Facile and sensitive method for detecting cardiac markers using ubiquitous pH meters

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Nanotechnology

Background:

• Troponin I is a critical cardiac biomarker for diagnosing myocardial infarction.
• Existing detection methods can be complex, time-consuming, or require specialized equipment.
• There is a need for sensitive, rapid, and user-friendly troponin I detection assays.

Purpose of the Study:

• To develop a sensitive and easy method for detecting cardiac troponin I.
• To utilize magnetic nanoparticle clusters and pH meters for troponin I quantification.
• To achieve rapid detection suitable for potential point-of-care applications.

Main Methods:

• Synthesized monoclonal antibody-functionalized Fe3O4 magnetic nanoparticle clusters (MNCs) for troponin capture.
• Magnetically isolated MNC-troponin complexes from human serum.
• Conjugated complexes to polyclonal antibody-functionalized acetylcholinesterase (AchE) and measured pH changes upon acetylcholine hydrolysis using a pH meter.

Main Results:

• Achieved a detection sensitivity of 10 pg/mL for troponin I in human serum.
• The assay provided results within 10 minutes of the hydrolysis reaction.
• pH changes were visually detectable via a pH indicator strip's color change.

Conclusions:

• A sensitive, rapid, and easy magnetic immunoassay for troponin I detection was successfully developed.
• The method leverages magnetic separation and pH changes for signal generation.
• This assay shows promise for accessible cardiac marker detection.