A new COF@AuNC catalytic amplification-aptamer SERS quantitative analysis method for trace estradiol with nanoreaction of HAuCl4-sulfite

A new covalent organic framework loaded gold nanocluster (AuCOF) was prepared by solvothermal procedure, using 1,3,5-benzenetricarboxaldehydeand p-phenylenediamine and chloroauric acid as precursor. It was found that the AuCOF exhibits strong catalysis of sulfite reduction of HAuCl4 to form gold nanoparticles (AuNP) with surface enhanced Raman scattering (SERS) and resonance Rayleigh scattering (RRS) effects. The aptamer (Apt) of estradiol (E2) can be electrostatically adsorbed on the AuCOF surface to suppress its catalytic performance. While the AptE2 can selectively bind to target molecule E2 and desorb from the AuCOF surface to recover its catalysis. The SERS and RRS signals increased linearly with E2 concentration increasing due to produce more AuNP indicator. The highly sensitive SERS method shows good linearity with E2 concentration in the range of 0.333–5.33nmol/L, and the detection limit was 0.150 nmol/L E2. This SERS method has been used for the determination of E2 in actual samples. In addition, the nanocatalytic mechanism and SERS quantitative analysis formula were studied.