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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.

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Comparison of BSA adsorption on apatite (Ap)-coated citric acid–stabilized cobalt ferrite (CFCA) (CFCA-Ap) surface with the Langmuir and Freundlich isotherms at pH 7.4 and 37°C.
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Figure 9: Comparison of BSA adsorption on apatite (Ap)-coated citric acid–stabilized cobalt ferrite (CFCA) (CFCA-Ap) surface with the Langmuir and Freundlich isotherms at pH 7.4 and 37°C.

Mentions: where KF and 1/n are the Freundlich characteristic constants, whose values indicate whether the absorption leads to a uniform coverage or to a heterogeneous coverage. A heterogeneous coverage would be the case if the value of 1/n is close to zero. The Freundlich expression is an empirical equation based on the adsorption on a heterogeneous surface. The relationship between the adsorption capacity and the original BSA concentration has been analyzed using both the Langmuir and the Freundlich isotherms. Figure 9 shows the fitting of BSA adsorption equilibrium on the CFCA-Ap particles at pH 7.4 and 37°C to the Langmuir and the Freundlich isotherms. The calculated Langmuir and Freundlich isothermal adsorption parameters for BSA adsorption are summarized in Table 1. The correlation coefficient (Rc) is 0.993 for the Langmuir and is 0.999 for the Freundlich isotherm. The Freundlich model fits the experimental data better than the Langmuir model when n is equal to 1. This implies that the BSA is adsorbed onto the surface of the CFCA-Ap particles in a uniform manner. This suggests that the amount of BSA protein adsorbed onto CFCA-Ap which is regulated by the concentrations of protein in the solution is in the range of 0–1.2 mg/ml.


Biomagnetic of Apatite-Coated Cobalt Ferrite: A Core – Shell Particle for Protein Adsorption and pH-Controlled Release
Comparison of BSA adsorption on apatite (Ap)-coated citric acid–stabilized cobalt ferrite (CFCA) (CFCA-Ap) surface with the Langmuir and Freundlich isotherms at pH 7.4 and 37°C.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 9: Comparison of BSA adsorption on apatite (Ap)-coated citric acid–stabilized cobalt ferrite (CFCA) (CFCA-Ap) surface with the Langmuir and Freundlich isotherms at pH 7.4 and 37°C.
Mentions: where KF and 1/n are the Freundlich characteristic constants, whose values indicate whether the absorption leads to a uniform coverage or to a heterogeneous coverage. A heterogeneous coverage would be the case if the value of 1/n is close to zero. The Freundlich expression is an empirical equation based on the adsorption on a heterogeneous surface. The relationship between the adsorption capacity and the original BSA concentration has been analyzed using both the Langmuir and the Freundlich isotherms. Figure 9 shows the fitting of BSA adsorption equilibrium on the CFCA-Ap particles at pH 7.4 and 37°C to the Langmuir and the Freundlich isotherms. The calculated Langmuir and Freundlich isothermal adsorption parameters for BSA adsorption are summarized in Table 1. The correlation coefficient (Rc) is 0.993 for the Langmuir and is 0.999 for the Freundlich isotherm. The Freundlich model fits the experimental data better than the Langmuir model when n is equal to 1. This implies that the BSA is adsorbed onto the surface of the CFCA-Ap particles in a uniform manner. This suggests that the amount of BSA protein adsorbed onto CFCA-Ap which is regulated by the concentrations of protein in the solution is in the range of 0–1.2 mg/ml.

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.