Antifouling Peptoid Engineering Empowers Electrochemical Biosensor with Extraordinary Proteolytic Stability for Rigorous Analysis of Neuron-Specific Enolase in Diverse Biofluids.

A facile and versatile antifouling sensor capable of assaying targets in diverse biological fluids was developed based on engineered peptoids with improved proteolytic stability. As peptidomimetics featuring N-substituted glycine backbones, the engineered peptoids are anchored by d-Cys, linked by (d-Pro)4 fragment, and notably, employs four NENK dimers for antifouling. Benefiting from the unique structure and deliberate design of peptoids, the fabricated material possesses excellent biocompatibility. Meanwhile, these distinct functional domains act synergistically to enhance the overall performance of antifouling materials, especially in terms of stability. Ultralow-fouling and highly sensitive electrochemical sensing of neuron-specific enolase (NSE) was realized via one-step coimmobilization of the peptoids and aptamers onto glassy carbon electrodes (GCEs) modified with electrodeposited poly(3,4-ethylenedioxythiophene) (PEDOT) and gold nanoparticles. The as-proposed peptoid-based biosensor demonstrated a decent analytical performance toward NSE detection, featuring a relatively wide linear range from 0.001 to 500 ng mL-1, with an satisfactory accuracy in detecting NSE in human tear and clinical serum samples. The design strategy of these peptoids endow biosensors with impressive antifouling power in diverse biological fluids, as well as enhanced stability toward proteolytic hydrolysis by trypsin and alkaline protease. By integrating the superior stability of peptoids with an efficient antifouling design, this strategy provides solid theoretical support for accurate and sensitive protein detection in complex biological fluids, and offers a new route to develop analogous electrochemical sensing platforms.