Highly Reusable Electrochemical Immunosensor for Ultrasensitive Protein Detection

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Nanotechnology

Background:

• Ultrasensitive protein biomarker detection is crucial for clinical diagnostics and health monitoring.
• Existing methods like ELISA and electrochemical sensing have limitations including long incubation times, high costs, and waste generation due to single-use electrodes.

Purpose of the Study:

• To develop a reusable electrochemical immunosensor for ultrasensitive protein biomarker detection.
• To demonstrate the sensor's efficacy in detecting a specific biomarker (CXCL9) in human urine.
• To adapt the sensor for use with a portable diagnostic device.

Main Methods:

• Fabrication of a reusable electrochemical immunosensor utilizing magnetic nanoparticles (MNPs) and dually labeled gold nanoparticles (AuNPs).
• Detection of C-X-C motif chemokine ligand 9 (CXCL9) in human urine samples.
• Adaptation of the immunosensor onto a smartphone-based diagnostic device.

Main Results:

• The developed immunosensor detected CXCL9 at concentrations as low as 27 pg/mL within approximately 1 hour.
• The smartphone-based device achieved a lower limit of detection of 65 pg/mL for CXCL9.
• The sensing electrodes demonstrated reusability for over 100 measurements with minimal performance degradation.

Conclusions:

• The reusable electrochemical immunosensor offers a cost-effective and environmentally friendly alternative for ultrasensitive protein detection.
• The platform shows potential for rapid, point-of-care diagnostics, particularly for monitoring biomarkers like CXCL9.
• The integration with a smartphone device enhances the accessibility and portability of the diagnostic technology.