A new di-recognition and di-functional nanosurface aptamer molecularly imprinted polymer probe for trace glyphosate...

A new di-recognition nitrogen-doped carbon dot nanosurface aptamer molecularly imprinted polymer (CD_NAg@MIPApt) nanocatalytic di-functional probe was prepared by microwave irradiation. The probe was utilized nitrogen-doped silver carbon dots (CD_NAg) as the matrix, glyphosate (Gly) as the template molecule, α-methyl acrylate as the monomer, ethylene glycol dimethacrylate as the cross-linker, and aptamer as the biorecognition element. It could not only recognize Gly but also exhibits catalytic amplification function. It was found that CD_NAg@MIPApt catalyzed the redox reaction of polyethylene glycol 400 (PEG400)-AgNO₃ to generate silver nanoparticles (AgNPs). The AgNPs indicator component exhibit the effects of surface-enhanced Raman scattering (SERS), resonance Rayleigh scattering (RRS) and surface plasmon resonance absorption (Abs). In the presence of Gly, it binds to the surface imprinted site of CD_NAg@MIPApt, to reduce AgNPs generation due to the catalytic activity of CD_NAg@MIPApt decreasing. Thus, the SERS/RRS/Abs signal values decreased linearly. The linear ranges of SERS/RRS/Abs assay were 0.1-2.5 nM, 0.25-2.75 nM and 0.5-5 nM respectively. The detection limits were 0.034 nM, 0.071 nM and 0.18 nM Gly.