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Biomagnetic of Apatite-Coated Cobalt Ferrite: A Core – Shell Particle for Protein Adsorption and pH-Controlled Release

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ABSTRACT

Magnetic nanoparticle composite with a cobalt ferrite (CoFe2O4, (CF)) core and an apatite (Ap) coating was synthesized using a biomineralization process in which a modified simulated body fluid (1.5SBF) solution is the source of the calcium phosphate for the apatite formation. The core–shell structure formed after the citric acid–stabilized cobalt ferrite (CFCA) particles were incubated in the 1.5 SBF solution for 1 week. The mean particle size of CFCA-Ap is about 750 nm. A saturation magnetization of 15.56 emug-1 and a coercivity of 1808.5 Oe were observed for the CFCA-Ap obtained. Bovine serum albumin (BSA) was used as the model protein to study the adsorption and release of the proteins by the CFCA-Ap particles. The protein adsorption by the CFCA-Ap particles followed a more typical Freundlich than Langmuir adsorption isotherm. The BSA release as a function of time became less rapid as the CFCA-Ap particles were immersed in higher pH solution, thus indicating that the BSA release is dependent on the local pH.

No MeSH data available.


Zeta-potential of citric stabilize cobalt ferrite (CFCA) particles.
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Figure 2: Zeta-potential of citric stabilize cobalt ferrite (CFCA) particles.

Mentions: The formation of the calcium phosphate layer on the CFCA surface during the immersion of the CFCA particles in the SBF solution involves both the nucleation and growth of inorganic apatite mineral. The negative charge on the CFCA particles causes the calcium and phosphate ions present in the 1.5SBF solution to accumulate on the surfaces of the CFCA particles. On Figure 2, we have plotted the zeta-potential (ζ) of CFCA particle measured with the Zetasizer Nano ZS. It gives a negatively charged surface value of -15.69. The XRD patterns and FT-IR spectrums of the particles are shown in Figure 3. Figure 3a shows the diffraction pattern of the CF particle. The diffraction peaks at the Bragg angles at 30.2°, 35.7°, 43.6°, 53.6°, and 57.3° (represented by F letter) are the reflection peaks from the (220), (311), (400), (511), and (440) lattice planes, which are the peaks of cobalt ferrite [22,23,33,34]. The XRD pattern of CFCA after being incubated in SBF is shown in Figure 3b. The patterns of cobalt ferrite and the peak pattern of calcium phosphate of hydroxyapatite (HAp) [28,29] at 2θ ~ 26°, 28°, and 30–32° are seen. Evidence of hydroxyapatite formed on the CFCA particles can be seen in the FT-IR reflection spectra. The FT-IR spectrums of CFCA-CaP are shown in Figure 3c. The characteristic bands of PO43- groups in the apatite can be seen in the FT-IR spectrum of the CFCA-Ap particles. The intense bands at 1,088, 1,035, and 961 cm-1 are due to the PO43- stretching modes, while the doublet at 602 and 562 cm-1 are due to the PO43- bending mode [29]. The shoulder signals around 1,450 and 1,240 cm-1 and the doublet peaks around 873 cm-1 are characteristics of carbonated ions substituted into the phosphate site in an apatite structure, the so-called B-type apatite [39].


Biomagnetic of Apatite-Coated Cobalt Ferrite: A Core – Shell Particle for Protein Adsorption and pH-Controlled Release
Zeta-potential of citric stabilize cobalt ferrite (CFCA) particles.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211243&req=5

Figure 2: Zeta-potential of citric stabilize cobalt ferrite (CFCA) particles.
Mentions: The formation of the calcium phosphate layer on the CFCA surface during the immersion of the CFCA particles in the SBF solution involves both the nucleation and growth of inorganic apatite mineral. The negative charge on the CFCA particles causes the calcium and phosphate ions present in the 1.5SBF solution to accumulate on the surfaces of the CFCA particles. On Figure 2, we have plotted the zeta-potential (ζ) of CFCA particle measured with the Zetasizer Nano ZS. It gives a negatively charged surface value of -15.69. The XRD patterns and FT-IR spectrums of the particles are shown in Figure 3. Figure 3a shows the diffraction pattern of the CF particle. The diffraction peaks at the Bragg angles at 30.2°, 35.7°, 43.6°, 53.6°, and 57.3° (represented by F letter) are the reflection peaks from the (220), (311), (400), (511), and (440) lattice planes, which are the peaks of cobalt ferrite [22,23,33,34]. The XRD pattern of CFCA after being incubated in SBF is shown in Figure 3b. The patterns of cobalt ferrite and the peak pattern of calcium phosphate of hydroxyapatite (HAp) [28,29] at 2θ ~ 26°, 28°, and 30–32° are seen. Evidence of hydroxyapatite formed on the CFCA particles can be seen in the FT-IR reflection spectra. The FT-IR spectrums of CFCA-CaP are shown in Figure 3c. The characteristic bands of PO43- groups in the apatite can be seen in the FT-IR spectrum of the CFCA-Ap particles. The intense bands at 1,088, 1,035, and 961 cm-1 are due to the PO43- stretching modes, while the doublet at 602 and 562 cm-1 are due to the PO43- bending mode [29]. The shoulder signals around 1,450 and 1,240 cm-1 and the doublet peaks around 873 cm-1 are characteristics of carbonated ions substituted into the phosphate site in an apatite structure, the so-called B-type apatite [39].

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Magnetic nanoparticle composite with a cobalt ferrite (CoFe2O4, (CF)) core and an apatite (Ap) coating was synthesized using a biomineralization process in which a modified simulated body fluid (1.5SBF) solution is the source of the calcium phosphate for the apatite formation. The core–shell structure formed after the citric acid–stabilized cobalt ferrite (CFCA) particles were incubated in the 1.5 SBF solution for 1 week. The mean particle size of CFCA-Ap is about 750 nm. A saturation magnetization of 15.56 emug-1 and a coercivity of 1808.5 Oe were observed for the CFCA-Ap obtained. Bovine serum albumin (BSA) was used as the model protein to study the adsorption and release of the proteins by the CFCA-Ap particles. The protein adsorption by the CFCA-Ap particles followed a more typical Freundlich than Langmuir adsorption isotherm. The BSA release as a function of time became less rapid as the CFCA-Ap particles were immersed in higher pH solution, thus indicating that the BSA release is dependent on the local pH.

No MeSH data available.