Ultra-sensitive dielectrophoretic surface charge multiplex detection inside a micro-dielectrophoretic device

Area of Science:

• Analytical Chemistry
• Nanotechnology
• Biomolecular Engineering

Background:

• Label-free dielectrophoretic (DEP) force-based surface charge detection offers high sensitivity for detecting analytes.
• Current DEP methods face challenges in multiplex detection due to complex calibration and signal interference.

Purpose of the Study:

• To develop a novel method for overcoming limitations in multiplex dielectrophoretic detection.
• To enable sensitive and selective label-free detection of multiple analytes simultaneously.

Main Methods:

• Developed a method using optical discrimination of dielectrophoretic behaviors of multiple microparticle probes.
• Utilized surface charge differences before and after self-assembling conjugation of probes.
• Functionalized particle probes with DNA aptamers for specific analyte binding.

Main Results:

• Achieved attomolar limit of detection (LOD) for Hg²⁺ in distilled water and femtomolar LOD in drinking water using DNA aptamer-functionalized probes.
• Demonstrated the first label-free dielectrophoretic multiplex detection of Hg²⁺ and Ag⁺ in drinking water.
• Attained femtomolar LOD for Hg²⁺ and nanomolar LOD for Ag⁺ in multiplex detection.

Conclusions:

• The developed optical discrimination method enhances multiplex dielectrophoretic detection capabilities.
• This technique provides a sensitive and selective platform for label-free simultaneous detection of multiple targets.
• Opens new avenues for environmental monitoring and diagnostics.