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

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 (similar to 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 mu M. 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.