Aptamer-based sensing of β-casomorphin-7

Area of Science:

• Biochemistry
• Molecular Biology
• Analytical Chemistry

Background:

• Beta-casomorphin-7 (BCM-7) is a peptide derived from A1 beta-casein, linked to potential health concerns.
• Developing specific detection methods for BCM-7 is crucial for health-related research.

Purpose of the Study:

• To identify and characterize single-stranded DNA (ssDNA) aptamers with high affinity for BCM-7.
• To develop a novel aptamer-based assay for BCM-7 detection in biological samples.

Main Methods:

• Systematic evolution of ligands by exponential enrichment (SELEX) was used to select ssDNA aptamers against BCM-7.
• Binding affinities were quantified using dissociation constant (Kd) values.
• Aptamer-aptamer interactions were assessed using aptamer-coated gold nanoparticles (GNPs) and an enzyme-linked aptamer-sorbent assay (ELASA).

Main Results:

• Fifteen high-affinity ssDNA aptamers for BCM-7 were identified, with Kd values ranging from 7.7 to 156.7 nM.
• The Seq6 aptamer showed the lowest Kd value, indicating the highest affinity.
• Aptamer-coated GNPs exhibited a visible color change in the presence of BCM-7, confirming recognition.
• The developed ELASA demonstrated BCM-7 detection in various biological fluids, including urine, plasma, and digest samples.

Conclusions:

• ssDNA aptamers can be effectively selected for high-affinity binding to BCM-7.
• Aptamer-based nanotechnology, like GNP colorimetric assays, offers a visual detection method for BCM-7.
• The ELASA provides a promising platform for quantifying BCM-7 in complex biological matrices.