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Biomimetic Synthesis of Gelatin Polypeptide-Assisted Noble-Metal Nanoparticles and Their Interaction Study

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ABSTRACT

Herein, the generation of gold, silver, and silver–gold (Ag–Au) bimetallic nanoparticles was carried out in collagen (gelatin) solution. It first showed that the major ingredient in gelatin polypeptide, glutamic acid, acted as reducing agent to biomimetically synthesize noble metal nanoparticles at 80°C. The size of nanoparticles can be controlled not only by the mass ratio of gelatin to gold ion but also by pH of gelatin solution. Interaction between noble-metal nanoparticles and polypeptide has been investigated by TEM, UV–visible, fluorescence spectroscopy, and HNMR. This study testified that the degradation of gelatin protein could not alter the morphology of nanoparticles, but it made nanoparticles aggregated clusters array (opposing three-dimensional α-helix folding structure) into isolated nanoparticles stabilized by gelatin residues. This is a promising merit of gelatin to apply in the synthesis of nanoparticles. Therefore, gelatin protein is an excellent template for biomimetic synthesis of noble metal/bimetallic nanoparticle growth to form nanometer-sized device.

No MeSH data available.


a Relation between the reaction time and temperature (Cgelatin: 0.4 wt%), The reaction time was determined by UV–vis spectra. When the typical absorption band of gold nanoparticle was stable, the reaction is considered to be over; b UV–vis spectra of gelatin-AuNPs colloids synthesized at different temperature (1) 100°C, (2) 80°C, (3) 60°C.
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Figure 2: a Relation between the reaction time and temperature (Cgelatin: 0.4 wt%), The reaction time was determined by UV–vis spectra. When the typical absorption band of gold nanoparticle was stable, the reaction is considered to be over; b UV–vis spectra of gelatin-AuNPs colloids synthesized at different temperature (1) 100°C, (2) 80°C, (3) 60°C.

Mentions: The amino acid analysis of gelatin is variable, particularly for the minor constituents, depending on raw materials and processes used, proximate values by weight are [23]: glycine 21%, proline 12%, hydroxyproline 12%, glutamic acid 10%, alanine 9%, arginine 8%, aspartic acid 6%, lysine 4%, serine 4%, leucine 3%, valine 2%, phenylalanine 2%, threonine 2%, isoleucine 1%, hydroxylysine 1%, methionine and histidine <1% with tyrosine <0.5% in which methionine [24,25], lysine [10], tyrosine [11] have strong electron-donating properties, which are currently being utilized for the reduction of the Au(III) ion to form Au(0) colloid at room temperature separately. Gold nanoparticles can also be prepared by using glutamic acid upon thermal reduction method [26]. As the ingredient of gelatin polypeptide, methionine [24,25], lysine [10], tyrosine [11] is very little, it took a week for gelatin to reduce Au(III) ion to form metallic Au at room temperature (see Figure 2a). However, HAuCl4 can be easily reduced by gelatin polypeptide at higher temperature (>60°C). This may be due to the major ingredient as reducing agent at higher temperature.


Biomimetic Synthesis of Gelatin Polypeptide-Assisted Noble-Metal Nanoparticles and Their Interaction Study
a Relation between the reaction time and temperature (Cgelatin: 0.4 wt%), The reaction time was determined by UV–vis spectra. When the typical absorption band of gold nanoparticle was stable, the reaction is considered to be over; b UV–vis spectra of gelatin-AuNPs colloids synthesized at different temperature (1) 100°C, (2) 80°C, (3) 60°C.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211277&req=5

Figure 2: a Relation between the reaction time and temperature (Cgelatin: 0.4 wt%), The reaction time was determined by UV–vis spectra. When the typical absorption band of gold nanoparticle was stable, the reaction is considered to be over; b UV–vis spectra of gelatin-AuNPs colloids synthesized at different temperature (1) 100°C, (2) 80°C, (3) 60°C.
Mentions: The amino acid analysis of gelatin is variable, particularly for the minor constituents, depending on raw materials and processes used, proximate values by weight are [23]: glycine 21%, proline 12%, hydroxyproline 12%, glutamic acid 10%, alanine 9%, arginine 8%, aspartic acid 6%, lysine 4%, serine 4%, leucine 3%, valine 2%, phenylalanine 2%, threonine 2%, isoleucine 1%, hydroxylysine 1%, methionine and histidine <1% with tyrosine <0.5% in which methionine [24,25], lysine [10], tyrosine [11] have strong electron-donating properties, which are currently being utilized for the reduction of the Au(III) ion to form Au(0) colloid at room temperature separately. Gold nanoparticles can also be prepared by using glutamic acid upon thermal reduction method [26]. As the ingredient of gelatin polypeptide, methionine [24,25], lysine [10], tyrosine [11] is very little, it took a week for gelatin to reduce Au(III) ion to form metallic Au at room temperature (see Figure 2a). However, HAuCl4 can be easily reduced by gelatin polypeptide at higher temperature (>60°C). This may be due to the major ingredient as reducing agent at higher temperature.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Herein, the generation of gold, silver, and silver&ndash;gold (Ag&ndash;Au) bimetallic nanoparticles was carried out in collagen (gelatin) solution. It first showed that the major ingredient in gelatin polypeptide, glutamic acid, acted as reducing agent to biomimetically synthesize noble metal nanoparticles at 80&deg;C. The size of nanoparticles can be controlled not only by the mass ratio of gelatin to gold ion but also by pH of gelatin solution. Interaction between noble-metal nanoparticles and polypeptide has been investigated by TEM, UV&ndash;visible, fluorescence spectroscopy, and HNMR. This study testified that the degradation of gelatin protein could not alter the morphology of nanoparticles, but it made nanoparticles aggregated clusters array (opposing three-dimensional &alpha;-helix folding structure) into isolated nanoparticles stabilized by gelatin residues. This is a promising merit of gelatin to apply in the synthesis of nanoparticles. Therefore, gelatin protein is an excellent template for biomimetic synthesis of noble metal/bimetallic nanoparticle growth to form nanometer-sized device.

No MeSH data available.