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1.
Environ Res ; 252(Pt 3): 119068, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38705452

RESUMO

Cellulose acetate membranes exhibit a potential to be applied in hemodialysis. However, their performance is limited by membrane fouling and a lack of antibacterial properties. In this research, copper oxide (I) nanoparticles were fabricated in situ into a cellulose acetate matrix in the presence of polyvinylpyrrolidone (pore-forming agent) and sulfobetaine (stabilising agent) to reduce the leakage of copper ions from nano-enhanced membranes. The influence of nanoparticles on the membrane structure and their antibacterial and antifouling properties were investigated. The results showed that incorporating Cu2O NPs imparted significant antibacterial properties against Staphylococcus aureus and fouling resistance under physiological conditions. The Cu2O NPs-modified membrane could pave the way for potential dialysis applications.


Assuntos
Antibacterianos , Incrustação Biológica , Celulose , Cobre , Membranas Artificiais , Staphylococcus aureus , Celulose/análogos & derivados , Celulose/química , Celulose/farmacologia , Cobre/química , Antibacterianos/farmacologia , Antibacterianos/química , Staphylococcus aureus/efeitos dos fármacos , Incrustação Biológica/prevenção & controle , Nanopartículas/química , Nanopartículas Metálicas/química , Povidona/química , Povidona/análogos & derivados
2.
Molecules ; 27(19)2022 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-36235090

RESUMO

According to the American Cancer Society, roughly 54,000 new cases of oral cavity or oropharyngeal cancers have been detected in the United States of America in 2021, and they will cause about 10,850 deaths. The main therapies for cancer management, such as surgery and radio- and chemotherapy, have some own benefits, albeit they are often destructive for surrounding tissues; thus, deep investigations into non-surgical treatments for oral cavities are needed. Biologically active compounds (BACs) extracted from European Spruce needles were analyzed to determine the total phenolic and flavonoid content and were used as additional ingredients for oral hygiene products. An anti-proliferation investigation was carried out using extracts containing BACs with the use of several cell lines (cancer and a normal one). ESI-MS studies on BACs showed that luteolin, a natural flavonoid compound with anti-tumorigenic properties against various types of tumors, is the predominant component of the extracts. MTT, BrdU, and LIVE/DEAD studies demonstrated that BAC extracts obtained from Christmas tree needles possess anticancer properties against squamous cell carcinoma (with epithelial origins). We proved that BAC extracts contain high amounts of luteolin, which induces cytotoxicity toward cancer cells; along with their high selectivity, robustness, and nontoxicity, they are very promising materials in oral health applications.


Assuntos
Luteolina , Árvores , Antioxidantes/farmacologia , Bromodesoxiuridina , Flavonoides/farmacologia , Extratos Vegetais/farmacologia
3.
J Relig Health ; 61(2): 1366-1375, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-34331657

RESUMO

Communication with patients regarding oncology-related aspects is a challenging experience and requires a high level of skill from the interlocutors. The aim of this study was to verify the influence of religion/spirituality in oncological settings from the health professionals' perspectives in Poland. It assessed the role of religion/spirituality in patient-clinician communication, death or stress self-management, empathy, and breaking bad news skills. Data collection was carried out through a standardized self-administered questionnaire with varying scales. The study cohort consisted of 60 medical practitioners specializing in oncological radiotherapy treatments. It was observed that strategies used for coping with patients' death, stress reduction, empathy, communication with patients and/or their relatives, or breaking bad news skills, may be gender-specific or may depend on the length of time employed, as well as experience in a cancer-related work environment. This study shows that spirituality and religiousness can support clinicians in managing challenging or negative emotions related to their work in cancer settings. Religiousness and spirituality can also serve as a potential therapeutic strategies for those exposed to patient suffering and death.


Assuntos
Terapias Espirituais , Espiritualidade , Comunicação , Humanos , Polônia , Religião
4.
Molecules ; 25(7)2020 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-32244513

RESUMO

The current rapid advancement of numerous nanotechnology tools is being employed in treatment of many terminal diseases such as cancer. Nanocapsules (NCs) containing an anti-cancer drug offer a very promising alternative to conventional treatments, mostly due to their targeted delivery and precise action, and thereby they can be used in distinct applications: as biosensors or in medical imaging, allowing for cancer detection as well as agents/carriers in targeted drug delivery. The possibility of using different systems-inorganic nanoparticles, dendrimers, proteins, polymeric micelles, liposomes, carbon nanotubes (CNTs), quantum dots (QDs), biopolymeric nanoparticles and their combinations-offers multiple benefits to early cancer detection as well as controlled drug delivery to specific locations. This review focused on the key and recent progress in the encapsulation of anticancer drugs that include methods of preparation, drug loading and drug release mechanism on the presented nanosystems. Furthermore, the future directions in applications of various nanoparticles are highlighted.


Assuntos
Antineoplásicos/química , Antineoplásicos/farmacologia , Composição de Medicamentos , Nanomedicina Teranóstica , Animais , Biopolímeros/química , Portadores de Fármacos/química , Sistemas de Liberação de Medicamentos , Humanos , Nanocápsulas/química , Nanocápsulas/ultraestrutura , Nanopartículas/química , Nanopartículas/ultraestrutura
5.
Molecules ; 25(15)2020 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-32717865

RESUMO

The development of anticancer therapies that involve natural drugs has undergone exponential growth in recent years. Among the natural compounds that produce beneficial effects on human health, polyphenols have shown potential therapeutic applications in cancer due to their protective functions in plants, their use as food additives, and their excellent antioxidant properties. The possibility of combining conventional drugs-which are usually more aggressive than natural compounds-with polyphenols offers very valuable advantages such as the building of more efficient anticancer therapies with less side effects on human health. This review shows a wide range of trials in which polyphenolic compounds play a crucial role as anticancer medicines alone or in combination with other drugs at different stages of cancer: cancer initiation, promotion, and growth or progression. Moreover, the future directions in applications of various polyphenols in cancer therapy are emphasized.


Assuntos
Antineoplásicos/uso terapêutico , Flavonoides/uso terapêutico , Neoplasias/tratamento farmacológico , Polifenóis/uso terapêutico , Sinergismo Farmacológico , Tratamento Farmacológico , Humanos , Compostos Fitoquímicos/uso terapêutico
6.
J Relig Health ; 59(6): 2671-2677, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33044598

RESUMO

The COVID-19 pandemic has impacted religion and faith in different ways. Numerous restrictions have been implemented worldwide. Believers are in conflict with authorities' warnings that gatherings must be limited to combat the spread of the virus. Religion has always played a role of the balm for the soul, and the regular religious participation is associated with better emotional health outcomes. In our study, we examined whether the exposure to COVID-19 enhances the faith. The instrument used was a survey verifying the power of spirituality in the face of the coronavirus pandemic.


Assuntos
Betacoronavirus , Infecções por Coronavirus/psicologia , Pneumonia Viral/psicologia , Religião , Espiritualidade , COVID-19 , Infecções por Coronavirus/epidemiologia , Feminino , Humanos , Masculino , Pandemias/prevenção & controle , Pneumonia Viral/epidemiologia , Religião e Medicina , SARS-CoV-2
7.
J Hazard Mater ; 465: 133000, 2024 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-38029585

RESUMO

Plastics make our lives easier in many ways; however, if they are not appropriately disposed of or recycled, they may end up in the environment where they stay for centuries and degrade into smaller and smaller pieces, called microplastics. Each year, approximately 42000 tonnes of microplastics end up in the environment when products containing them are used. According to the European Chemicals Agency (ECHA) one of the significant sources of microplastics are microcapsules formulated in home care and consumer care products. As part of the EU's plastics strategy, ECHA has proposed new regulations to ban intentionally added microplastics starting from 2022. It means that the current cross-linked microcapsules widely applied in consumer goods must be transformed into biodegradable shell capsules. The aim of this review is to provide the readers with a comprehensive and in-depth understanding of recent developments in the art of microencapsulation. Thus, considering the chemical structure of the capsule shell's materials, we discuss whether microcapsules should also be categorized as microplastic and therefore, feared and avoided or whether they should be used despite the persisting concern.

8.
Biomed Pharmacother ; 175: 116654, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38692066

RESUMO

This paper explores the therapeutic perspectives of polyphenols and chitosan as potential anticancer agents in the mouthwash formulations. Taking into account the high incidence of squamous cell carcinoma (SCC) among oral cancers, this discussion will concentrate on the potential advantages of these compounds in oral care, focusing on their impact on improving oral health and cancer prevention. According to the data, it appears that the mixture of BACs extract and chitosan may increase the efficiency of the apoptosis of cancer cells while reducing the undesired side effects. The cytotoxicity assays demonstrate a significant reduction in squamous carcinoma cell viability after incubation with BACs extract, with a marked decrease observed over 24-72 hours up to 76%. The anti-cancer properties of the BAC extract are related to luteolin, which is a predominant compound. The addition of 0.025% chitosan reduced the metabolic activity of cancer cells by 37.5%, suggesting a synergistic interaction between the compounds. This research highlights the potential of BACs and chitosan in modulating important molecular targets associated with cancer cell.


Assuntos
Quitosana , Neoplasias Bucais , Antissépticos Bucais , Saúde Bucal , Polifenóis , Quitosana/química , Quitosana/farmacologia , Humanos , Polifenóis/farmacologia , Antissépticos Bucais/farmacologia , Neoplasias Bucais/tratamento farmacológico , Neoplasias Bucais/prevenção & controle , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Apoptose/efeitos dos fármacos , Carcinoma de Células Escamosas/tratamento farmacológico , Carcinoma de Células Escamosas/prevenção & controle , Carcinoma de Células Escamosas/patologia , Composição de Medicamentos
9.
Langmuir ; 29(5): 1601-8, 2013 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-23245267

RESUMO

Photosensitive microcapsules and membranes based on poly(α-methylstilbenesebacoate-co-α-methylstilbeneisophthalate), containing the photosensitive α-methylstilbene moiety, were prepared by a phase-inversion precipitation process. In order to simulate the morphology and behavior of the microcapsule shell under UV irradiation, an exhaustive characterization of a membrane was first performed by ESEM, POM, AFM, and contact angle measurements. The prepared microcapsules contained either chloroform or a concentrated solution of vanillin in chloroform as the core; in all cases, before UV irradiation, their outer surface appeared smooth and dense. The influence of vanillin on microcapsule cross-section morphology was observed by ESEM microscopy. Release of vanillin in water, at room temperature, was markedly influenced by UV irradiation: in the absence of irradiation, it was practically negligible, while when microcapsules were submitted to continuous irradiation with UV light, the surface morphology of the capsules changed drastically and vanillin started to be released after ca. 20 min of irradiation.


Assuntos
Cápsulas/química , Cristais Líquidos/química , Poliésteres/química , Raios Ultravioleta , Cápsulas/síntese química , Estrutura Molecular , Tamanho da Partícula , Poliésteres/síntese química , Propriedades de Superfície
10.
Artigo em Inglês | MEDLINE | ID: mdl-36901614

RESUMO

The rapid advances in science and technology in the field of artificial neural networks have led to noticeable interest in the application of this technology in medicine. Given the need to develop medical sensors that monitor vital signs to meet both people's needs in real life and in clinical research, the use of computer-based techniques should be considered. This paper describes the latest progress in heart rate sensors empowered by machine learning methods. The paper is based on a review of the literature and patents from recent years, and is reported according to the PRISMA 2020 statement. The most important challenges and prospects in this field are presented. Key applications of machine learning are discussed in medical sensors used for medical diagnostics in the area of data collection, processing, and interpretation of results. Although current solutions are not yet able to operate independently, especially in the diagnostic context, it is likely that medical sensors will be further developed using advanced artificial intelligence methods.


Assuntos
Inteligência Artificial , Medicina , Humanos , Aprendizado de Máquina , Redes Neurais de Computação
11.
Environ Sci Pollut Res Int ; 30(39): 90168-90179, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-36517612

RESUMO

The study reported in this article has shown for the first time that strongly acidic solutions (pH < 0.5) obtained after hydrometallurgical treatment of spent automotive converters (SAC) may be valuable secondary sources of platinum group metal (PGM) nanoparticles (NPs). The PGM precipitation strongly depended on the solution pH; the yield of the precipitated PGM NPs increased considerably from 40% to almost 100% when the pH was adjusted to 7-8. To improve the NPs stability, commercial TiO2 was used as support to obtain efficient recyclable PGM@TiO2 catalysts. The size of the PGM NPs was smaller than 5 nm, while the diameter of the supported particles varied from 10 to 50 nm. The size and dispersion of PGM NPs on the support strongly depended on the pH of the medium: at pH < 0.5, the Pt and Pd NPs were significantly smaller than the NPs obtained at pH 7-8. Also, in the case of Pt@TiO2 and Rh@TiO2, the NPs were well dispersed on the support in contrast to the large agglomerates of Pd@TiO2. The PGM@TiO2 showed catalytic properties in the reduction of 4-nitrophenol to 4-aminophenol, particularly, at pH above 11. The highest conversion of 98% was obtained with 1% Pd@TiO2 at pH 14 after only 15 min. The catalyst was easily separated from the reaction mixture and reused in 7 consecutive cycles without significant loss of activity. The PGM@TiO2 synthesized from the real solution showed a similar catalytic activity (70% conversion at pH 14) as that obtained from model solution.


Assuntos
Nanopartículas , Platina , Platina/química , Titânio/química , Nanopartículas/química , Catálise
12.
Int J Biol Macromol ; 233: 123530, 2023 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-36736972

RESUMO

The encapsulation of bluing agents in biodegradable polymeric capsules is an emerging option in laundry detergents sector to substitute formaldehyde-based polymers, because they are non-biodegradable, carcinogenic and toxic. In this work, we present for the first time the successful encapsulation of a blue dye in biodegradable capsules which shell was formed by an alginate hydrogel and a polyethylene glycol network. Different types of capsules were synthesized (addition or not of the diacrylate monomer) and irradiation of the crosslinking solution at different times. Furthermore, a deep characterization of each type of capsules was performed (chemical and morphological characterization, assessment of their mechanical and thermal properties, evaluation of their biodegradability), noting that the incorporation of the diacrylate monomer (PEGDMA) and the two different irradiation times selected substantially affected the final properties of the capsules. The obtained results will serve to comprehend how the dye can be released from the capsules.


Assuntos
Alginatos , Hidrogéis , Hidrogéis/química , Alginatos/química , Cápsulas/química , Polímeros , Ácido Glucurônico/química
13.
Curr Pharm Des ; 29(43): 3421-3427, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38083888

RESUMO

Polyphenols and flavonoids, naturally occurring compounds found abundantly in plants, have gained considerable attention in recent years due to their potential health benefits. Research exploring their bioactive properties has revealed promising therapeutic applications in various diseases. This article aims to provide a comprehensive overview of the intricate journey from academic laboratory discoveries to the availability of polyphenols and flavonoids as drugs on pharmacy shelves. It was shown that the transformation of these natural compounds into effective therapies is a promising avenue for enhancing human health. Yet, fully realizing this potential necessitates sustained scientific exploration, cross-disciplinary collaboration, and continued investment in research and development. This article underscores the importance of sustained collaboration and investment as key pillars of progress towards innovative and effective therapies.


Assuntos
Flavonoides , Farmácia , Humanos , Flavonoides/farmacologia , Flavonoides/uso terapêutico , Polifenóis/farmacologia
14.
Int J Biol Macromol ; 246: 125659, 2023 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-37406917

RESUMO

Beads based on a mannuronate(M)-rich alginate (86 % M units) were prepared by adding the polysaccharide solution to a crosslinking bath containing different concentrations (0.5, 2 and 10 wt%) of XCl2 where X = Ca, Cu or Zn. Primarily focus was on Zn, due to its antioxidant, anti-inflammatory and anti-microbial capabilities. The beads were characterized by Field-Emission Scanning Electron Microscopy (FESEM), Fourier-Transform Infra-Red spectroscopy (FT-IR), Thermogravimetric Analysis (TGA), Small-Angle X-ray Scattering (SAXS) and compression tests. The crosslinking agent significantly influenced the properties of the resulting beads. Specifically, Ca-based beads exhibited a smoother surface, while Cu- and Zn-based beads appeared rougher. Interestingly, Zn-based beads displayed a core-shell structure. Young moduli ranged from 3500 and 7000 MPa, with the highest values observed for Zn-beads. SAXS investigation at 0.5 wt% XCl2 suggested increase in the densely packed domains amount in the order: Ca < Cu < Zn. Extended X-ray Absorption Fine Structure (EXAFS) showed that the coordination number was 4.3 ± 0.4 for Cu, and 4.0 ± 0.2 and 1.1 ± 0.1 for Zn in 0.5 wt% XCl2 alginate xerogels, in agreement with reported Density Functional Calculations on Cu2+- and Zn2+-MM complexes. The results from FT-IR, compositional analysis and EXAFS collectively suggested a bridging coordination for these systems.


Assuntos
Cálcio , Cobre , Cálcio/química , Cobre/química , Zinco/química , Alginatos/química , Espectroscopia de Infravermelho com Transformada de Fourier , Espalhamento a Baixo Ângulo , Difração de Raios X , Géis
15.
Int J Biol Macromol ; 170: 424-436, 2021 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-33383080

RESUMO

Cancer is a major health issue concerning to all of us. Current treatment options are still limited due to not-selective action. Encapsulation is contemplated as an innovative approach to address systemic toxicity and tumor resistance caused by traditional therapies, while increasing encapsulated compounds bioavailability. The coating material of capsules strongly determines the success of the system. Since alginate has been proved non-toxic, biocompatible and biodegradable, it is considered a potential vehicle for therapeutic factors encapsulation. Besides, it has the particular ability to form hydrogels, which hold a high-water content and greatly resemble to natural soft tissues. The present review exposes the state-of-the-art and the most sophisticated alginate-based systems for cancer therapy and research. It begins with an overview of alginate hydrogels and the qualities that make them especially suitable for biomedical applications. In the following section, the application of alginate hydrogels as pioneering strategies for cancer treatment is described. Several examples of alginate-based delivery systems of therapeutic drugs, proteins and nucleic acids are provided. Significant emphasis is placed in both oral delivery systems and colorectal cancer therapy. Moreover, the role of alginate 3-D scaffolds for both cell culture and delivery is explained. Lastly, other applications of alginate-based hydrogels such as tumor biomarkers immunosensing and fluorescent surgical marker are included.


Assuntos
Alginatos/química , Hidrogéis/química , Hidrogéis/farmacologia , Neoplasias/tratamento farmacológico , Animais , Materiais Biocompatíveis/química , Cápsulas/química , Cápsulas/farmacologia , Sistemas de Liberação de Medicamentos/métodos , Humanos , Engenharia Tecidual/métodos
16.
Biochim Biophys Acta Rev Cancer ; 1876(1): 188560, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-33965512

RESUMO

According to World Health Organization (WHO) cancer is the second most important cause of death globally. Because angiogenesis is considered as an essential process of growth, proliferation and tumor progression, within this review we decided to shade light on recent development of chemical compounds which play a significant role in its imaging and monitoring. Indeed, the review gives insight about the current achievements of active agents structures involved in imaging techniques such as: positron emission computed tomography (PET), magnetic resonance imaging (MRI) and single photon emission computed tomography (SPECT), as well as combination PET/MRI and PET/CT. The review aims to provide the journal audience with a comprehensive and in-deep understanding of chemistry policy in tumor angiogenesis imaging.


Assuntos
Meios de Contraste , Imageamento por Ressonância Magnética , Neoplasias/irrigação sanguínea , Neoplasias/diagnóstico por imagem , Neovascularização Patológica , Tomografia por Emissão de Pósitrons , Compostos Radiofarmacêuticos , Inibidores da Angiogênese/uso terapêutico , Animais , Humanos , Neoplasias/tratamento farmacológico , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Valor Preditivo dos Testes , Tomografia Computadorizada de Emissão de Fóton Único
17.
Bioact Mater ; 6(8): 2412-2438, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33553825

RESUMO

Tissue engineering (TE) is a rapidly growing interdisciplinary field, which aims to restore or improve lost tissue function. Despite that TE was introduced more than 20 years ago, innovative and more sophisticated trends and technologies point to new challenges and development. Current challenges involve the demand for multifunctional bioscaffolds which can stimulate tissue regrowth by biochemical curves, biomimetic patterns, active agents and proper cell types. For those purposes especially promising are carefully chosen primary cells or stem cells due to its high proliferative and differentiation potential. This review summarized a variety of recently reported advanced bioscaffolds which present new functions by combining polymers, nanomaterials, bioactive agents and cells depending on its desired application. In particular necessity of study biomaterial-cell interactions with in vitro cell culture models, and studies using animals with in vivo systems were discuss to permit the analysis of full material biocompatibility. Although these bioscaffolds have shown a significant therapeutic effect in nervous, cardiovascular and muscle, tissue engineering, there are still many remaining unsolved challenges for scaffolds improvement.

18.
Materials (Basel) ; 14(3)2021 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-33513724

RESUMO

Our investigation was focused on the preparation and characterization of novel plasters based on Carboxymethyl Chitosan derivative (CMC), to be used for the treatment of radiation dermatitis with Biologic Active Compounds (BACs) in a moist wound-healing environment. After performing the extraction and characterization of BACs from Cistus L., we optimized the BACs/CMC solution for subsequent plaster preparation. Then, plasters were prepared by dip-coating with a different number of layers, and we characterized them by Environmental Scanning Electron Microscopy (ESEM), Contact Angle (CA) and release tests in water for 24 h. Taking into account the flexibility of the plasters and the amount of released BACs after 24 h, the sample obtained after two dip-coating steps (2La) appeared promising in regard to comfortable mechanical properties and active principles administration. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) test performed on keratinocytes cultured in standard medium shows that cells treated with released extract from 2La start to proliferate, extend cellular viability and form colonies typical for epidermal cells.

19.
Langmuir ; 26(18): 14821-9, 2010 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-20799708

RESUMO

Novel composite asymmetrical membranes based on poly(vinyl alcohol)-co-ethylene (EVAL) as the host material and new polyethers that contain azobenzene moieties in the side chain were prepared by dry-cast phase inversion after dissolving the azo polymers in tetrahydrofuran and EVAL in dimethylsulfoxide and subsequently mixing the resulting solutions. By taking advantage of the proper temperature variation in the oven used for solvent evaporation, asymmetrical membranes that exhibited a dense, crystalline layer on the bottom and a porous, mainly amorphous layer on the top were obtained. Remarkable changes in the surface morphology and the contact angle with water were observed on the top surfaces of the composite membranes. This was ascribed not only to the enhanced concentration of azo polymer on the top surface but mostly to a conformational change in EVAL induced by the photoisomerization of the guest azo groups, as shown by HRMAS (1)H NMR. The morphological and structural changes in EVAL could be reversed on exposing the membrane to visible light for 24 h.


Assuntos
Compostos Azo/química , Luz , Membranas Artificiais , Processos Fotoquímicos , Polivinil/química , Molhabilidade/efeitos da radiação , Microscopia de Força Atômica , Microscopia Eletrônica de Varredura , Temperatura de Transição , Raios Ultravioleta , Difração de Raios X
20.
Materials (Basel) ; 13(23)2020 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-33260479

RESUMO

In colloidal methods, the morphology of nanoparticles (size and shape) as well as their stability can be controlled by changing the concentration of the substrate, stabilizer, adding inorganic salts, changing the reducer/substrate molar ratio, and changing the pH and reaction time. The synthesis of silver nanoparticles was carried out according to the modified Lee and Meisel method in a wide pH range (from 2.0 to 11.0) using citric acid and malic acid, without adding any additives or stabilizers. Keeping the same reaction conditions as the concentration of acid and silver ions, temperature, and heating time, it was possible to determine the relationship between the reaction pH, the type of acid, and the size of the silver nanoparticles formed. Obtained colloids were analyzed by UV-Vis spectroscopy and investigated by means of Transmission Electron Microscope (TEM). The study showed that the colloids reduced with citric acid and malic acid are stable over time for a minimum of seven weeks. We observed that reactions occurred for citric acid from pH 6.0 to 11.0 and for malic acid from pH 7.0 to 11.0. The average size of the quasi-spherical nanoparticles changed with pH due to the increase of reaction rate.

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