Oxytocin-Monolayer-Based Impedimetric Biosensor for Zinc and Copper Ions

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Neuroscience

Background:

• Zinc (Zn²⁺) and copper (Cu²⁺) are essential metal ions crucial for biological functions, with their serum ratio linked to various diseases.
• Oxytocin (OT), a neuropeptide, interacts with Zn²⁺ and Cu²⁺, suggesting its potential utility in metal ion sensing.

Purpose of the Study:

• To develop and characterize a novel impedimetric biosensor utilizing oxytocin (OT) immobilized on a glassy carbon electrode for detecting Zn²⁺ and Cu²⁺ ions.
• To assess the sensor's selectivity, sensitivity, and ability to determine the Zn/Cu ratio in biological samples, including patient sera.

Main Methods:

• Immobilization of oxytocin (OT) onto a glassy carbon electrode to create an impedimetric biosensor.
• Electrochemical impedance spectroscopy (EIS) was employed to detect Zn²⁺ and Cu²⁺ ions at physiological pH.
• Selective masking techniques were utilized for simultaneous determination of the Zn/Cu ratio.

Main Results:

• The OT-based biosensor demonstrated ultrasensitivity to Zn²⁺ and Cu²⁺ ions, showing distinct impedimetric responses due to metal-dependent conformational changes in OT.
• The sensor exhibited selectivity for Zn²⁺ and Cu²⁺ over other biologically relevant ions.
• The developed sensor successfully differentiated between healthy control and multiple sclerosis patient serum samples based on their Zn/Cu ratios, performing comparably to existing methods.

Conclusions:

• The OT-based impedimetric biosensor offers a sensitive and selective platform for determining the Zn/Cu ratio in biological fluids.
• This neuropeptide-derived sensor shows promise for applications in disease diagnosis, particularly for immunological and inflammatory disorders.
• The study highlights the potential of harnessing neuropeptides for developing advanced biosensors for biomedical research.