Label-free aptamer-based electrochemical impedance biosensor for 17β-estradiol

Area of Science:

• Electrochemistry
• Biosensor Technology
• Analytical Chemistry

Background:

• 17β-estradiol is a key endocrine-disrupting chemical.
• Accurate detection of 17β-estradiol is crucial for environmental and health monitoring.
• Existing detection methods can be complex or lack sensitivity.

Purpose of the Study:

• To develop a novel aptamer-based label-free electrochemical impedance spectroscopy (EIS) biosensor.
• To detect and quantify 17β-estradiol with high sensitivity and selectivity.
• To validate the biosensor's performance in a real-world sample matrix (human urine).

Main Methods:

• Immobilization of aptamers on a gold electrode via Au-S interaction.
• Label-free electrochemical impedance spectroscopy (EIS) for signal transduction.
• Formation of an estradiol/aptamer complex on the electrode surface upon analyte binding.
• Linear regression analysis to correlate resistance changes with 17β-estradiol concentration.

Main Results:

• The biosensor exhibited a significant increase in interfacial electron transfer resistance upon 17β-estradiol binding.
• A linear response was observed for 17β-estradiol concentrations ranging from 1.0 × 10⁻⁸ to 1.0 × 10⁻¹¹ mol L⁻¹.
• A low detection limit of 2.0 × 10⁻¹² mol L⁻¹ was achieved.
• The biosensor demonstrated high selectivity and good stability.
• Satisfactory results were obtained when applied to detect 17β-estradiol in human urine.

Conclusions:

• A novel and effective aptamer-based label-free EIS biosensor for 17β-estradiol detection has been successfully fabricated.
• The biosensor offers a sensitive, selective, and stable platform for 17β-estradiol quantification.
• The developed biosensor shows potential for practical applications in monitoring 17β-estradiol levels in biological samples like human urine.