A new peptide-mediated COF nanocatalytic amplification SERS quantitative assay for ultratrace Cu2+

Peptides are an important recognition element for small molecules and have been used in the field of biological analysis. However, it has been rarely reported that a novel method combining peptides as recognition elements with covalent organic framework (COF) as catalytic amplification signal to construct highly sensitive and selective three-mode molecular spectroscopy. In this paper, high catalytic and stable three COFs were prepared, and the catalysis of the new indicator nanoreaction of HAuCl4-sodiumformate (Fo) was studied by molecular spectral slope procedure. The produced gold nanoparticles (AuNPs) exhibit a strong resonance Rayleigh scattering (RRS) peak at 370 nm and surface plasmon resonance absorption (Abs) peak at 540 nm. In the presence of molecular probes, a strongest surface-enhanced Raman scattering (SERS) peak was generated at 1617 cm−1. Combining the COFTpBD amplification indicator reaction with specific peptide (PT) reaction of Cu2+, a novel, sensitive and selective SERS/RRS/Abs assay platform was established, with a SERS linear range of 0.005–0.115 nmol/L Cu2+. In addition, the two working curves of lg[Cu2+] vs SERS and [Cu2+] vs SERS intensity, and the nanocatalytic mechanism were discussed.