Target-Induced Dual-Wing Photocurrent Response Based on Au@CdSe@Au Nanoparticles for Ultrasensitive Detection of Cholesterol

Cholesterol occupies a pivotal role in human physiological functions and reproductive processes. Elevated cholesterol levels can predispose individuals to heart disease and stroke, whereas depleted levels weaken the immune system. Therefore, it is crucial to develop cholesterol detection methods with a sufficiently wide linear detection range. In this study, we harnessed the dual-wing photocurrent response triggered by cholesterol, in tandem with the host–guest recognition capability of β-cyclodextrin, to achieve a sufficiently wide linear detection range for cholesterol detection. We synthesized an excellent performance Au@CdSe@Au optoelectronic material, which complements the energy levels of methylene blue (MB). Afterward, mercapto cyclodextrin and MB were modified on Au@CdSe@Au nanoparticles, which converts anode photocurrent into cathode photocurrent. When cholesterol is present, methylene blue in cyclodextrin can be replaced. As the concentration of cholesterol continues to increase, the sensing platform exhibits a unique photocurrent transition process. During this process, the photocurrent gradually shifts from a cathode photocurrent to an anodic photocurrent. This transition not only demonstrates the high sensitivity of the sensing platform to cholesterol concentration but also endows the platform with a wider detection range. The linear range of the photoelectrochemical analysis (PEC) sensor for the detection of cholesterol is 10–800 nM, and the detection limit is 2.3 nM. Such wide-range detection capability enables the sensing platform to accurately capture changes in cholesterol concentration at different levels, providing more comprehensive and accurate data support for clinical detection. Therefore, this sensing platform holds broad application prospects and significant practical value in the field of cholesterol detection.