Engineering constructed of high selectivity dexamethasone aptamer based on truncation and mutation technology

Area of Science:

• Biotechnology
• Analytical Chemistry
• Molecular Biology

Background:

• Aptamer-based biosensors are popular for rapid detection.
• Biosensor performance relies heavily on aptamer affinity.
• Optimizing aptamer sequences is crucial for enhanced sensitivity and selectivity.

Purpose of the Study:

• To develop a strategy for constructing high-affinity aptamers.
• To improve the sensitivity and selectivity of aptamers for dexamethasone (DEX) detection.
• To establish a general method for aptamer sequence optimization.

Main Methods:

• Truncation of flanking bases in the original DEX aptamer sequence.
• Introduction of base mutations to further enhance aptamer properties.
• Characterization of the optimized aptamer (Apt-M13) using G-quadruplex structures.
• Determination of dissociation constant (Kd) using graphene oxide (GO)-based fluorometry.
• Development of a label-free colorimetric aptamer sensor using gold nanoparticles.

Main Results:

• A 33 nt aptamer (Apt-M13) with G-quadruplex structures was obtained.
• The dissociation constant (Kd) for Apt-M13 was determined to be 200 nM.
• The developed aptamer sensor exhibited a 3.2-fold lower limit of detection (LOD) compared to the original aptamer.
• Improved anti-interference ability against DEX analogs was observed.
• Truncation and mutation strategies effectively enhanced aptamer specificity, affinity, and selectivity for DEX.

Conclusions:

• The proposed aptamer optimization strategy, involving truncation and mutation, significantly improves aptamer performance for DEX detection.
• The optimized Apt-M13 aptamer enables highly sensitive and selective detection of DEX.
• This method offers a generalizable approach for enhancing various aptamer sequences for biosensing applications.