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@NH2-MIL-125(Ti) composites) and graphene modified glassy carbon electrode. The AuNPs supported amino-functionalized Ti-benzenedicarboxylate porous metal-organic frameworks (Au/NH2-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 AuS 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.