Development of Dopamine Sensor Using Silver Nanoparticles and PEG-Functionalized Tapered Optical Fiber Structure

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Nanotechnology

Background:

• Dopamine (DA) is a vital neurotransmitter and hormone.
• Accurate detection of DA is crucial for diagnosing neurological and physiological conditions.
• Existing DA detection methods often lack sensitivity, selectivity, or portability.

Purpose of the Study:

• To develop a highly sensitive and selective optical fiber sensor for dopamine detection.
• To leverage localized surface plasmon resonance (LSPR) for enhanced sensing capabilities.
• To validate the sensor's performance for potential routine diagnostic applications.

Main Methods:

• Fabrication of a taper fiber probe.
• Immobilization of silver nanoparticles (AgNPs) onto the probe.
• Functionalization of the probe with Polyethylene glycol (PEG) for selectivity.
• Characterization using UV-visible spectrophotometry, TEM, EDS, and SEM.
• Performance evaluation including sensitivity, detection limit, and dynamic range.

Main Results:

• The developed sensor demonstrated high selectivity for dopamine, even in the presence of interfering substances like ascorbic acid.
• Characterization confirmed the uniform coating of AgNPs on the sensing probe.
• A linear calibration curve was observed within the range of 10 nM to 1 μM.
• The sensor achieved a low detection limit of 0.058 μM and a wide dynamic range (10 nM–100 μM).

Conclusions:

• The LSPR-based optical fiber sensor offers improved sensitivity, selectivity, and detection limits for dopamine.
• The PEG functionalization effectively enhances sensor selectivity.
• The validated sensor shows significant potential for routine dopamine diagnosis.