An integrated microfluidic-based biosensor using a magnetically controlled MNPs-enzyme microreactor to determine...

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Biosensing Technology

Background:

• Accurate total cholesterol determination is crucial for cardiovascular disease risk assessment.
• Existing methods may lack the speed, sensitivity, or integration required for point-of-care diagnostics.
• Microfluidic platforms offer miniaturization and enhanced reaction control for biosensing applications.

Purpose of the Study:

• To develop and validate a microfluidic-based biosensor for rapid and sensitive determination of total cholesterol in serum.
• To integrate a magnetically retained enzyme microreactor (MREµR) with remote fluorometric detection.
• To assess the performance characteristics and clinical applicability of the developed biosensor.

Main Methods:

• Enzymatic hydrolysis and oxidation of cholesterol using cholesterol esterase (ChE) and cholesterol oxidase (ChOx) immobilized on magnetic nanoparticles (MNPs).
• Microfluidic chip design integrating a MREµR with a bifurcated fiber-optic bundle (BFOB) for spectrofluorometric detection.
• Monitoring fluorescence decrease via naphtofluorescein (NF) oxidation coupled with H2O2 production.

Main Results:

• The biosensor demonstrated a wide dynamic range (0.005-10 mmol L⁻¹) with a low detection limit (1.1 µmol L⁻¹).
• High precision (RSD 1.3-2.1%) and a sampling frequency of 30 h⁻¹ were achieved.
• Serum sample analysis showed excellent recovery rates (94.8-102%), correlating well with established methods.

Conclusions:

• The developed microfluidic biosensor offers a sensitive, precise, and rapid method for total cholesterol determination in serum.
• The integration of MREµR and BFOB provides an efficient platform for enzymatic biosensing.
• This technology holds potential for improved cardiovascular risk assessment and clinical diagnostics.