A Continuum Modeling Approach to Nanoparticle Polarizability Characterization Using Fluorescence Intensity Profiles.

Area of Science:

• Nanotechnology
• Physical Chemistry
• Biophysics

Background:

• Dielectrophoresis (DEP) is widely used for manipulating electrically polarizable particles.
• Classical Clausius-Mossotti (CM) factor theories accurately describe macroscale particle DEP behavior.
• CM theories can be inaccurate for nanoscale particles, necessitating experimental validation.

Purpose of the Study:

• To develop and validate an integrated experimental-computational methodology for quantifying effective particle polarizabilities.
• To address the limitations of classical theories in describing nanoscale particle behavior under DEP.
• To establish a reliable method for determining particle polarizabilities where existing theories are inadequate.

Main Methods:

• Utilized dielectrophoresis (DEP) experiments with fluorescent nanoparticles.
• Developed a computational approach to simulate particle behavior under DEP.
• Compared experimental and simulated nanoparticle concentration profiles near electrodes.

Main Results:

• Successfully quantified effective particle polarizabilities for 52 and 105 nm nanoparticles.
• Obtained results showed good agreement with predictions from classical Clausius-Mossotti (CM) theory.
• Validated the experimental-computational methodology for accurate polarizability determination.

Conclusions:

• The presented methodology accurately quantifies effective particle polarizabilities from DEP experiments.
• The approach is suitable for nanoscale particles, overcoming limitations of classical CM theories.
• This work provides a calibration model and enables polarizability quantification for challenging particles.