Integrating photothermal effect and peroxidase-like activity of inorganic/organic nanocomposite to advance photothermometric cholesterol sensing performance

Photothermometric sensors with a portable thermometer as signal reader have been extensively used in the field of point-of-care testing (POCT) due to their simplicity, low cost and high practicability. However, a long-standing challenge of low sensitivity has greatly limited the development and application, especially for most nanozyme-based sensing systems. We herein demonstrated an enhanced photothermometric cholesterol (CHOL) sensor by integrating the photothermal effect and peroxidase-like activity of inorganic/organic nanocomposite. In this design, CHOL selectively binds to the PB@PDA@β-CD inorganic/organic nanoprobe, which not only effectively inhibits the photothermal response of PB@PDA@β-CD, but also suppresses the peroxidase-like activity of PB@PDA@β-CD and resulting in a significant decrease on the photothermal response of nanozymes catalyzed oxTMB. Therefore, we have developed a new strategy for signal-amplified photothermal detection CHOL with dual-signaling transduction channels. The limit of detection (LOD) was 0.15 μM (S/N=3), which can meet the demand for CHOL detection in serum samples, and has potential application in early diagnosis and quantitative analysis of disease.