Highly Multiplexed Label-Free Imaging Sensor for Accurate Quantification of Small-Molecule Binding Kinetics

Area of Science:

• Biotechnology
• Biosensor Technology
• Analytical Chemistry

Background:

• Small molecule interactions with large ligands are crucial for drug development and agro-biotechnology.
• Current biosensor technologies often face limitations in detecting low molecular weight compounds.
• Label-free, highly multiplexed biosensing offers a promising avenue for sensitive molecular detection.

Purpose of the Study:

• To improve the limit of detection for the Interferometric Reflectance Imaging Sensor (IRIS) for small-molecule screening.
• To demonstrate the characterization of small molecules binding to immobilized probes in a microarray format.
• To validate the optimized IRIS system by screening antibodies against a mycotoxin.

Main Methods:

• Utilized Interferometric Reflectance Imaging Sensor (IRIS) for label-free, highly multiplexed biosensing.
• Optimized system parameters, including spatial and temporal averaging, to minimize noise and maximize signal-to-noise ratio (SNR).
• Performed small-molecule binding assays using biotin-streptavidin interaction and antibody-mycotoxin (fumonisin B1) screening.

Main Results:

• Achieved a limit of detection of 1 pg/mm² in mass density for small molecules.
• Demonstrated a high SNR (≈ 34) for biotin detection and a good SNR (≈ 8) for mycotoxin screening.
• Validated results with a lateral flow assay, showing consistency with IRIS screening.

Conclusions:

• The enhanced IRIS system significantly improves small-molecule detection sensitivity.
• The optimized biosensor is effective for screening low molecular weight compounds like mycotoxins.
• Future advancements in camera sensor technology are expected to further enhance biosensor sensitivity.