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Enhanced and selective delivery of enzyme therapy to 9L-glioma tumor via magnetic targeting of PEG-modified, β-glucosidase-conjugated iron oxide nanoparticles.

Zhou J, Zhang J, Gao W - Int J Nanomedicine (2014)

Bottom Line: The results showed that the multidomain structure and magnetization properties of these nanoparticles were conserved well throughout the synthesis steps, with an expected diameter increase and zeta potential shifts.Both magnetophoretic mobility analysis and pharmacokinetics showed improved in vitro/in vivo stability of PEG-β-Glu-MNP compared with β-Glu-MNP.In vivo magnetic targeting of PEG-β-Glu-MNP was confirmed by magnetic resonance imaging and electron spin resonance analysis in a mouse model of subcutaneous 9L-glioma.

View Article: PubMed Central - PubMed

Affiliation: Department of Urology, Hubei Hospital of Traditional Chinese Medicine, Hubei University of Chinese Medicine, Wuhan, People's Republic of China.

ABSTRACT
The stability of enzyme-conjugated magnetic iron oxide nanoparticles in plasma is of great importance for in vivo delivery of the conjugated enzyme. In this study, β-glucosidase was conjugated on aminated magnetic iron oxide nanoparticles using the glutaraldehyde method (β-Glu-MNP), and further PEGylated via N-hydroxysuccinimide chemistry. The PEG-modified, β-glucosidase-immobilized magnetic iron oxide nanoparticles (PEG-β-Glu-MNPs) were characterized by hydrodynamic diameter distribution, zeta potential, Fourier transform infrared spectroscopy, transmission electron microscopy, and a superconducting quantum interference device. The results showed that the multidomain structure and magnetization properties of these nanoparticles were conserved well throughout the synthesis steps, with an expected diameter increase and zeta potential shifts. The Michaelis constant was calculated to evaluate the activity of conjugated β-glucosidase on the magnetic iron oxide nanoparticles, indicating 73.0% and 65.4% of enzyme activity remaining for β-Glu-MNP and PEG-β-Glu-MNP, respectively. Both magnetophoretic mobility analysis and pharmacokinetics showed improved in vitro/in vivo stability of PEG-β-Glu-MNP compared with β-Glu-MNP. In vivo magnetic targeting of PEG-β-Glu-MNP was confirmed by magnetic resonance imaging and electron spin resonance analysis in a mouse model of subcutaneous 9L-glioma. Satisfactory accumulation of PEG-β-Glu-MNP in tumor tissue was successfully achieved, with an iron content of 627±45 nmol Fe/g tissue and β-glucosidase activity of 32.2±8.0 mU/g tissue.

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Lineweaver-Burk plot analysis of the enzymatic kinetics of free β-Glu, β-Glu-MNP, and PEG-β-Glu-MNP.Abbreviations: PEG, poly(ethylene glycol); β-Glu, β-glucosidase; MNP, magnetic nanoparticles; min, minutes.
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f5-ijn-9-2905: Lineweaver-Burk plot analysis of the enzymatic kinetics of free β-Glu, β-Glu-MNP, and PEG-β-Glu-MNP.Abbreviations: PEG, poly(ethylene glycol); β-Glu, β-glucosidase; MNP, magnetic nanoparticles; min, minutes.

Mentions: Corresponding Km values, indicating the affinity of the enzyme for the substrate and the maximum reaction rate (Vmax) of β-glucosidase are shown in Table 2 and Figure 5. The apparent Km value of the free enzyme was determined to be 2.23 mmol/L, and this was retained with β-Glu-MNP and PEG-β-Glu-MNP, which showed Km values of 2.27 mmol/L and 2.25 mmol/L, respectively. After conjugation, β-Glu-MNP and PEG-β-Glu-MNP showed maximum reaction rates of 23.7 μmol per minute per mg and 21.2 μmol per minute per mg, respectively, which were, respectively, about 73.0% and 65.4% that of the free enzyme (32.4 μmol per minute per mg). In our previous study,14 conjugated β-glucosidase showed maximum enzyme activity of 1.17 U/mg iron (44.1 µg enzyme/mg Fe) with an optimized feed ratio of β-glucosidase and MNP (1.45 mg protein/mg Fe). After PEGylation of β-Glu-MNP, the enzyme activity of the immobilized β-glucosidase decreased slightly to 1.05 U/mg Fe.


Enhanced and selective delivery of enzyme therapy to 9L-glioma tumor via magnetic targeting of PEG-modified, β-glucosidase-conjugated iron oxide nanoparticles.

Zhou J, Zhang J, Gao W - Int J Nanomedicine (2014)

Lineweaver-Burk plot analysis of the enzymatic kinetics of free β-Glu, β-Glu-MNP, and PEG-β-Glu-MNP.Abbreviations: PEG, poly(ethylene glycol); β-Glu, β-glucosidase; MNP, magnetic nanoparticles; min, minutes.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4061166&req=5

f5-ijn-9-2905: Lineweaver-Burk plot analysis of the enzymatic kinetics of free β-Glu, β-Glu-MNP, and PEG-β-Glu-MNP.Abbreviations: PEG, poly(ethylene glycol); β-Glu, β-glucosidase; MNP, magnetic nanoparticles; min, minutes.
Mentions: Corresponding Km values, indicating the affinity of the enzyme for the substrate and the maximum reaction rate (Vmax) of β-glucosidase are shown in Table 2 and Figure 5. The apparent Km value of the free enzyme was determined to be 2.23 mmol/L, and this was retained with β-Glu-MNP and PEG-β-Glu-MNP, which showed Km values of 2.27 mmol/L and 2.25 mmol/L, respectively. After conjugation, β-Glu-MNP and PEG-β-Glu-MNP showed maximum reaction rates of 23.7 μmol per minute per mg and 21.2 μmol per minute per mg, respectively, which were, respectively, about 73.0% and 65.4% that of the free enzyme (32.4 μmol per minute per mg). In our previous study,14 conjugated β-glucosidase showed maximum enzyme activity of 1.17 U/mg iron (44.1 µg enzyme/mg Fe) with an optimized feed ratio of β-glucosidase and MNP (1.45 mg protein/mg Fe). After PEGylation of β-Glu-MNP, the enzyme activity of the immobilized β-glucosidase decreased slightly to 1.05 U/mg Fe.

Bottom Line: The results showed that the multidomain structure and magnetization properties of these nanoparticles were conserved well throughout the synthesis steps, with an expected diameter increase and zeta potential shifts.Both magnetophoretic mobility analysis and pharmacokinetics showed improved in vitro/in vivo stability of PEG-β-Glu-MNP compared with β-Glu-MNP.In vivo magnetic targeting of PEG-β-Glu-MNP was confirmed by magnetic resonance imaging and electron spin resonance analysis in a mouse model of subcutaneous 9L-glioma.

View Article: PubMed Central - PubMed

Affiliation: Department of Urology, Hubei Hospital of Traditional Chinese Medicine, Hubei University of Chinese Medicine, Wuhan, People's Republic of China.

ABSTRACT
The stability of enzyme-conjugated magnetic iron oxide nanoparticles in plasma is of great importance for in vivo delivery of the conjugated enzyme. In this study, β-glucosidase was conjugated on aminated magnetic iron oxide nanoparticles using the glutaraldehyde method (β-Glu-MNP), and further PEGylated via N-hydroxysuccinimide chemistry. The PEG-modified, β-glucosidase-immobilized magnetic iron oxide nanoparticles (PEG-β-Glu-MNPs) were characterized by hydrodynamic diameter distribution, zeta potential, Fourier transform infrared spectroscopy, transmission electron microscopy, and a superconducting quantum interference device. The results showed that the multidomain structure and magnetization properties of these nanoparticles were conserved well throughout the synthesis steps, with an expected diameter increase and zeta potential shifts. The Michaelis constant was calculated to evaluate the activity of conjugated β-glucosidase on the magnetic iron oxide nanoparticles, indicating 73.0% and 65.4% of enzyme activity remaining for β-Glu-MNP and PEG-β-Glu-MNP, respectively. Both magnetophoretic mobility analysis and pharmacokinetics showed improved in vitro/in vivo stability of PEG-β-Glu-MNP compared with β-Glu-MNP. In vivo magnetic targeting of PEG-β-Glu-MNP was confirmed by magnetic resonance imaging and electron spin resonance analysis in a mouse model of subcutaneous 9L-glioma. Satisfactory accumulation of PEG-β-Glu-MNP in tumor tissue was successfully achieved, with an iron content of 627±45 nmol Fe/g tissue and β-glucosidase activity of 32.2±8.0 mU/g tissue.

Show MeSH
Related in: MedlinePlus