A simple displacement aptamer assay on resistive pulse sensor for small molecule detection

Area of Science:

• Biotechnology
• Nanotechnology
• Analytical Chemistry

Background:

• Aptamer-based sensing offers high specificity for molecular targets.
• Nanocarriers enhance sensitivity and enable efficient analyte capture.
• Resistive Pulse Sensing (RPS) provides label-free detection capabilities.

Purpose of the Study:

• To develop a universal aptamer-based sensing strategy for rapid, label-free detection of small molecules.
• To utilize DNA-modified nanocarriers and RPS for enhanced sensitivity and versatility.
• To demonstrate simultaneous detection of multiple analytes.

Main Methods:

• Modification of magnetic nanocarriers with ssDNA anchors and aptamers to form dsDNA complexes.
• Induction of aptamer release upon target molecule binding, altering nanocarrier surface properties.
• Measurement of nanocarrier velocity changes using RPS as a proxy for target concentration.

Main Results:

• Demonstrated rapid (≤20 min) and label-free detection of Moxifloxacin, Imatinib, and Irinotecan.
• Showcased simultaneous detection of Imatinib and Moxifloxacin using size-differentiated nanocarriers.
• Confirmed that aptamer length and nanocarrier preconcentration influence assay sensitivity.

Conclusions:

• The proposed strategy is versatile, adaptable to various targets, and not dependent on aptamer tertiary structure.
• The use of nanocarriers with different diameters allows for multiplexed detection of analytes.
• This method provides a robust platform for sensitive and rapid small molecule detection.