Quantitatively Elucidating the Trade-Off between Zwitterionic Antifouling Surfaces and Bioconjugation Performance

Area of Science:

• Biomaterials Science
• Surface Chemistry
• Biosensor Technology

Background:

• Zwitterionic materials offer excellent hydrophilicity, minimizing nonspecific biomolecule adsorption.
• However, antifouling properties can impede specific target capture by immobilized probes.
• Developing surfaces balancing antifouling and capture efficiency is crucial for biosensors.

Purpose of the Study:

• To investigate the impact of zwitterionic (PEDOT-PC) content on antifouling properties and peptide-protein capture efficiency.
• To model the relationship between antifouling characteristics and specific binding in a peptide-protein system.
• To validate the utility of designed surfaces for biosensing.

Main Methods:

• Fabrication of poly(3,4-ethylenedioxythiophene) (PEDOT) surfaces with varying phosphorylcholine (PC) and maleimide ratios.
• Utilizing quartz crystal microbalance with dissipation (QCM-D) to monitor protein adsorption and binding kinetics.
• Employing electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV) for electrochemical characterization.

Main Results:

• Increasing PEDOT-PC content enhanced antifouling properties, reducing nonspecific protein adsorption.
• Higher PEDOT-PC concentrations significantly decreased the specific binding efficiency of calmodulin (CaM) to the peptide probe.
• A quantitative equation was proposed to describe the observed binding behavior.
• Electrochemical methods confirmed increased impedance with protein adsorption, validating surface utility.

Conclusions:

• Zwitterionic PEDOT-PC surfaces effectively reduce protein fouling but compromise specific capture efficiency.
• The study provides a quantitative understanding of the antifouling-capture efficiency trade-off.
• The designed surfaces demonstrate practical utility for biosensing applications where fouling is a concern.