Preparation and Characterization of Gold Nanoparticles in Chitosan Suspension by One-Pot Chemical Reduction Method

Narayanan, Radha; Sivakumar, M.

doi:10.4028/www.scientific.net/nh.6.47

Cited by 10 publications

(5 citation statements)

References 9 publications

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“…Thanks to the high DD and thus the high number of amino groups responsible for NPs formation, a high reduction rate for the gold ions is also obtained. 71 Because the reduction and seed formation occur in many places at once, the smallest nanoparticles are formed compared to the other Mw chitosans tested. As the viscosity of the polymer increases, the formation of less nucleation centers is more probable due to the hindered ion diffusion and reducing agent across the gel.…”

Section: Resultsmentioning

confidence: 99%

“…The obtained gold nanoparticles have the smallest size and the most uniform distribution across the resulting films when using this medium Mw chitosan. Thanks to the high DD and thus the high number of amino groups responsible for NPs formation, a high reduction rate for the gold ions is also obtained . Because the reduction and seed formation occur in many places at once, the smallest nanoparticles are formed compared to the other Mw chitosans tested.…”

Section: Resultsmentioning

confidence: 99%

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Development of Noncytotoxic Chitosan–Gold Nanocomposites as Efficient Antibacterial Materials

Regiel-Futyra

Kus‐Liśkiewicz

Sebastián

et al. 2015

ACS Appl. Mater. Interfaces

275

141

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This work describes the synthesis and characterization of noncytotoxic nanocomposites either colloidal or as films exhibiting high antibacterial activity. The biocompatible and biodegradable polymer chitosan was used as reducing and stabilizing agent for the synthesis of gold nanoparticles embedded in it. Herein, for the first time, three different chitosan grades varying in the average molecular weight and deacetylation degree (DD) were used with an optimized gold precursor concentration. Several factors were analyzed in order to obtain antimicrobial but not cytotoxic nanocomposite materials. Films based on chitosan with medium molecular weight and the highest DD exhibited the highest antibacterial activity against biofilm forming strains of Staphylococcus aureus and Pseudomonas aeruginosa. The resulting nanocomposites did not show any cytotoxicity against mammalian somatic and tumoral cells. They produced a disruptive effect on the bacteria wall while their internalization was hindered on the eukaryotic cells. This selectivity and safety make them potentially applicable as antimicrobial coatings in the biomedical field.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Development of Noncytotoxic Chitosan–Gold Nanocomposites as Efficient Antibacterial Materials

Regiel-Futyra

Kus‐Liśkiewicz

Sebastián

et al. 2015

ACS Appl. Mater. Interfaces

275

141

View full text Add to dashboard Cite

show abstract

“…Chit-AuNPs were synthesized utilizing a chemical reduction process, with chitosan acting as both a reducing and stabilizing agent. 38 Volumes of 15 mL of 0.15, 0.25, and 0.35% (w/v) LMW chitosan solutions [in 1% (v/v) aqueous acetic acid] were heated to a temperature of 45 °C and stirred for 3 h. Afterward, the temperature was raised to 75 °C, and 0.15 mL of an aqueous HAuCl 4 solution (100 mM) was added to each of the solutions while under stirring. After 2 h of vigorous stirring under heating, the solutions were moved away from the heating plate and remained under stirring until room temperature ( T R ).…”

Section: Experimental Sectionmentioning

confidence: 99%

Naked-Eye Detection of LAMP-Produced Nucleic Acids in Saliva Using Chitosan-Capped AuNPs in a Single-Tube Assay

Grammatikos,

Svoliantopoulos,

Gizeli

2023

Anal. Chem.

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Loop-mediated isothermal amplification (LAMP) is a low-technology molecular assay that is highly adaptable to point-of-care (POC) applications. However, achieving sensitive naked-eye detection of the amplified target in a crude sample is challenging. Herein, we report a simple yet highly efficient and sensitive methodology for the colorimetric visualization of a single target copy in saliva using chitosan-capped gold nanoparticles (Chit-AuNPs) synthesized via a green chemistry approach. The presence or absence of free Chit in the Chit-AuNPs solution was shown to affect LAMP colorimetric detection oppositely: the observed stabilization in the negative samples and aggregation in the positive samples in the presence of free Chit were reversed in the case of neat Chit-AuNPs. The mechanism of the two assays was investigated and attributed to electrostatic and depletion effects exerted between the Chit-AuNPs, free Chit, and the solution components. The developed contamination-free, one-tube assay successfully amplified and detected down to 1–5 cfu of Salmonella and 10 copies of SARS-CoV-2 per reaction (25 μL) used, respectively, as model DNA and RNA targets in the presence of 20% saliva, making the method suitable for POC applications. Compared to the commonly used pH-sensitive dyes, Chit-AuNPs are shown to have an enhanced sensitivity toward naked-eye colorimetric observation owing to the direct detection of DNA amplicons. Thus, this is a simple, highly sensitive, fast, and versatile naked-eye detection methodology that could be coupled to any LAMP or RT-LAMP assay, avoiding the need of using complicated sample pretreatments and/or AuNPs long and laborious functionalization processes.

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“…Upon protonation of their amine groups in the presence of acetic acid, chitosan chains electrostatically adsorb negatively charged Au (III) ions that are reduced to neutral Au atoms, and further agglomerate to form AuNPs capped with chitosan. 37 A schematic representation of the reaction is shown in Fig. 1a.…”

Section: Synthesis and Characterization Of Chit-aunpsmentioning

confidence: 99%

Naked-Eye Detection of LAMP-Produced Nucleic Acids in Saliva using Chitosan-capped AuNPs in a Single-Tube Assay

Grammatikos,

Svoliantopoulos,

Gizeli

2023

Preprint

View full text Add to dashboard Cite

Loop-mediated isothermal amplification (LAMP) is a low-technology molecular assay highly adaptable to point-of-care (POC) applications. However, achieving sensitive naked-eye detection of the amplified target in a crude sample is challenging. Herein, we report a simple, yet highly efficient and sensitive methodology for the colorimetric visualization of a single target copy in saliva, using chitosan-capped gold nanoparticles (Chit-AuNPs) synthesized via a green-chemistry approach. The presence or absence of free Chit in the Chit-AuNPs solution was shown to affect LAMP colorimetric detection oppositely: the observed stabilization in the negative samples and aggregation in the positive samples in the presence of free Chit was reversed in the case of neat Chit-AuNPs. The mechanism of the two assays was investigated and attributed to electrostatic and depletion effects exerted between the Chit-AuNPs, free Chit and the solution components. The developed contamination-free, one-tube assay successfully amplified and detected down to 1-5 cfu of Salmonella and 10 copies of SARS-CoV-2 per reaction (25 uL) in the presence of 20% saliva, making the method suitable for POC applications. Compared to the commonly used pH sensitive dyes, Chit-AuNPs are shown to have an enhanced sensitivity toward the naked-eye colorimetric observation owing to the direct detection of DNA amplicons. Thus, this is a simple, highly sensitive, fast and versatile naked-eye detection methodology that could be coupled to any LAMP or RT-LAMP assay, avoiding the need of using complicated sample pretreatments and/or AuNPs long and laborious functionalization processes.

show abstract

Preparation and Characterization of Gold Nanoparticles in Chitosan Suspension by One-Pot Chemical Reduction Method

Cited by 10 publications

References 9 publications

Development of Noncytotoxic Chitosan–Gold Nanocomposites as Efficient Antibacterial Materials

Development of Noncytotoxic Chitosan–Gold Nanocomposites as Efficient Antibacterial Materials

Naked-Eye Detection of LAMP-Produced Nucleic Acids in Saliva Using Chitosan-Capped AuNPs in a Single-Tube Assay

Naked-Eye Detection of LAMP-Produced Nucleic Acids in Saliva using Chitosan-capped AuNPs in a Single-Tube Assay

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