One-step synthesis of hydrophobized gold nanoparticles of controllable size by the reduction of aqueous chloroaurate ions by hexadecylaniline at the liquid–liquid interface

Selvakannan, P. R.; Mandal, Saikat; Pasricha, Renu; Adyanthaya, Suguna; Sastry, Murali

doi:10.1039/b203438g

Cited by 102 publications

(82 citation statements)

References 11 publications

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“…After stirring the colloidal gold solution with the zeolite for 12 h, there was loss in the intensity of surface plasmon resonance due to the decrease in concentration of gold nanoparticles in the aqueous solution (curve 2). This clearly indicates binding of the gold nanoparticles to the amine-functionalized zeolite through free amine groups of APTS (Brown and Hutchison et al, 1999;Kumar et al, 2000;Leff et al, 1996;Sastry et al, 2001;Selvakannan et al, 2002). The mass loading of the gold nanoparticles on the zeolite was estimated as 5 wt%.…”

Section: Resultsmentioning

confidence: 99%

Immobilization and biocatalytic activity of fungal protease on gold nanoparticle‐loaded zeolite microspheres

Phadtare

Vinod

Mukhopadhyay

et al. 2004

Biotech & Bioengineering

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Gold nanoparticles are excellent biocompatible surfaces for the immobilization of enzymes. However, separation of the gold nanoparticle-enzyme bioconjugate material from the reaction medium is often difficult. In this study, we investigate the assembly of the gold nanoparticles on the surface of the amine-functionalized zeolite microspheres in the formation of zeolite-gold nanoparticle "core-shell" structures and, thereafter, the use of this structure in immobilization of fungal protease. The assembly of gold nanoparticles on the zeolite surface occurs through the amine groups present in 3-aminopropyltrimethoxysilane (3-APTS). The fungal proteases bound to the massive "core-shell" structures were easily separated from the reaction medium by mild centrifugation and exhibited excellent reuse characteristics. The biocatalytic activity of fungal protease in the bioconjugate was marginally enhanced relative to the free enzyme in solution. The bioconjugate material also showed significantly enhanced pH and temperature stability and a shift in the optimum temperature of operation.

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Section: Resultsmentioning

confidence: 99%

Immobilization and biocatalytic activity of fungal protease on gold nanoparticle‐loaded zeolite microspheres

Phadtare

Vinod

Mukhopadhyay

et al. 2004

Biotech & Bioengineering

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“…It is well known that amine groups can easily protonate in acidic or neutral solution and transfer electrons to gold ions (Au 3+ ), leading to the formation of Au 0 (nuclei)/ Au-amine complexes via simple amine chemistry. [55][56][57][58][59][60] The synthesis of gold nanoparticles of different sizes is a kinetically driven process. 54 Increasing the reaction temperature during the reduction of gold ions (AuCl 4 À ) using cefaclor leads to an increase in the rate of reduction of the gold ions, which promotes an enhanced nucleation rate with the formation of a large population of nuclei.…”

Section: Resultsmentioning

confidence: 99%

Antibiotic mediated synthesis of gold nanoparticles with potent antimicrobial activity and their application in antimicrobial coatings

2010

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We report a one-pot synthesis of spherical gold nanoparticles (52-22 nm) and their capping with cefaclor, a second-generation antibiotic, without use of other chemicals. The differently sized gold nanoparticles were fabricated by controlling the rate of reduction of gold ions in aqueous solution by varying the reaction temperature (20-70 C). The primary amine group of cefaclor acted as both the reducing and capping agent for the synthesis of gold nanoparticles leaving the b-lactam ring of cefaclor available for activity against microbes. Antimicrobial testing showed that cefaclor reduced gold nanoparticles have potent antimicrobial activity against both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria as compared to cefaclor or gold nanoparticles alone. The minimum inhibition concentrations (MICs) of cefaclor reduced gold nanoparticles were 10 mg mL À1and 100 mg mL À1 for S. aureus and E. coli respectively. The cefaclor reduced gold nanoparticles were further coated onto poly(ethyleneimine) (PEI) modified glass surfaces to obtain antimicrobial coatings suitable for biomedical applications and were tested against E. coli as an exemplar of activity. The antimicrobial coatings were very robust under adverse conditions (pH 3 and 10), inhibited the growth of E. coli on their surfaces, and could be used many times with retained activity. Results from a combined spectroscopic (FTIR) and microscopic study (AFM) suggest that the action of these novel particles is through the combined action of cefaclor inhibiting the synthesis of the peptidoglycan layer and gold nanoparticles generating ''holes'' in bacterial cell walls thereby increasing the permeability of the cell wall, resulting in the leakage of cell contents and eventually cell death.

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“…When Michael Faraday (Faraday, 1857) described the synthesis of gold nanoparticles in 1857 from a gold (III) salt he used phosphorus dispersed into ether or carbon disulphide as the reductant. Since then numerous methods have been described for preparing monodisperse nanoparticulate gold formulations of defined sizes and shapes in both aqueous (Mellor, 1923;Turkevich et al, 1954;Handley, 1989;Henglein, 1999) and organic environments (Brust et al, 1994;Selvakannan et al, 2002;Bartlett et al, 1978), generally using chemical methods to reduce gold (III) complexes such as hydrogen tetrachloroaurate (HAuCl 4 ). Table 1 indicates some representative preparative methods affording particles of defined size (after Handley, 1989).…”

Section: Preparation Of Colloidal Goldmentioning

confidence: 99%

Colloidal metallic gold is not bio-inert

et al. 2008

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Metallic gold (Au degrees ) is a likely biotransformation product of monovalent gold, Au(I) whenever it is dissociated from in vivo ligands, Au degrees being formed either by bioreduction or by spontaneous dismutation (with co-production of trivalent gold). This review discusses the preparation and some biologically relevant properties of colloidal metallic gold (CMG) in its nano-particulate form. Tyndall's purple, a well characterised preparation of CMG, shows potent anti-arthritic activity in rats, approximately 10(3) times that of sodium aurothiomalate (Myocrysin). Even more remarkable is its broader spectrum of action in rats compared to this classic DMARD.

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One-step synthesis of hydrophobized gold nanoparticles of controllable size by the reduction of aqueous chloroaurate ions by hexadecylaniline at the liquid–liquid interface

Cited by 102 publications

References 11 publications

Immobilization and biocatalytic activity of fungal protease on gold nanoparticle‐loaded zeolite microspheres

Immobilization and biocatalytic activity of fungal protease on gold nanoparticle‐loaded zeolite microspheres

Antibiotic mediated synthesis of gold nanoparticles with potent antimicrobial activity and their application in antimicrobial coatings

Colloidal metallic gold is not bio-inert

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