Toward Rapid and Automated Immunoassays: Using a Localized Electrochemical pH Modulation Platform to Perform a...

Area of Science:

• Electrochemistry
• Biosensors
• Analytical Chemistry

Background:

• Precise control of localized pH microenvironments is crucial for advanced biochemical assays.
• Existing methods for pH modulation can be complex and time-consuming.
• Development of rapid, sensitive diagnostic tools is essential for timely medical intervention.

Purpose of the Study:

• To develop an electrochemical platform for on-demand generation and control of localized pH microenvironments.
• To demonstrate the platform's capability in simplifying and accelerating immunoassays.
• To validate the platform for measuring clinically relevant biomarkers such as C-reactive protein (CRP).

Main Methods:

• Utilized an iridium oxide pH sensor with a closed-loop control algorithm.
• Employed solution-borne quinones and galvanostatic excitation on an indium tin oxide (ITO) electrode.
• Integrated pH modulation with a pH-sensitive fluorescence dye for a single-step immunoassay.

Main Results:

• Achieved controlled pH modulation rates up to 2 pH/s with high repeatability (±0.004).
• Maintained stable pH microenvironments for over 2 hours within ±0.0012 pH.
• Successfully demonstrated a single-step immunoassay for CRP measurement in 1 hour without washing steps.

Conclusions:

• The developed electrochemical platform offers precise and stable control of localized pH.
• The platform enables a simplified, rapid, single-step immunoassay suitable for point-of-care applications.
• This technology has the potential to reduce diagnostic errors and hands-on time for end-users.