Oxidase-functionalized Fe(3)O(4) nanoparticles for fluorescence sensing of specific substrate

Area of Science:

• Nanotechnology
• Biochemistry
• Analytical Chemistry

Background:

• Enzyme-functionalized nanoparticles offer unique platforms for biosensing applications.
• Developing sensitive and reusable detection systems is crucial for clinical diagnostics.

Purpose of the Study:

• To develop a reusable, single-step detection system for specific substrates using oxidase-functionalized Fe(3)O(4) nanoparticles (NPs).
• To quantify specific substrates via H(2)O(2)-mediated oxidation of amplex ultrared (AU) using a composite of PDDA-modified Fe(3)O(4) NPs and oxidase.

Main Methods:

• Preparation of oxidase-functionalized Fe(3)O(4) NPs as a bienzyme system.
• Modification of Fe(3)O(4) NPs with poly(diallyldimethylammonium chloride) (PDDA).
• Formation of a composite with PDDA-modified Fe(3)O(4) NPs and oxidase for substrate quantification.
• Monitoring fluorescence intensity of oxidized AU at 587 nm.

Main Results:

• The catalytic activity of Fe(3)O(4) NPs with AU remained stable after PDDA modification.
• Minimum detectable concentrations were 3 μM for glucose, 2 μM for galactose, and 20 μM for choline.
• The system demonstrated applicability for glucose detection in blood samples.

Conclusions:

• A reusable, single-step biosensing system based on oxidase-functionalized Fe(3)O(4) NPs was successfully developed.
• The proposed method allows for sensitive quantification of glucose, galactose, and choline.
• The system shows potential for practical applications in biological sample analysis.