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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.


HNMR spectra of 0.4% gelatin solution and gelatin-Au colloid at room temperature. (1) 0.4% gelatin solution; (2) gelatin-Au colloid containing 0.4% gelatin and 0.02 M gold nanoparticles synthesized at 80°C; (3) gelatin-Au colloid containing 0.4% gelatin and 0.2 M gold nanoparticles synthesized at 80°C.
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Figure 3: HNMR spectra of 0.4% gelatin solution and gelatin-Au colloid at room temperature. (1) 0.4% gelatin solution; (2) gelatin-Au colloid containing 0.4% gelatin and 0.02 M gold nanoparticles synthesized at 80°C; (3) gelatin-Au colloid containing 0.4% gelatin and 0.2 M gold nanoparticles synthesized at 80°C.

Mentions: Figure 3 showed that there is no obvious line-width change of gelatin residual spectra in a gel state at room temperature. However, the glutamic residue spectra has an obvious change in chemical shift and the intensity before and after gelatin as reducing agent to gold(Ш). This testified that glutamic acid, a natural amino acid with a primary amine opposite carboxylate groups, acted as not only stabilizing agent but also reducing agent to form gold colloid at higher temperature. Figure 3 also showed the interaction between hydrophobic proline residue and gold nanoparticle, although their role in the mineralization process is not as well understood [27].


Biomimetic Synthesis of Gelatin Polypeptide-Assisted Noble-Metal Nanoparticles and Their Interaction Study
HNMR spectra of 0.4% gelatin solution and gelatin-Au colloid at room temperature. (1) 0.4% gelatin solution; (2) gelatin-Au colloid containing 0.4% gelatin and 0.02 M gold nanoparticles synthesized at 80°C; (3) gelatin-Au colloid containing 0.4% gelatin and 0.2 M gold nanoparticles synthesized at 80°C.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 3: HNMR spectra of 0.4% gelatin solution and gelatin-Au colloid at room temperature. (1) 0.4% gelatin solution; (2) gelatin-Au colloid containing 0.4% gelatin and 0.02 M gold nanoparticles synthesized at 80°C; (3) gelatin-Au colloid containing 0.4% gelatin and 0.2 M gold nanoparticles synthesized at 80°C.
Mentions: Figure 3 showed that there is no obvious line-width change of gelatin residual spectra in a gel state at room temperature. However, the glutamic residue spectra has an obvious change in chemical shift and the intensity before and after gelatin as reducing agent to gold(Ш). This testified that glutamic acid, a natural amino acid with a primary amine opposite carboxylate groups, acted as not only stabilizing agent but also reducing agent to form gold colloid at higher temperature. Figure 3 also showed the interaction between hydrophobic proline residue and gold nanoparticle, although their role in the mineralization process is not as well understood [27].

View Article: PubMed Central - HTML - PubMed

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.