Stimuli-Responsive Luminophore Drives Mechanism Switch for Highly Efficient Electrochemiluminescence Immunosensing

Area of Science:

• Electrochemistry
• Biotechnology
• Analytical Chemistry

Background:

• Electrochemiluminescence (ECL) immunoassays, widely used in diagnostics, face sensitivity limitations due to their reaction mechanism.
• The 'remote' ECL pathway is hindered by slow coreactant oxidation and short-lived radicals, impacting [Ru(bpy)₃]²⁺ emission efficiency.

Purpose of the Study:

• To engineer a stimuli-responsive luminophore to overcome the limitations of traditional ECL immunoassays.
• To enhance the sensitivity and efficiency of ECL-based biosensors through a novel reaction mechanism.

Main Methods:

• Synthesis of a [Ru(bpy)₃]²⁺ derivative with a stimuli-responsive disulfide bond.
• Utilizing electrogenerated tri-n-propylamine (TPrA) radicals to cleave the disulfide bond and release Ru(II) labels.
• Employing ICP-MS, ECL microscopy, and finite element simulations for analysis.

Main Results:

• Demonstrated rapid disulfide bond cleavage and up to 613% signal enhancement.
• Developed an ECL immunoassay for SARS-CoV-2 Spike protein detection with a 40% lower detection limit and 2-fold increased sensitivity.
• Achieved a 72% reduction in TPrA consumption.

Conclusions:

• Stimuli-responsive luminophores represent a groundbreaking advancement for ECL labels.
• This approach promises substantial improvements in the sensitivity of commercial biosensors.
• The developed method offers a more efficient and sensitive platform for clinical diagnostics.