Generation of highly specific aptamers via micromagnetic selection

Area of Science:

• Biotechnology
• Molecular Biology
• Nanotechnology

Background:

• Aptamers are nucleic acid-binding molecules with high affinity and specificity for target molecules.
• Traditional aptamer generation methods like SELEX are time-consuming and labor-intensive.
• Microfluidic SELEX (M-SELEX) offers accelerated aptamer isolation under stringent conditions.

Purpose of the Study:

• To present an alternative M-SELEX method using a disposable microfluidic chip for rapid aptamer generation.
• To demonstrate the efficiency of micromagnetic separation (MMS) in isolating high-affinity and specific aptamers.
• To establish MMS-based SELEX as a general platform for aptamer discovery.

Main Methods:

• Development of a micromagnetic separation (MMS) chip with integrated microfabricated ferromagnetic structures.
• Utilizing the MMS chip for rapid aptamer enrichment under stringent selection conditions.
• Demonstration of DNA aptamer generation against streptavidin using three rounds of positive selection and one round of negative selection against BSA.

Main Results:

• The MMS chip demonstrated high bead recovery (99.5%) and efficient separation of weakly bound/unbound ssDNA.
• Picomolar amounts of target molecule were sufficient for selection.
• Generated DNA aptamers showed dissociation constants (Kd) of 25–65 nM for streptavidin and negligible affinity for BSA.

Conclusions:

• The developed MMS chip provides a facile, robust, and efficient platform for rapid aptamer generation.
• This method significantly accelerates the SELEX process, enabling the use of minimal target quantities.
• MMS-based SELEX is a versatile approach for generating specific aptamers against a wide range of molecular targets.