Multienzymatic-rotating biosensor for total cholesterol determination in a FIA system.

Area of Science:

• Analytical Chemistry
• Biotechnology
• Electrochemistry

Background:

• Cholesterol determination is crucial for cardiovascular health assessment.
• Existing methods may face limitations in speed, accuracy, or interference.
• Enzymatic biosensors offer a promising alternative for sensitive cholesterol detection.

Purpose of the Study:

• To fabricate and characterize an amperometric-rotating biosensor for enzymatic cholesterol determination.
• To optimize the biosensor for enhanced sensitivity, selectivity, and response time.
• To validate the biosensor's performance for total cholesterol measurement in a relevant concentration range.

Main Methods:

• Co-immobilization of cholesterol esterase (ChE), cholesterol oxidase (ChOx), and peroxidase (HRP) on a rotating disk.
• Utilized a glassy carbon electrode with a soluble-redox mediator (4-tert-butylcatechol, TBC).
• Incorporated a micro packed-column with immobilized ascorbate oxidase (AAOx) to eliminate ascorbic acid interference.

Main Results:

• The biosensor demonstrated a linear response for total cholesterol from 1.2µM to 1mM (r=0.999).
• Achieved a rapid response time of 2 minutes and a low detection limit of 11.9 nM.
• Exhibited good reproducibility with a standard error of less than 4% and a lifetime of up to 25 days.

Conclusions:

• The developed amperometric-rotating biosensor provides a sensitive, selective, and rapid method for total cholesterol determination.
• The integrated system effectively minimizes interference from ascorbic acid.
• This biosensor shows potential for clinical diagnostics and biochemical analysis.