Green microfluidic synthesis of monodisperse silver nanoparticles via genetic algorithm optimization

Fernandes, Daniel L. A.; Paun, Cristina; Pavliuk, Mariia V.; Fernandes, Arthur B.; Bastos, E. L.; Sá, Jacinto

doi:10.1039/c6ra20877k

Cited by 36 publications

(23 citation statements)

References 35 publications

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“…Betanin (betanidin 5- O -glucoside) is a phenolic betalain found in beetroots ( Beta vulgaris L.) that has been used as an U.S. Food and Drug Administration-approved food colorant additive [16]. The chemical versatility of betanin has led to its application as a redox mediator in dye-sensitized solar cells [17] and hydrogen production systems [18,19], for the synthesis of metal nanoparticles [20], as an anti-inflammatory agent [21], and as an antioxidant [22]. The antioxidant capacity of betanin is comparable to that of ECG due to the presence of a 5- O -glucosyl catechol moiety and a 1,7-diazaheptamethinium [23] system [24,25,26].…”

Section: Introductionmentioning

confidence: 99%

Rationale on the High Radical Scavenging Capacity of Betalains

Nakashima

Bastos

2019

Antioxidants

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Betalains are water-soluble natural pigments of increasing importance as antioxidants for pharmaceutical use. Although non-phenolic betalains have lower capacity to scavenge radicals compared to their phenolic analogues, both classes perform well as antioxidants and anti-inflammatory agents in vivo. Here we show that meta-hydroxyphenyl betalain (m-OH-pBeet) and phenylbetalain (pBeet) show higher radical scavenging capacity compared to their N-methyl iminium analogues, in which proton-coupled electron transfer (PCET) from the imine nitrogen atom is precluded. The 1,7-diazaheptamethinium system was found to be essential for the high radical scavenging capacity of betalains and concerted PCET is the most thermodynamically favorable pathway for their one-electron oxidation. The results provide useful insights for the design of nature-derived redox mediators based on the betalain scaffold.

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Section: Introductionmentioning

confidence: 99%

Rationale on the High Radical Scavenging Capacity of Betalains

Nakashima

Bastos

2019

Antioxidants

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“…Silver NPs stabilized with betanin and derivatives (Bts-Ag NPs) were synthesized in an automated microfluidic reactor using pure betanin extracted from beetroots 24 , as reducing and capping agent. A genetic optimization algorithm was used to ensure that particles size and light absorption are homogeneous 25 . Herein, we used monodispersed spherical Bts-Ag NPs with 28–30 nm, exhibiting a LSP resonance absorption maximum wavelength (λ max ) at 405 nm; refer to the supporting information (SI) for DLS analysis (Fig.…”

Section: Resultsmentioning

confidence: 99%

“…All reagents were purchased from commercial vendors (Sigma Aldrich) and used as received. Ag NPs (nanoparticles) decorated with betalamic acid were synthesized via base hydrolysis of betanin extracted from beetroot in an automated microfluidic reactor with an optimization algorithm that ensures the particles size and light absorption is homogeneous 25 . AgNO 3 was used a metal precursor and betanin works as reducting and capping agent.…”

Section: Methodsmentioning

confidence: 99%

Nano-hybrid plasmonic photocatalyst for hydrogen production at 20% efficiency

Pavliuk

Fernandes

Abdellah

et al. 2017

Sci Rep

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The efficient conversion of light energy into chemical energy is key for sustainable human development. Several photocatalytic systems based on photovoltaic electrolysis have been used to produce hydrogen via water reduction. However, in such devices, light harvesting and proton reduction are carried separately, showing quantum efficiency of about 10–12%. Here, we report a nano-hybrid photocatalytic assembly that enables concomitant reductive hydrogen production and pollutant oxidation with solar-to-fuel efficiencies up to 20%. The modular architecture of this plasmonic material allows the fine-tuning of its photocatalytic properties by simple manipulation of a reduced number of basic components.

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“…The ability of betanin as a metal ion ligand has been further explored in the development of colorimetric sensors for calcium dipicolinate in bacterial spores . Additionally, betanin has been used as a starting material for the synthesis of two‐photon absorbing fluorescent probes and fabrication of nanoparticles .…”

Section: Introductionmentioning

confidence: 99%

Revisiting the Mechanism of Hydrolysis of Betanin

Esteves

Pinheiro

Pioli

et al. 2018

Photochem & Photobiology

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Betanin (betanidin 5-O-β-D-glucoside) is a water-soluble plant pigment used as a color additive in food, drugs and cosmetic products. Despite its sensitivity to light and heat, betanin maintains appreciable tinctorial strength in low acidic and neutral conditions, where the color of other plant pigments, such as anthocyanins, quickly fades. However, betanin is an iminium natural product that experiences acid- and base-catalyzed hydrolysis to form the fairly stable betalamic acid and cyclo-DOPA-5-O-β-D-glucoside. Here, we show that the decomposition of betanin in aqueous phosphate solution pH 2-11 is subject to general base catalysis by hydrogen phosphate ion and intramolecular general acid and base catalysis, providing new insights on the mechanism of betanin hydrolysis. UV/Vis absorption spectrophotometry, H NMR spectroscopy and mass spectrometry were used to investigate product formation. Furthermore, theoretical calculations support the hypothesis that the nitrogen atom of the tetrahydropyridine ring of betanin is doubly protonated, as observed for structurally simpler amino dicarboxylic acids. Our results contribute to the study of betanin and other pigments belonging to the class of betalains and to deepen the knowledge on the chemical properties of imino acids as well as on iminium-catalyzed modifications of carbonyl compounds in water.

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Green microfluidic synthesis of monodisperse silver nanoparticles via genetic algorithm optimization

Abstract: A scalable and green procedure for the microfluidic flow synthesis of monodisperse silver nanoparticles is reported.

Cited by 36 publications

References 35 publications

Rationale on the High Radical Scavenging Capacity of Betalains

Rationale on the High Radical Scavenging Capacity of Betalains

Nano-hybrid plasmonic photocatalyst for hydrogen production at 20% efficiency

Revisiting the Mechanism of Hydrolysis of Betanin

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