Target Recognition of <sup>•</sup> OH via Customized <i>o</i> -Hydroxyphenyl Pillar[5]arenes-Functionalized Gold Photochemical Sensors in Cells
Jin Wang, Zhan Shu, Jimei Chen, Jiali Bei, Yu-Cheng Wu, Tingting Chen, Yang Wang, Yukou Du, Yong Yao
Abstract
The hydroxyl radical ( • OH), one of the most reactive oxygen species (ROS), exhibits unparalleled oxidative capacity, inducing direct damage to proteins, lipids, and DNA, thereby triggering cellular dysfunction and death. Herein, we develop a triple-signal-amplified biosensor based on N -(2-hydroxyphenyl)acetamido- and sulfhydryl-modified pillar[5]arene (HE/SH-P5)-functionalized gold nanoparticles (Au@HE/SH-P5 NPs) for the highly specific detection of • OH under visible light irradiation. HE/SH-P5 confers specificity and enables signal amplification through the reaction of its functional groups with • OH. Notably, the host molecule concentrates hydroxyl radicals within its cavity via host–guest complexation, while the localized surface plasmon resonance of gold nanoparticles synergistically enhances photoelectrochemical (PEC) signal amplification. The sensor achieves pH-dependent ultralow detection limits (0.3 μM at pH 2; 0.1 μM at pH 7.4, S/N = 3) and a broad linear range (1–250 μM at pH 2; 0.3–100 μM at pH 7.4). Significantly, the PEC platform demonstrates exceptional performance in monitoring • OH within HeLa cells, underscoring its considerable potential for fundamental ROS research, pathophysiological studies, and clinical diagnostics.