Three-dimensional molecularly imprinted electrochemical sensor based on Au NPs@Ti-based metal-organic frameworks for ultra-trace detection of bovine serum albumin

A novel three-dimensional molecularly imprinted electrochemical sensor (MIECS) was fabricated for ultra-trace detection of biomacromolecules bovine serum albumin (BSA), which was based on 3D porous electrocatalytic framework materials (AuNPs@NH 2 -MIL-125(Ti) composites) and graphene modified glassy carbon electrode. The AuNPs supported amino-functionalized Ti-benzenedicarboxylate porous metal-organic frameworks (Au/NH 2 -MIL-125(Ti)) was prepared by a simple and rapid ultrasonic method. The stable proteins molecularly imprinted polymers (MIPs) films were fabricated by electropolymerization using l -cysteine (L-Cys) as functional monomers and BSA as templates. The monomer L-Cys interact with AuNPs by Au S bonds and interact with BSA by hydrogen bonding and electrostatic interaction , which was characterized with UV–vis spectra. The morphology of the MIP modified electrode was characterized by scanning electron microscopy, transmission electron microscopy and atomic force microscope. Under the optimal conditions, the 3D MIECS exhibited a wide linear range of 10 −18  g mL −1 to 10 −12  g mL −1 of BSA and an extremely low detection limit of 4.147 × 10 −19  g mL −1 . The 3D MIECS has been applied to the assay of BSA in liquid milk samples with satisfying results.