Protein detection with a novel ISFET-based zeta potential analyzer

Area of Science:

• Electrochemistry
• Biosensing technology
• Surface chemistry

Background:

• Zeta potential measurement is crucial for detecting protein accumulation on surfaces.
• Existing methods for zeta potential determination can be complex and reagent-intensive.
• Novel biosensor platforms are needed for efficient and sensitive surface analysis.

Purpose of the Study:

• To present a novel ISFET-based measurement concept for zeta potential determination.
• To develop and validate a simulation model for the biosensor's measurement principle.
• To demonstrate the biosensor's feasibility for protein detection and immunosensing applications.

Main Methods:

• Utilized a novel setup with two monolithically integrated ISFET sensors in a serial flow configuration.
• Developed a simulation model based on site-binding theory, considering proton dissociation and electrolyte ion influence.
• Employed a quasi-Newton iteration for numerical solution and experimentally validated results with modified fused silica capillaries.

Main Results:

• The developed ISFET biosensor system is characterized by small size, low reagent consumption, and effective noise suppression.
• The simulation model accurately represents surface effects and zeta potential variations with pH.
• Demonstrated a significant shift in zeta potential upon covalent coupling of lysozyme, validating the immunosensor concept.

Conclusions:

• The novel ISFET-based biosensor provides an efficient, compact, and sensitive platform for zeta potential measurement.
• The theoretical model offers a satisfactory basis for describing surface effects in biosensing.
• The system shows high potential for developing advanced immunosensors for protein detection.