo; Ribeiro, Alessandra B.; Pereira, Carla F.; Pintado, Manuela E.; Ramos, Oscar L.
- Cellulose from sugarcane bagasse as a potential prebiotic agentPublication . Freixo, Ricardo; Casanova, Francisca; Costa, Eduardo; Ribeiro, Alessandra B.; Pereira, Carla F.; Pintado, Manuela E.; Ramos, Óscar L.Organic farming practices have been slowly replacing intensive agriculture with the use of plant growth promoting bacteria as key factor, as these bacteria interact effectively with plants and increase crop yields. However, despite the potential of bioinoculants, its usage in agriculture is still limited as their efficacy also depends upon other abiotic factors such as the soil type and its nutrients. A novel approach to bypass this limitation is the introduction of prebiotic agents to increase the richness of the soil and thus promote bacterial growth (Arif et., al 2020). Among the possible alternatives for soil supplementation, cellulose constitutes one of the best choices, as it is a renewable carbon source, widely abundant in nature and for which a great number of microorganisms produce enzymes. The aim of this work is to evaluate the prebiotic potential of cellulose, extracted from sugarcane bagasse, as prebiotic agent. To that end, cellulose was firstly extracted from sugarcane bagasse through an optimized procedure comprising an alkaline extraction with sodium hydroxide followed by a bleaching process with hydrogen peroxide. The capacity to promote the growth (prebiotic effect) of three soil representative microorganisms and nitrogen fixators i.e., Rhodococcus sp. EC35, Pseudomonas azotoformans and Chryseobacterium humi was evaluated for two cellulose extracts (i.e., raw cellulose and cellulose pulp) obtained from sugarcane bagasse. The results showed that the extraction process yielded ca. 63% and 42% for raw cellulose and cellulose pulp, respectively, being both extracts effective as prebiotic agents for the target microorganisms. Growth rates of 38 and 68% for Rhodococcus sp., and of 67 and 84% for C. humi was found for cellulose pulp and raw cellulose, respectively. On the other hand, for P. azotoformans, raw cellulose had no impact upon the growth rate, while cellulose pulp lead to a small decrease (ca. 7%). When comparing this data with the obtained for a standard cellulose from Sigma, it was possible to observe that the commercial cellulose was, in general, less effective as an environmental prebiotic as it only exhibited significant effects in the growth of C. humi. These results showed the potential of sugarcane bagasse as source of a natural bioinocula with prebiotic effect, thus potentiating the valorization of an industrial byproduct with low commercial value into a product with biological effect on soils supplementation.