Label-Free Liquid Crystal Aptamer Sensors Based on Single-Stranded Nucleic Acid π-Structures for Detecting cTnI

Area of Science:

• Biomedical Engineering
• Nanotechnology
• Analytical Chemistry

Background:

• Cardiac troponin I (cTnI) is a critical biomarker for diagnosing myocardial injury and acute myocardial infarction.
• Rapid and accurate detection of cTnI is essential for timely cardiovascular disease management.
• Existing detection methods may have limitations in terms of speed, cost, or complexity.

Purpose of the Study:

• To develop a novel label-free liquid crystal aptasensor for the quantitative detection of cardiac troponin I (cTnI).
• To utilize nucleic acid molecular hybridization and aptamer-specific binding for enhanced sensor performance.
• To provide a sensitive, specific, and cost-effective diagnostic tool for myocardial injury.

Main Methods:

• Development of a liquid crystal aptasensor based on single-stranded nucleic acid π-structures.
• Immobilization of complementary oligonucleotide chains (CP1 and CP2) onto a sensor substrate.
• Formation of a π-structure by the aptamer with CP1 and CP2 for target capture.
• Detection mechanism based on the competitive binding of cTnI with the aptamer, disrupting the π-structure and altering liquid crystal alignment.

Main Results:

• The sensor demonstrated a linear correlation between brightness area coverage and cTnI concentration (0.01–25 ng/mL).
• Achieved a highly sensitive detection limit of 5.16 pg/mL for cTnI.
• Successfully detected cTnI in serum samples with good specificity.

Conclusions:

• The developed label-free liquid crystal aptasensor is a promising tool for the rapid, sensitive, and quantitative detection of cTnI.
• This method offers a simple, low-cost, and effective approach for early diagnosis of myocardial injury.
• The sensor's performance in serum samples highlights its potential for clinical application.