Nano-Assembled Supramolecular Films from Chitosan-Stabilized Gold Nanoparticles and Cobalt(II) Phthalocyanine

Silva, Anna T. B.; Coelho, Andreane G.; Lopes, Lourdes C. da S.; Martins, Marccus V. A.; Crespilho, Frank N.; Merkoçi, Arben; Silva, Welter C. da

doi:10.5935/0103-5053.20130157

Cited by 11 publications

(11 citation statements)

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“…AuNPs-Cit and AgNPs-Cit exhibited SPR bands at 519 and 442 nm, respectively, which are values consistent with those previously reported (Fig. S2) (El-Bashir et al 2013, Silva et al 2013. Furthermore, both TA-coated nanoparticles have broader bands than citrate-coated ones, indicating an increase in the size or aggregation of nanoparticles (Melo et al 2012), later proved by TEM measurements.…”

Section: Resultssupporting

confidence: 90%

“…For TA, two bands were observed at 207 nm (ɛ = 11151.4 L•mol -1 •cm -1 ) and 277 nm (ɛ = 973 L•mol -1 •cm -1 ) attributed to electronic transitions of the aromatic rings conjugated with the carbonyl groups (Shutava et al 2005). Two bands were observed for HAuCl 4(aq) , both attributed to the metal-ligand charge transfer TA-coated gold and silver nanoparticles SPR bands were red-shifted compared to values reported in literature, 520 and 380-450 nm, respectively (Sharifi et al 2015, Silva et al 2013. This bathochromic effect is likely caused by the supramolecular interaction between the nanoparticles and the surface-protecting TA polyphenol, altering the electron transfer energy.…”

Section: Resultsmentioning

confidence: 80%

“…Incorporation of natural products to synthesize hybrid nanomaterials promotes low environmental toxicity and less synthesis-associated biological hazards. Also, this practice contributes to developing stable and biocompatible nanomaterials, enhancing their value for medicine (Medici et al 2015, Agnihotri et al 2013, Silva et al 2013. In this work, TA was used as reducing and capping agent to synthesize silver and gold nanoparticles aiming at a more effective treatment for leishmaniasis.…”

Section: Preparation Of Aunps-ta and Aunps-citmentioning

confidence: 98%

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Silver and gold nanoparticles from tannic acid: synthesis, characterization and evaluation of antileishmanial and cytotoxic activities

Lopes

Brito

Bezerra

et al. 2018

An. Acad. Bras. Ciênc.

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Gold (Au0) and silver (Ag0) nanoparticles were synthesized using tannic acid (TA) as both reducing and stabilizer. Nanoparticles formation, stability, and interaction with TA were compared to citrate-coated nanoparticles and monitored by UV-Vis, zeta potential, and transmission electron microscopy. TA coating resulted in a red-shift and broadening of bands compared to citrate-coated nanoparticles (NPs-Cit). AgNPs-TA and AuNPs-TA are negatively charged with mean surface charge of -29.4 mV and -29.6 mV, respectively. TEM images showed polydispersety of AuNPs-TA (6-42 nm) and aggregation of AgNPs-TA (12-71 nm). In vitro assays of Leishmania amazonensis promastigotes showed an increment of antileishmanial activity for AgNPs-TA in relation to AgNPs-Cit, while AuNPs-TA and AuNPs-Cit did not affect the protozoas at tested concentrations. CC50 value for AgNPs-TA suggested that TA attenuates nanosilver toxicity comparatively to its precursor (Ag+). This investigation can contribute to the development of new, green, and fast produced drugs aiming at leishmaniasis treatment.

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Section: Resultssupporting

confidence: 90%

Section: Resultsmentioning

confidence: 80%

Section: Preparation Of Aunps-ta and Aunps-citmentioning

confidence: 98%

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Silver and gold nanoparticles from tannic acid: synthesis, characterization and evaluation of antileishmanial and cytotoxic activities

Lopes

Brito

Bezerra

et al. 2018

An. Acad. Bras. Ciênc.

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“…Several materials can be utilized in the self-assembly approach, such as fullerenes [4], carbon nanotubes [5], semiconductor oxides [6] and inorganic complexes [7]. The unique properties of the resulting materials allows them to be used in various devices, such as electronic and electrochemical devices and (bio)sensors and catalysts [8,9,10,11], because the proprieties of nanomaterials differ from those of bulk materials.…”

Section: Introductionmentioning

confidence: 99%

New Hybrid Nanomaterial Based on Self-Assembly of Cyclodextrins and Cobalt Prussian Blue Analogue Nanocubes

Carvalho

Silva

Macedo

et al. 2015

IJMS

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Supramolecular self-assembly has been demonstrated to be a useful approach to developing new functional nanomaterials. In this work, we used a cobalt Prussian blue analogue (PBA, Co3[Co(CN)6]2) compound and a β-cyclodextrin (CD) macrocycle to develop a novel host-guest PBA-CD nanomaterial. The preparation of the functional magnetic material involved the self-assembly of CD molecules onto a PBA surface by a co-precipitation method. According to transmission electronic microscopy results, PBA-CD exhibited a polydisperse structure composed of 3D nanocubes with a mean edge length of 85 nm, which became shorter after CD incorporation. The supramolecular arrangement and structural, crystalline and thermal properties of the hybrid material were studied in detail by vibrational and electronic spectroscopies and X-ray diffraction. The cyclic voltammogram of the hybrid material in a 0.1 mol·L−1 NaCl supporting electrolyte exhibited a quasi-reversible redox process, attributed to Co2+/Co3+ conversion, with an E1/2 value of 0.46 V (vs. SCE), with higher reversibility observed for the system in the presence of CD. The standard rate constants for PBA and PBA-CD were determined to be 0.07 and 0.13 s−1, respectively, which suggests that the interaction between the nanocubes and CD at the supramolecular level improves electron transfer. We expect that the properties observed for the hybrid material make it a potential candidate for (bio)sensing designs with a desirable capability for drug delivery.

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“…The possible capping mechanism was also proposed by a different research group. Silva, Coelho, Lopes, Martins, Crespilho, Merkoçi, & da Silva (2013) showed the influence of steric stabilization that depends on pH and high ionic strength. Furthermore, chitosan has been observed to interact with nanoparticles preventing their aggregation (dos Santos et al, 2004).…”

Section: R E S U L T S a N D Discussionmentioning

confidence: 99%

Nanoparticle embedded chitosan film for agglomeration free TEM images

Dogan

Çiftçi

Çetin

et al. 2016

Microsc. Res. Tech.

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Transmission electron microscopy (TEM) is a very useful and commonly used microscopy technique, used especially for the characterization of nanoparticles. However, the identification of the magnetic nanoparticle could be thought problematic in TEM analysis, due to the fact that the magnetic nanoparticles are usually form aggregates on the TEM grid to form bigger particles generating higher stability. This prevents to see exact shape and size of each nanoparticle. In order to overcome this problem, a simple process for the formation of well-dispersed nanoparticles was conducted, by covering chitosan film on the unmodified copper grid, it was said to result in aggregation-free TEM images. It is also important to fix the magnetic nanoparticles on the TEM grids, due to possible contamination of TEM filament which is operated under high vacuum conditions. The chitosan film matrix also helps to protect the TEM filament from contact with magnetic nanoparticles during the imaging process. The proposed procedure offers a quick method to fix the nanoparticles in a conventional copper TEM grid and chitosan matrix prevents agglomeration of nanoparticles, and thus getting TEM images showing well-dispersed individual nanoparticles.

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Nano-Assembled Supramolecular Films from Chitosan-Stabilized Gold Nanoparticles and Cobalt(II) Phthalocyanine

Cited by 11 publications

References 0 publications

Silver and gold nanoparticles from tannic acid: synthesis, characterization and evaluation of antileishmanial and cytotoxic activities

Silver and gold nanoparticles from tannic acid: synthesis, characterization and evaluation of antileishmanial and cytotoxic activities

New Hybrid Nanomaterial Based on Self-Assembly of Cyclodextrins and Cobalt Prussian Blue Analogue Nanocubes

Nanoparticle embedded chitosan film for agglomeration free TEM images

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