Target-Induced Shielding Layer at the Dual-Affinity Probe Interface for Rapid Colorimetric Detection of Cardiac...

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Analytical Chemistry

Background:

• Cardiac troponin I (cTnI) is a critical biomarker for acute myocardial infarction (AMI).
• Current cTnI detection methods are often slow, complex, and require expensive equipment, limiting point-of-care applications.
• There is a need for rapid, sensitive, and cost-effective cTnI assays.

Purpose of the Study:

• To develop a novel, rapid, and sensitive colorimetric assay for cardiac troponin I (cTnI) detection.
• To utilize a nanoparticle shielding layer and enzyme interaction for enhanced detection sensitivity.
• To provide a potential solution for point-of-care testing of AMI.

Main Methods:

• A dual-affinity silver nanoparticle (AgNP) probe functionalized with aptamer (Apt) and antibody (Ab) was designed.
• The probe's interfacial interaction with urease was modulated by the presence or absence of cTnI.
• Colorimetric detection was achieved through enzyme activity, with results analyzed using microscale thermophoresis (MST).

Main Results:

• The assay detected cTnI with a limit of detection of 0.088 ng/mL.
• Visual detection was achieved in under 15 minutes.
• The assay demonstrated high sensitivity and specificity in complex biological matrices.
• MST confirmed target-induced shielding of enzyme-particle interaction.

Conclusions:

• A rapid, sensitive, and solution-phase colorimetric assay for cTnI detection was successfully developed.
• The assay overcomes limitations of traditional methods like ELISA by eliminating immobilization and blocking steps.
• This approach represents a significant advancement for point-of-care diagnostics of acute myocardial infarction.