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Physicochemical properties of surface charge-modified ZnO nanoparticles with different particle sizes.

Kim KM, Choi MH, Lee JK, Jeong J, Kim YR, Kim MK, Paek SM, Oh JM - Int J Nanomedicine (2014)

Bottom Line: The coating agents were determined to have attached to the ZnO surfaces through either electrostatic interaction or partial coordination bonding.Electrokinetic measurements showed that the surface charges of the ZnO nanoparticles were successfully modified to be negative (about -40 mV) or positive (about +25 mV).Although all the four types of ZnO nanoparticles showed some agglomeration when suspended in water according to dynamic light scattering analysis, they had clearly distinguishable particle size and surface charge parameters and well defined physicochemical properties.

View Article: PubMed Central - PubMed

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

ABSTRACT
In this study, four types of standardized ZnO nanoparticles were prepared for assessment of their potential biological risk. Powder-phased ZnO nanoparticles with different particle sizes (20 nm and 100 nm) were coated with citrate or L-serine to induce a negative or positive surface charge, respectively. The four types of coated ZnO nanoparticles were subjected to physicochemical evaluation according to the guidelines published by the Organisation for Economic Cooperation and Development. All four samples had a well crystallized Wurtzite phase, with particle sizes of ∼30 nm and ∼70 nm after coating with organic molecules. The coating agents were determined to have attached to the ZnO surfaces through either electrostatic interaction or partial coordination bonding. Electrokinetic measurements showed that the surface charges of the ZnO nanoparticles were successfully modified to be negative (about -40 mV) or positive (about +25 mV). Although all the four types of ZnO nanoparticles showed some agglomeration when suspended in water according to dynamic light scattering analysis, they had clearly distinguishable particle size and surface charge parameters and well defined physicochemical properties.

No MeSH data available.


Related in: MedlinePlus

Fourier transform infrared spectra in the ranges of (A) 4,000–450, (B) 1,710–1,490, (C) 1,490–1,320, and (D) 1,250–950 cm−1 for (a) ZnOSM20(−), (b) ZnOSM20(+), (c) ZnOAE100(−), and (d) ZnOAE100(+).Notes: The dotted and solid lines of the pristine and multipeaks fit the spectra shown in (B), (C), and (D).Abbreviations: ν, bond stretching; δ, bending; ω, wagging; γ, rocking (out of plane); asym, asymmetric; sym, symmetric.
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f6-ijn-9-041: Fourier transform infrared spectra in the ranges of (A) 4,000–450, (B) 1,710–1,490, (C) 1,490–1,320, and (D) 1,250–950 cm−1 for (a) ZnOSM20(−), (b) ZnOSM20(+), (c) ZnOAE100(−), and (d) ZnOAE100(+).Notes: The dotted and solid lines of the pristine and multipeaks fit the spectra shown in (B), (C), and (D).Abbreviations: ν, bond stretching; δ, bending; ω, wagging; γ, rocking (out of plane); asym, asymmetric; sym, symmetric.

Mentions: The infrared spectra (Figure 6), in conjunction with the XPS and NMR spectra, provided the chemical information on both the inorganic ZnO material and the organic coating molecules, ie, citrate and L-serine. The infrared spectra for all four types of coated ZnO nanoparticles showed the expected absorption peaks corresponding to the chemical bonds existing in the ZnO or coating agents. As shown in Figure 6A, all four samples exhibited clear peaks at around 3,500 cm−1 and 490 cm−1, which were attributable to the ν(−OH) and ν(Zn–O) stretching vibration modes coming from the cores of the ZnO nanoparticles. Figure 6B–D shows the magnified spectra from the dotted box in Figure 6A, and the merged peaks were separated using the Gaussian multipeak separation function of OriginPro 8 version 8.0724. Each separated peak reflects the characteristic chemical bonds of the organic moieties. In the spectra for the L-serine-coated samples ((b) ZnOSM20(+) and (d) ZnOAE100(+)), the amine-originated bands, ie, δasym(NH3+) and γ(NH3+), could be observed at 1,656 cm−1 and 1,120 cm−1, respectively. The characteristic peaks of amino acids, ie, ω(CH2) at around 1,395 cm−1, δ(COH) at around 1,207 cm−1, and ν(CO) at 1,096 cm−1, were also clearly present (Table 2). When the carboxylic acids deprotonated, the infrared bands split into two peaks, ie, symmetric and asymmetric stretching vibrations. The L-serine-coated ZnO particles showed νasym(COO−) and νsym(COO−) at 1,600 cm−1 and 1420 cm−1, respectively, while the citrate-coated ZnO particles showed corresponding peaks at 1,564 cm−1 and 1,408 cm−1. The differences between νasym(COO−) and νsym(COO−), ie, (∆ν), a standard for evaluating the degree of coordination of carboxylate, were determined to be ∼180 cm−1 and ∼150 cm−1 for the L-serine coating and citrate coating, respectively.


Physicochemical properties of surface charge-modified ZnO nanoparticles with different particle sizes.

Kim KM, Choi MH, Lee JK, Jeong J, Kim YR, Kim MK, Paek SM, Oh JM - Int J Nanomedicine (2014)

Fourier transform infrared spectra in the ranges of (A) 4,000–450, (B) 1,710–1,490, (C) 1,490–1,320, and (D) 1,250–950 cm−1 for (a) ZnOSM20(−), (b) ZnOSM20(+), (c) ZnOAE100(−), and (d) ZnOAE100(+).Notes: The dotted and solid lines of the pristine and multipeaks fit the spectra shown in (B), (C), and (D).Abbreviations: ν, bond stretching; δ, bending; ω, wagging; γ, rocking (out of plane); asym, asymmetric; sym, symmetric.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4279853&req=5

f6-ijn-9-041: Fourier transform infrared spectra in the ranges of (A) 4,000–450, (B) 1,710–1,490, (C) 1,490–1,320, and (D) 1,250–950 cm−1 for (a) ZnOSM20(−), (b) ZnOSM20(+), (c) ZnOAE100(−), and (d) ZnOAE100(+).Notes: The dotted and solid lines of the pristine and multipeaks fit the spectra shown in (B), (C), and (D).Abbreviations: ν, bond stretching; δ, bending; ω, wagging; γ, rocking (out of plane); asym, asymmetric; sym, symmetric.
Mentions: The infrared spectra (Figure 6), in conjunction with the XPS and NMR spectra, provided the chemical information on both the inorganic ZnO material and the organic coating molecules, ie, citrate and L-serine. The infrared spectra for all four types of coated ZnO nanoparticles showed the expected absorption peaks corresponding to the chemical bonds existing in the ZnO or coating agents. As shown in Figure 6A, all four samples exhibited clear peaks at around 3,500 cm−1 and 490 cm−1, which were attributable to the ν(−OH) and ν(Zn–O) stretching vibration modes coming from the cores of the ZnO nanoparticles. Figure 6B–D shows the magnified spectra from the dotted box in Figure 6A, and the merged peaks were separated using the Gaussian multipeak separation function of OriginPro 8 version 8.0724. Each separated peak reflects the characteristic chemical bonds of the organic moieties. In the spectra for the L-serine-coated samples ((b) ZnOSM20(+) and (d) ZnOAE100(+)), the amine-originated bands, ie, δasym(NH3+) and γ(NH3+), could be observed at 1,656 cm−1 and 1,120 cm−1, respectively. The characteristic peaks of amino acids, ie, ω(CH2) at around 1,395 cm−1, δ(COH) at around 1,207 cm−1, and ν(CO) at 1,096 cm−1, were also clearly present (Table 2). When the carboxylic acids deprotonated, the infrared bands split into two peaks, ie, symmetric and asymmetric stretching vibrations. The L-serine-coated ZnO particles showed νasym(COO−) and νsym(COO−) at 1,600 cm−1 and 1420 cm−1, respectively, while the citrate-coated ZnO particles showed corresponding peaks at 1,564 cm−1 and 1,408 cm−1. The differences between νasym(COO−) and νsym(COO−), ie, (∆ν), a standard for evaluating the degree of coordination of carboxylate, were determined to be ∼180 cm−1 and ∼150 cm−1 for the L-serine coating and citrate coating, respectively.

Bottom Line: The coating agents were determined to have attached to the ZnO surfaces through either electrostatic interaction or partial coordination bonding.Electrokinetic measurements showed that the surface charges of the ZnO nanoparticles were successfully modified to be negative (about -40 mV) or positive (about +25 mV).Although all the four types of ZnO nanoparticles showed some agglomeration when suspended in water according to dynamic light scattering analysis, they had clearly distinguishable particle size and surface charge parameters and well defined physicochemical properties.

View Article: PubMed Central - PubMed

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

ABSTRACT
In this study, four types of standardized ZnO nanoparticles were prepared for assessment of their potential biological risk. Powder-phased ZnO nanoparticles with different particle sizes (20 nm and 100 nm) were coated with citrate or L-serine to induce a negative or positive surface charge, respectively. The four types of coated ZnO nanoparticles were subjected to physicochemical evaluation according to the guidelines published by the Organisation for Economic Cooperation and Development. All four samples had a well crystallized Wurtzite phase, with particle sizes of ∼30 nm and ∼70 nm after coating with organic molecules. The coating agents were determined to have attached to the ZnO surfaces through either electrostatic interaction or partial coordination bonding. Electrokinetic measurements showed that the surface charges of the ZnO nanoparticles were successfully modified to be negative (about -40 mV) or positive (about +25 mV). Although all the four types of ZnO nanoparticles showed some agglomeration when suspended in water according to dynamic light scattering analysis, they had clearly distinguishable particle size and surface charge parameters and well defined physicochemical properties.

No MeSH data available.


Related in: MedlinePlus