Aptamer-aptamer linkage based aptasensor for highly enhanced detection of small molecules

Area of Science:

• Nanotechnology
• Analytical Chemistry
• Biotechnology

Background:

• Multi-target colorimetric aptasensors typically use two aptamer sequences.
• Enhancing colorimetric signals via gold nanoparticle (AuNP) aggregation properties remains underexplored.
• Existing aptasensors lack efficient methods for signal control and enhancement.

Purpose of the Study:

• To develop a simple and efficient method to control and enhance multi-target aptasensor function.
• To achieve highly sensitive multiple-target detection of small molecules.
• To investigate the mechanism behind enhanced sensitivity using an aptamer-aptamer linkage.

Main Methods:

• Fabrication of a multi-target aptasensor utilizing an aptamer-aptamer linkage method.
• Extension of aptamer DNA sequences to improve analytical sensitivity.
• Zeta potential measurements to study DNA aptamer-AuNP interactions and elucidate the enhancement mechanism.

Main Results:

• The aptamer-aptamer linkage method successfully enhanced the analytical sensitivity of the multi-target aptasensor.
• Achieved limits of detection (LOD) of 1 nM for kanamycin (KAN) and 37 nM for chlortetracycline (CHLOR).
• Demonstrated a 25-fold lower LOD for KAN and a five-fold lower LOD for CHLOR compared to previous AuNP-based sensors.

Conclusions:

• The developed aptasensor offers a simple and efficient approach for enhancing multi-target detection.
• The aptamer-aptamer linkage strategy significantly boosts analytical sensitivity and lowers detection limits.
• This aptasensor shows great potential for simultaneous detection of kanamycin and chlortetracycline over a wide concentration range.