Deciphering the Interface between Two-Dimensional Aluminum Quasicrystals and Norepinephrine Neurotransmitter

Norepinephrine (NE) serves as a vital neurotransmitter, regulating various physiological and cognitive processes in the central nervous system. NE detection is crucial for improving diagnostic and therapeutic monitoring. The current study elucidates the molecular interactions of NE with a two-dimensional multielement aluminum quasicrystal (2D-Al₇₀Co₁₀Fe₅Ni₁₀Cu₅ (2D-Al QC)) through vibrational spectroscopy and theoretical simulations including geometry optimization, charge transfer dynamics, and bond length variations. The interaction dynamics are monitored in real-time at the atomic scale by in situ liquid cell transmission electron microscopy (LCTEM). The results confirm the binding of the -OH group of NE molecules with the aluminum atoms of the 2D-Al QC by Al-O bonding. Based on this binding mechanism, an electrochemical sensor is developed using the 2D-Al QC, for ultrasensitive and selective detection of NE. The sensor exhibits two distinct linear detection ranges: a higher range from 1 nM to 1 μM, and a lower range from 1 pM to 500 pM. The sensor achieves ultralow detection limits of 0.42 ± 0.02 nM and 0.17 ± 0.04 pM, with corresponding quantification limits of 1.28 ± 0.02 nM and 0.5 ± 0.04 pM. The sensor demonstrates outstanding selectivity against potential interferents, excellent reproducibility across seven electrodes with minimal variation of 3%, and sustained performance over 90 days with a negligible deviation of 4.6%. This work highlights the potential of 2D-Al QC-based electrochemical sensors as a robust, scalable platform for neurotransmitter detection, paving the way for enhanced point-of-care diagnostics and neurochemical monitoring.