A dual-mode aptasensor based on rolling circle amplification enriched G-quadruplex for highly sensitive IFN-γ...

Area of Science:

• Biomedical Engineering
• Analytical Chemistry
• Molecular Diagnostics

Background:

• Aptasensors offer high sensitivity and rapid detection but lack inherent reliability verification.
• Single-mode aptasensors present challenges in validating detection accuracy in real-time.
• Developing cross-validated detection methods is crucial for enhancing biosensor reliability.

Purpose of the Study:

• To design and develop a colorimetric and fluorescent dual-mode aptasensor for highly reliable detection of interferon-gamma (IFN-γ).
• To engineer G-quadruplex assembly and rolling circle amplification for enhanced sensitivity and accuracy.
• To create a versatile platform for multimode biosensing applications.

Main Methods:

• Modification of magnetic beads with anti-IFN-γ aptamers and complement sequences (cDNA).
• IFN-γ triggered release of cDNAs, followed by magnetic separation.
• Rolling circle amplification (RCA) of released cDNAs to generate G-quadruplexes.
• G-quadruplex-hemin complex for colorimetric detection (TMB substrate) and G-quadruplex-Thioflavin T for fluorescent detection.

Main Results:

• The dual-mode aptasensor achieved a linear detection range of 1-10000 pM (colorimetric) and 0.1-10000 pM (fluorescent).
• Detection limits were as low as 0.406 pM (colorimetric) and 0.037 pM (fluorescent).
• The aptasensor demonstrated satisfactory performance in detecting IFN-γ in human serum samples with good recovery rates.

Conclusions:

• The developed dual-mode aptasensor effectively integrates aptamer binding, G-quadruplex formation, and RCA for reliable IFN-γ detection.
• This strategy provides a robust tool for IFN-γ testing and advances the development of multimode sensing platforms.
• The dual-mode approach enhances detection reliability through built-in cross-validation capabilities.