HaloTag-Modified, Ferrocene Labeled Self-Assembled Monolayers for Protein Sensing

Area of Science:

• Electrochemistry
• Surface Science
• Biomolecular Engineering

Background:

• Self-assembled monolayers (SAMs) are crucial for modifying electrode surfaces.
• Ferrocene (Fc) is a versatile redox reporter for electrochemical sensing.
• Protein detection on surfaces requires strategies to minimize fouling and maximize specificity.

Purpose of the Study:

• To investigate the antifouling and specific detection capabilities of Fc-based SAMs.
• To explore the influence of Fc positioning within the SAM on protein interactions.
• To demonstrate a proof-of-concept for electrochemical detection of HaloTag protein.

Main Methods:

• Fabrication of mixed SAMs using Fc-based molecules and a PEG2 diluent.
• Electrochemical characterization (cyclic voltammetry, capacitance measurements) before and after protein exposure.
• Orthogonal validation using SAMs for MALDI mass spectrometry (SAMDI-MS).

Main Results:

• Fc-SAMs exhibited antifouling properties, reducing nonspecific adsorption.
• Specific detection of HaloTag protein was achieved, with Fc position influencing signal.
• Increased disorder and ion mobility were observed upon protein binding.
• SAMDI-MS confirmed HaloTag protein binding to the functionalized electrodes.

Conclusions:

• Fc-based SAMs offer a promising platform for antifouling and specific protein detection.
• Controlling the architecture of Fc-SAMs is key to optimizing sensor performance.
• The study provides insights into designing electrochemical biosensors with enhanced selectivity and reduced fouling.