A tripod anchor offers improved robustness of peptide-based electrochemical biosensors

Peptide-based electrochemical biosensors have proven to be powerful sensing strategies for the detection of proteases and offer a highly versatile system, as simple tuning of the immobilised substrate peptide leads to a new sensing platform. The most common immobilisation strategy of peptides onto an electrode surface is via a self-assembled monolayer (SAM) through a thiol group that can be readily chemically incorporated in the target peptide. However, the successful application of these platforms in complex biological samples can be frustrated by the lack of stability of the peptide-based SAM, that can lead to false positives and limited shelf-life. Herein, we investigated the stability of a peptide-based electrochemical platform endowed with a single or a tribranched thiol group for attaching onto the electrode surface. Side-by-side comparison demonstrated that the tripod anchor generated a highly robust peptide-based electrochemical biosensor that showed improved stability when compared to the monoanchor analogue, simplifying data analysis and interpretation, while showing efficient protease detection and similar sensing capabilities.