Highly sensitive, label-free ATP detection using a small molecule–metal-based ensemble with a ratiometric absorption and fluorescence light-up approach

Abstract

Adenosine triphosphate (ATP) plays a vital role as a signalling molecule in numerous physiological functions, and imbalances in ATP levels are associated with various diseases. As a result, considerable attention has been directed toward its detection. Herein, a new small molecule–metal-based ensemble is developed for ATP detection in pure water, utilizing the inexpensive commercially available probe 1′-hydroxy-2′-acetonaphthone (1H2AN) and Cu²⁺ ion. In this system, the Cu²⁺ ion quenches the fluorescence of 1H2AN and induces a remarkable red shift (∼24 nm) in the absorption peak. Upon ATP addition, the 1H2AN-Cu²⁺ ensemble exhibits ratiometric changes in absorption and fluorescence turn-on response, attributed to the strong coordination ability between ATP and Cu²⁺ ion. This sensor system demonstrates an impressive detection limit as low as 0.36 μM. This system is simple yet highly sensitive, operating in water with dual-wavelength responses. Additionally, employing the commercial probe offers advantages over synthetic alternatives, saving both time and resources. The fluorescence off–on switching of 1H2AN with Cu²⁺ and ATP facilitated the construction of an IMPLICATION logic gate. Importantly, the 1H2AN-Cu²⁺ ensemble was effective in quantifying ATP in 0.15 M NaCl (mimicking physiological conditions), and in diluted human urine, demonstrating its promise for real bioanalytical applications. The current study highlights the potential of small molecule–metal-based complexes for ATP sensing and future biosensing platforms.