High-performance surface acoustic wave immunosensing system on a PEG/aptamer hybridized surface.

Area of Science:

• Biomolecular Engineering
• Surface Chemistry
• Biosensor Technology

Background:

• Label-free immunoassay systems offer procedural simplicity and cost-effective surface construction for biosensing.
• Polyethylene glycol (PEG) is widely used as a blocking agent to prevent nonspecific adsorption in biosensor surfaces.
• The co-immobilization strategy of PEG and ligands significantly impacts assay performance due to ligand-surface interactions.

Purpose of the Study:

• To investigate the interaction between thrombin and a thrombin-binding aptamer (TBA) on a PEG/TBA co-immobilized surface.
• To understand how PEG density and aptamer distance from the surface influence thrombin-TBA binding.
• To optimize surface construction for high-performance label-free immunosensing.

Main Methods:

• Utilized a shear horizontal surface acoustic wave (SAW) sensor for label-free detection.
• Developed PEG/TBA co-immobilized surfaces with varying PEG densities and aptamer distances.
• Analyzed the binding properties of thrombin to the TBA on the modified surfaces.

Main Results:

• Thrombin-TBA binding affinity demonstrated significant sensitivity to changes in PEG density.
• The distance between the aptamer and the gold surface critically affected the binding characteristics.
• Identified optimal PEG densities and aptamer positioning for enhanced thrombin detection.

Conclusions:

• Surface construction strategies for PEG/ligand co-immobilization are vital for biosensor performance.
• PEG density and aptamer orientation play key roles in modulating target analyte binding.
• Findings provide insights for designing improved label-free aptasensors for thrombin detection.