Biomimetic anti-fouling interface engineering based on thorn-vine-like structure for electrochemical sensing

Electrochemical sensing interfaces face an enormous obstacle posed by the non-specific adsorption in complex matrixes. This will decrease the current and sensitivity of electrochemical sensors. Since most biomarkers, especially those associated with diseases such as cancer, exist in trace amounts, sensitive detection is essential for them. However, it is a considerable challenge to develop anti-fouling interface strategies that can achieve highly sensitive electrochemical sensing in complex matrixes. Herein, a novel biomimetic anti-fouling interface engineering strategy was constructed based on thorn-vine-like structure for electrochemical biosensing. Bovine serum albumin (BSA) and sulfobetaine methacrylate (SBMA) underwent a thiol-ene click reaction, followed by electrostatic interaction with multi-walled carbon nanotubes (MWCNT), resulting in the thorn-vine-like structure BSA-PSBMA-MWCNT (BPSMC), with a highly three-dimensional network structure. The BPSMC not only significantly reduced non-specific adsorption, but also effectively enhanced the ability of the sensing interface to transfer electrons to the electrode surface. The impedance change ratio of the BPSMC-modified glassy carbon electrodes (GCE) was only 5.30% compared to the bare GCE when treated in undiluted serum samples for 2 h. As a proof of concept, the tumor biomarker ferritin (FER) was applied as a model analyte. By functionalizing the interface with specific antibodies, it enables quantification of FER in undiluted serum samples with ultra-high sensitivity. This biomimetic anti-fouling interface engineering strategy possesses excellent anti-fouling properties, sensitivity, and universality and offers great potential for anti-fouling interfaces in complex matrices for medical and non-medical applications.