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Facile synthesis of folate-conjugated magnetic/fluorescent bifunctional microspheres.

Shen M, Jia W, Lin C, Fan G, Jin Y, Chen X, Chen G - Nanoscale Res Lett (2014)

Bottom Line: The preparation procedure included the preparation of chitosan-coated Fe3O4 nanoparticles (CS-coated Fe3O4 NPs) prepared by a one-pot solvothermal method, the reaction between carboxylic and amino groups under activation of NHS and EDC in order to obtain the CdTe-CS-coated Fe3O4 NPs, and finally the growth of SiO2 shell vent the photoluminescence (PL) quenching via a Stöber method (Fe3O4-CdTe@SiO2).Moreover, in order to have a specific targeting capacity, the magnetic and fluorescent bifunctional microspheres were synthesized by bonding of SiO2 shell with FA molecules via amide reaction (Fe3O4-CdTe@SiO2-FA).The morphology, size, chemical components, and magnetic property of as-prepared composite nanoparticles were characterized by ultraviolet-visible spectroscopy, fluorescent spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), scanning transmission electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and vibrating sample magnetometer (VSM), respectively.

View Article: PubMed Central - HTML - PubMed

Affiliation: College of Pharmaceutical and Chemical Engineering, Taizhou University, Jiaojiang 318000, People's Republic of China.

ABSTRACT
In this paper, we investigated the functional imaging properties of magnetic microspheres composed of magnetic core and CdTe quantum dots in the silica shell functionalized with folic acid (FA). The preparation procedure included the preparation of chitosan-coated Fe3O4 nanoparticles (CS-coated Fe3O4 NPs) prepared by a one-pot solvothermal method, the reaction between carboxylic and amino groups under activation of NHS and EDC in order to obtain the CdTe-CS-coated Fe3O4 NPs, and finally the growth of SiO2 shell vent the photoluminescence (PL) quenching via a Stöber method (Fe3O4-CdTe@SiO2). Moreover, in order to have a specific targeting capacity, the magnetic and fluorescent bifunctional microspheres were synthesized by bonding of SiO2 shell with FA molecules via amide reaction (Fe3O4-CdTe@SiO2-FA). The morphology, size, chemical components, and magnetic property of as-prepared composite nanoparticles were characterized by ultraviolet-visible spectroscopy, fluorescent spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), scanning transmission electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and vibrating sample magnetometer (VSM), respectively. The results show that the magnetic and fluorescent bifunctional microspheres have strong luminescent which will be employed for immuno-labeling and fluorescent imaging of HeLa cells.

No MeSH data available.


The zeta potential of as-prepared samples at pH =7.0: (a) naked Fe3O4 NPs, (b) CS-coated Fe3O4 NPs, (c) CdTe-CS-coated Fe3O4 NPs, and (d) Fe3O4-CdTe@SiO2-NH2 NPs.
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Figure 7: The zeta potential of as-prepared samples at pH =7.0: (a) naked Fe3O4 NPs, (b) CS-coated Fe3O4 NPs, (c) CdTe-CS-coated Fe3O4 NPs, and (d) Fe3O4-CdTe@SiO2-NH2 NPs.

Mentions: The electrostatic interaction of the nanoparticles can be controlled by variation in their surface charges, which can be determined by measuring the zeta potential of these particles. Compared with naked Fe3O4 NPs (Figure 7a), the zeta potential of CS-coated Fe3O4 NPs possessed higher positive charge (Figure 7b). This may be caused by the protonation of the amino group (-NH2) in the chitosan. On the other hand, after coating CdTe QDs on the surface of CS-coated Fe3O4 NPs, the zeta-potential decreased from +37.2 to -16.4 as expected. Because CdTe QDs was conjugated to the amino group of CS, they neutralized the positive charge of CS. Besides, as-prepared CdTe QDs are strongly negatively charged moieties. As shown in Figure 7d, the zeta-potential was changed to about +19.6 after coated with SiO2-NH2 shell. This result indicates that CdTe-CS-coated Fe3O4 NPs could be successfully coated with SiO2-NH2 shell.


Facile synthesis of folate-conjugated magnetic/fluorescent bifunctional microspheres.

Shen M, Jia W, Lin C, Fan G, Jin Y, Chen X, Chen G - Nanoscale Res Lett (2014)

The zeta potential of as-prepared samples at pH =7.0: (a) naked Fe3O4 NPs, (b) CS-coated Fe3O4 NPs, (c) CdTe-CS-coated Fe3O4 NPs, and (d) Fe3O4-CdTe@SiO2-NH2 NPs.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4199784&req=5

Figure 7: The zeta potential of as-prepared samples at pH =7.0: (a) naked Fe3O4 NPs, (b) CS-coated Fe3O4 NPs, (c) CdTe-CS-coated Fe3O4 NPs, and (d) Fe3O4-CdTe@SiO2-NH2 NPs.
Mentions: The electrostatic interaction of the nanoparticles can be controlled by variation in their surface charges, which can be determined by measuring the zeta potential of these particles. Compared with naked Fe3O4 NPs (Figure 7a), the zeta potential of CS-coated Fe3O4 NPs possessed higher positive charge (Figure 7b). This may be caused by the protonation of the amino group (-NH2) in the chitosan. On the other hand, after coating CdTe QDs on the surface of CS-coated Fe3O4 NPs, the zeta-potential decreased from +37.2 to -16.4 as expected. Because CdTe QDs was conjugated to the amino group of CS, they neutralized the positive charge of CS. Besides, as-prepared CdTe QDs are strongly negatively charged moieties. As shown in Figure 7d, the zeta-potential was changed to about +19.6 after coated with SiO2-NH2 shell. This result indicates that CdTe-CS-coated Fe3O4 NPs could be successfully coated with SiO2-NH2 shell.

Bottom Line: The preparation procedure included the preparation of chitosan-coated Fe3O4 nanoparticles (CS-coated Fe3O4 NPs) prepared by a one-pot solvothermal method, the reaction between carboxylic and amino groups under activation of NHS and EDC in order to obtain the CdTe-CS-coated Fe3O4 NPs, and finally the growth of SiO2 shell vent the photoluminescence (PL) quenching via a Stöber method (Fe3O4-CdTe@SiO2).Moreover, in order to have a specific targeting capacity, the magnetic and fluorescent bifunctional microspheres were synthesized by bonding of SiO2 shell with FA molecules via amide reaction (Fe3O4-CdTe@SiO2-FA).The morphology, size, chemical components, and magnetic property of as-prepared composite nanoparticles were characterized by ultraviolet-visible spectroscopy, fluorescent spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), scanning transmission electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and vibrating sample magnetometer (VSM), respectively.

View Article: PubMed Central - HTML - PubMed

Affiliation: College of Pharmaceutical and Chemical Engineering, Taizhou University, Jiaojiang 318000, People's Republic of China.

ABSTRACT
In this paper, we investigated the functional imaging properties of magnetic microspheres composed of magnetic core and CdTe quantum dots in the silica shell functionalized with folic acid (FA). The preparation procedure included the preparation of chitosan-coated Fe3O4 nanoparticles (CS-coated Fe3O4 NPs) prepared by a one-pot solvothermal method, the reaction between carboxylic and amino groups under activation of NHS and EDC in order to obtain the CdTe-CS-coated Fe3O4 NPs, and finally the growth of SiO2 shell vent the photoluminescence (PL) quenching via a Stöber method (Fe3O4-CdTe@SiO2). Moreover, in order to have a specific targeting capacity, the magnetic and fluorescent bifunctional microspheres were synthesized by bonding of SiO2 shell with FA molecules via amide reaction (Fe3O4-CdTe@SiO2-FA). The morphology, size, chemical components, and magnetic property of as-prepared composite nanoparticles were characterized by ultraviolet-visible spectroscopy, fluorescent spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), scanning transmission electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and vibrating sample magnetometer (VSM), respectively. The results show that the magnetic and fluorescent bifunctional microspheres have strong luminescent which will be employed for immuno-labeling and fluorescent imaging of HeLa cells.

No MeSH data available.