“…Acetylcholine (Ach), a neurotransmitter, intimately connects to the neural signal transmission, and a deficiency of Ach concentration production induces AD progression [8]. To detect these AD biomarkers, a variety of methods has been employed, from conventional methods, such as positron emission tomography (PET) [16], magnetic Biosensors 2023, 13, 987 2 of 18 resonance imaging (MRI) [17], and near-infrared fluorescence (NIRF) [18], to modern methods, such as electrochemistry [19,20], fluorescence [21], and colorimetry [22,23]. Each of these provides a particular insight into AD and has advantages and disadvantages.…”