Cu-Trp nanoparticle mimetic enzyme-based colorimetric immunoassay for CA19-9 detection

Area of Science:

• Biochemistry
• Nanotechnology
• Analytical Chemistry

Background:

• Sensitive detection of Carbohydrate Antigen 19-9 (CA19-9) is crucial for cancer screening, monitoring treatment efficacy, and assessing prognosis.
• Existing methods for CA19-9 detection require improvement in sensitivity and accuracy for early cancer diagnosis.

Purpose of the Study:

• To develop a novel, highly sensitive colorimetric immunoassay for CA19-9 detection.
• To utilize copper-tryptophan (Cu-Trp) nanoparticles as a nanozyme for enhanced assay performance.

Main Methods:

• A sandwich-type colorimetric immunoassay was designed using Cu-Trp nanoparticles with ascorbic acid oxidase-like activity.
• Cu-Trp nanoparticles catalyze the oxidation of ascorbic acid, influencing a colorimetric reaction involving Fe(BPT)3.
• The assay measures changes in UV absorbance at 534 nm, correlating with CA19-9 concentration.

Main Results:

• The developed immunoassay demonstrated high sensitivity for CA19-9 detection.
• A linear correlation was established between UV absorbance and the logarithm of CA19-9 concentration (4–1000 U mL⁻¹).
• A low detection limit of 0.38 U mL⁻¹ was achieved under optimized conditions.

Conclusions:

• The Cu-Trp nanoparticle-based colorimetric immunoassay provides a sensitive and accurate method for CA19-9 detection.
• This analytical strategy shows significant potential for early cancer screening and monitoring of other tumor biomarkers.