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Surface treatment of silica nanoparticles for stable and charge-controlled colloidal silica.

Kim KM, Kim HM, Lee WJ, Lee CW, Kim TI, Lee JK, Jeong J, Paek SM, Oh JM - Int J Nanomedicine (2014)

Bottom Line: Amino acid coatings resulted in relatively stable silica colloids with a modified surface charge.The time dependent change in L-arginine coated colloidal silica was investigated by measuring the pattern of the backscattered light in a Turbiscan™.The results indicated that both the 20 nm and 100 nm L-arginine coated silica samples were fairly stable in terms of colloidal homogeneity, showing only slight coalescence and sedimentation.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry and Medical Chemistry, College of Science and Technology, Yonsei University, Gangwon-do, Republic of Korea.

ABSTRACT
An attempt was made to control the surface charge of colloidal silica nanoparticles with 20 nm and 100 nm diameters. Untreated silica nanoparticles were determined to be highly negatively charged and have stable hydrodynamic sizes in a wide pH range. To change the surface to a positively charged form, various coating agents, such as amine containing molecules, multivalent metal cation, or amino acids, were used to treat the colloidal silica nanoparticles. Molecules with chelating amine sites were determined to have high affinity with the silica surface to make agglomerations or gel-like networks. Amino acid coatings resulted in relatively stable silica colloids with a modified surface charge. Three amino acid moiety coatings (L-serine, L-histidine, and L-arginine) exhibited surface charge modifying efficacy of L-histidine > L-arginine > L-serine and hydrodynamic size preservation efficacy of L-serine > L-arginine > L-histidine. The time dependent change in L-arginine coated colloidal silica was investigated by measuring the pattern of the backscattered light in a Turbiscan™. The results indicated that both the 20 nm and 100 nm L-arginine coated silica samples were fairly stable in terms of colloidal homogeneity, showing only slight coalescence and sedimentation.

No MeSH data available.


Zeta potential and hydrodynamic size of silica nanoparticles coated with L-arginine.Notes: (A) Zeta potential of colloidal silica nanoparticles with 20 nm diameter, (B) hydrodynamic size of colloidal silica nanoparticles with 20 nm diameter, (C) zeta potential of colloidal silica nanoparticles with 100 nm diameter, and (D) hydrodynamic size of colloidal silica nanoparticles with 100 nm diameter at pH 5.5, 6.0, and 6.5, and pristine silica depending on the time, respectively. Open or solid squares/triangles/circles represent L-arginine coated or uncoated samples at pH 5.5, 6.0, and 6.5, respectively.
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f5-ijn-9-029: Zeta potential and hydrodynamic size of silica nanoparticles coated with L-arginine.Notes: (A) Zeta potential of colloidal silica nanoparticles with 20 nm diameter, (B) hydrodynamic size of colloidal silica nanoparticles with 20 nm diameter, (C) zeta potential of colloidal silica nanoparticles with 100 nm diameter, and (D) hydrodynamic size of colloidal silica nanoparticles with 100 nm diameter at pH 5.5, 6.0, and 6.5, and pristine silica depending on the time, respectively. Open or solid squares/triangles/circles represent L-arginine coated or uncoated samples at pH 5.5, 6.0, and 6.5, respectively.

Mentions: Figure 5 displays the time dependent zeta potential and hydrodynamic size changes of SiO2EN20(R) and SiO2EN100(R) with respect to the pH condition. The 20 nm colloidal silica exhibited clear zeta potential increases of approximately 10, 20, and 15 mV upon L-arg coating. The hydrodynamic size showed a time dependent gradual increase. The final hydrodynamic sizes of SiO2EN20(−) after 48 hours of L-arg coating were determined to be 27.9±0.4 nm, 30.4±0.7 nm, and 53.5±0.9 nm for pH 6.5, 6.0, and 5.5, respectively. Although partial agglomeration of the SiO2EN20(R) sample was observed, the degree of agglomeration was not significant compared with the SiO2EN20(H), which showed 600–700 nm hydrodynamic sizes after 48 hours. The 100 nm colloidal silica also showed a zeta potential increase with the L-arg treatment. The zeta potential differences before and after coating were approximately 15 mV at pH 5.5 and approximately 10 mV at pH 6.0 and 6.5. SiO2EN100(−) showed almost no change in hydrodynamic size during its 48 hour L-arg coating, suggesting high colloidal stability upon L-arg treatment.


Surface treatment of silica nanoparticles for stable and charge-controlled colloidal silica.

Kim KM, Kim HM, Lee WJ, Lee CW, Kim TI, Lee JK, Jeong J, Paek SM, Oh JM - Int J Nanomedicine (2014)

Zeta potential and hydrodynamic size of silica nanoparticles coated with L-arginine.Notes: (A) Zeta potential of colloidal silica nanoparticles with 20 nm diameter, (B) hydrodynamic size of colloidal silica nanoparticles with 20 nm diameter, (C) zeta potential of colloidal silica nanoparticles with 100 nm diameter, and (D) hydrodynamic size of colloidal silica nanoparticles with 100 nm diameter at pH 5.5, 6.0, and 6.5, and pristine silica depending on the time, respectively. Open or solid squares/triangles/circles represent L-arginine coated or uncoated samples at pH 5.5, 6.0, and 6.5, respectively.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4279762&req=5

f5-ijn-9-029: Zeta potential and hydrodynamic size of silica nanoparticles coated with L-arginine.Notes: (A) Zeta potential of colloidal silica nanoparticles with 20 nm diameter, (B) hydrodynamic size of colloidal silica nanoparticles with 20 nm diameter, (C) zeta potential of colloidal silica nanoparticles with 100 nm diameter, and (D) hydrodynamic size of colloidal silica nanoparticles with 100 nm diameter at pH 5.5, 6.0, and 6.5, and pristine silica depending on the time, respectively. Open or solid squares/triangles/circles represent L-arginine coated or uncoated samples at pH 5.5, 6.0, and 6.5, respectively.
Mentions: Figure 5 displays the time dependent zeta potential and hydrodynamic size changes of SiO2EN20(R) and SiO2EN100(R) with respect to the pH condition. The 20 nm colloidal silica exhibited clear zeta potential increases of approximately 10, 20, and 15 mV upon L-arg coating. The hydrodynamic size showed a time dependent gradual increase. The final hydrodynamic sizes of SiO2EN20(−) after 48 hours of L-arg coating were determined to be 27.9±0.4 nm, 30.4±0.7 nm, and 53.5±0.9 nm for pH 6.5, 6.0, and 5.5, respectively. Although partial agglomeration of the SiO2EN20(R) sample was observed, the degree of agglomeration was not significant compared with the SiO2EN20(H), which showed 600–700 nm hydrodynamic sizes after 48 hours. The 100 nm colloidal silica also showed a zeta potential increase with the L-arg treatment. The zeta potential differences before and after coating were approximately 15 mV at pH 5.5 and approximately 10 mV at pH 6.0 and 6.5. SiO2EN100(−) showed almost no change in hydrodynamic size during its 48 hour L-arg coating, suggesting high colloidal stability upon L-arg treatment.

Bottom Line: Amino acid coatings resulted in relatively stable silica colloids with a modified surface charge.The time dependent change in L-arginine coated colloidal silica was investigated by measuring the pattern of the backscattered light in a Turbiscan™.The results indicated that both the 20 nm and 100 nm L-arginine coated silica samples were fairly stable in terms of colloidal homogeneity, showing only slight coalescence and sedimentation.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry and Medical Chemistry, College of Science and Technology, Yonsei University, Gangwon-do, Republic of Korea.

ABSTRACT
An attempt was made to control the surface charge of colloidal silica nanoparticles with 20 nm and 100 nm diameters. Untreated silica nanoparticles were determined to be highly negatively charged and have stable hydrodynamic sizes in a wide pH range. To change the surface to a positively charged form, various coating agents, such as amine containing molecules, multivalent metal cation, or amino acids, were used to treat the colloidal silica nanoparticles. Molecules with chelating amine sites were determined to have high affinity with the silica surface to make agglomerations or gel-like networks. Amino acid coatings resulted in relatively stable silica colloids with a modified surface charge. Three amino acid moiety coatings (L-serine, L-histidine, and L-arginine) exhibited surface charge modifying efficacy of L-histidine > L-arginine > L-serine and hydrodynamic size preservation efficacy of L-serine > L-arginine > L-histidine. The time dependent change in L-arginine coated colloidal silica was investigated by measuring the pattern of the backscattered light in a Turbiscan™. The results indicated that both the 20 nm and 100 nm L-arginine coated silica samples were fairly stable in terms of colloidal homogeneity, showing only slight coalescence and sedimentation.

No MeSH data available.