Gold nanoparticle aptasensor synergizing colorimetric and Tyndall effect signals for ultrasensitive ATP detection

Conventional ATP detection methods (e.g., fluorescence and electrochemistry) face significant sensitivity constraints, while colorimetric approaches-despite offering visual simplicity-remain inadequate for clinical applications due to limited detection capabilities. To address this dual challenge, we developed a dual-mode nanosensor leveraging gold nanoparticles (AuNPs), which synergistically integrates colorimetric signals (aggregation-induced red-to-blue shift) and Tyndall effect scattering for ultra-sensitive ATP quantification. The core mechanism exploits aptamer-mediated recognition: ATP binding triggers the release of cDNA from dsDNA complexes, enabling cDNA adsorption onto AuNPs to inhibit salt-induced aggregation. The proposed sensor demonstrates three major improvements: 125-fold sensitivity enhancement versus conventional colorimetry, record-low detection limits of 0.17 µM (colorimetric) and 1.28 nM (Tyndall effect), and a broad linear detection range (0.25-750 µM, R² > 0.91) with 5 min visual readout. Validation in complex yogurt matrices demonstrated exceptional robustness, yielding 96.1-110.2% recovery and precision (RSD < 10%). This cost-effective, minimal-equipment platform (requiring only a laser pointer for Tyndall readout) shows potential to bridge point-of-care screening with laboratory-grade quantification, highlighting its promising applicability for clinical diagnostics and environmental monitoring.