Ultrasensitive Enzyme-free Biosensor by Coupling Cyclodextrin Functionalized Au Nanoparticles and High-Performance...

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Point-of-Care Diagnostics

Background:

• Microfluidic paper-based analytical devices (μPADs) offer a low-cost, portable platform for diagnostics.
• Enzyme-free detection methods are desirable for simplifying diagnostic assays.
• Sensitive detection of tumor markers like CEA and PSA is crucial for early cancer diagnosis.

Purpose of the Study:

• To develop an enzyme-free μPAD for the simultaneous detection of two key tumor markers: carcinoembryonic antigen (CEA) and prostate-specific antigen (PSA).
• To create a novel sensor substrate utilizing gold nanoparticle-modified paper working electrodes (Au-PWE) and cyclodextrin-functionalized gold nanoparticles (CD@AuNPs) as enzyme mimics.
• To demonstrate the clinical applicability of the developed μPAD for sensitive and reliable point-of-care testing.

Main Methods:

• Fabrication of a gold nanoparticle (AuNP)-modified paper working electrode (Au-PWE) as the sensor substrate.
• Preparation of cyclodextrin-functionalized AuNPs (CD@AuNPs) acting as dual mimicking enzymes.
• Development of a sandwich immunoreaction for CEA detection involving CD@AuNPs and a cascade catalysis reaction.
• Implementation of a peptide cleavage strategy for PSA detection, releasing CD@AuNPs to alter electrochemical signals.

Main Results:

• The developed enzyme-free μPAD successfully detected both CEA and PSA with high sensitivity.
• The device exhibited wide linear detection ranges and low limits of detection for both tumor markers.
• The electrochemical signals were effectively modulated by the presence of CEA and PSA through distinct mechanisms.

Conclusions:

• The enzyme-free μPAD represents a promising platform for sensitive and simultaneous detection of multiple tumor markers.
• This technology holds significant potential for point-of-care testing, particularly in resource-limited settings.
• The novel use of CD@AuNPs as enzyme mimics offers a versatile approach for electrochemical biosensing.