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Charge binding of rhodamine derivative to OH− stabilized nanomaghemite: Universal nanocarrier for construction of magnetofluorescent biosensors

Paper ID Volume ID Publish Year Pages File Format Full-Text
693 60 2012 9 PDF Available
Title
Charge binding of rhodamine derivative to OH− stabilized nanomaghemite: Universal nanocarrier for construction of magnetofluorescent biosensors
Abstract

Superparamagnetic nanoparticles (20–40 nm) of maghemite, γ-Fe2O3, with well-defined stoichiometric structure, are synthesized by the borohydride reduction of ferric chloride at an elevated temperature (100 °C) followed by thermal treatment of the reaction product. Prepared maghemite nanoparticles reveal excellent colloidal stability for a long time without the necessity for any additional surface modification. These colloidal features are due to surface stabilizing OH– groups, which act as charge barriers preventing a particle aggregation and enabling a reversible binding of various oppositely charged organic substances. Such binding with rhodamine B isothiocyanate results in the fluorescent magnetic nanocarrier providing, at the same time, a spacer arm for covalent immobilization of other biosubstances including enzymes. In this work, we exploit this general applicability of the developed nanocarrier for covalent immobilization of glucose oxidase. This is the first reported example of magnetically drivable fluorescent nanocatalyst. The immobilized enzyme creates a 3–5 nm thick layer on the nanoparticle surface as proved by high-resolution transmission electron microscopy. This layer corresponds to 10 enzyme molecules, which are bound to the nanoparticle surface as found by the fluorimetric determination of flavin adenine dinucleotide. The developed magnetic fluorescent nanocatalyst, showing a rate constant of 32.7 s–1 toward glucose oxidation, can be used as a biosensor in various biochemical, biotechnological, and food chemistry applications. The presence of the nanocatalyst can be simply monitored by its fluorescence; moreover, it can be easily separated from the solution by an external magnetic field and repeatedly used without a loss of catalytic efficiency.

Keywords
Maghemite nanoparticles; Rhodamine isothiocyanate; Glucose oxidase nanocatalyst; Biosensor; OH− groups
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Charge binding of rhodamine derivative to OH− stabilized nanomaghemite: Universal nanocarrier for construction of magnetofluorescent biosensors
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Publisher
Database: Elsevier - ScienceDirect
Journal: Acta Biomaterialia - Volume 8, Issue 6, July 2012, Pages 2068–2076
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us