SERS-nanoenzyme sensor based on Au@ZIF-8 nanoparticles for homocysteine detection in the serum of colorectal cancer patients

Abstract

In this study, we developed a surface-enhanced Raman scattering (SERS) platform for the ultrasensitive detection of homocysteine (Hcy) in colorectal cancer (CRC) patients, based on the high catalytic activity of Au@ZIF-8. Au@ZIF-8 exhibits outstanding nanocatalytic performance and strong SERS enhancement, oxidizing 3,3′,5,5′-tetramethylbenzidine (TMB) to oxidized TMB (ox-TMB), thereby generating a significant SERS signal. In the presence of Hcy, the oxidation of TMB is inhibited, leading to a weakened SERS signal. Across a concentration range of 10⁻¹² to 10⁻⁵ mol L⁻¹, the SERS intensity was observed as a function of the logarithmic Hcy concentration and SERS intensity. The limit of detection (LOD) was 7.6 × 10⁻¹³ mol L⁻¹, consistent with that obtained by ELISA. This method provides a novel and effective approach for Hcy detection and demonstrates significant potential for the early diagnosis of CRC.