New immobilization method for immunoaffinity biosensors by using thiolated proteins

Area of Science:

• Biomedical Engineering
• Biosensor Technology
• Surface Chemistry

Background:

• Immunoaffinity (IA) biosensors require stable and dense layers of biomolecules for optimal performance.
• Current immobilization methods can compromise biomolecule integrity and surface density.
• Developing robust immobilization techniques is crucial for advancing biosensor sensitivity and reliability.

Purpose of the Study:

• To develop and validate a new immobilization method for IA biosensors.
• To ensure high surface density and stability of the immunoaffinity layer.
• To assess the feasibility of the developed method for biosensor applications.

Main Methods:

• Biomolecules (horseradish peroxidase and antibody) were thiolated via covalent conjugation of mercaptopropionic acid.
• Thiolated proteins were immobilized onto a gold transducer surface.
• Properties evaluated included biological integrity (activity assay), charge transfer resistance, mass loading (SPR), binding sites, and capacitive change.

Main Results:

• The thiolation method successfully immobilized biomolecules while maintaining biological integrity.
• Surface plasmon resonance (SPR) confirmed high mass loading and a significant number of binding sites.
• The immobilization process demonstrated stability and feasibility for antigen-antibody interactions.

Conclusions:

• The developed thiolation-based immobilization method is effective for creating stable and dense immunoaffinity layers on gold surfaces.
• This method preserves biomolecule activity and offers a high density of binding sites, suitable for IA biosensor development.
• The technique shows significant promise for enhancing the performance and applicability of immunoaffinity biosensors.