Space-time acoustofluidic tweezers for dynamic and selective manipulation of microparticles

Area of Science:

• Acoustofluidics
• Biomedical Engineering
• Microparticle Manipulation

Background:

• Dynamic acoustofluidics offers precise, contact-free manipulation of microscale entities.
• Current methods lack contrast-based selective control due to time-invariant pressure fields.

Purpose of the Study:

• To introduce a novel space-time acoustofluidic tweezer (STAT) for dynamic, contrast-dependent manipulation.
• To enable selective control and sorting of microparticles and cells based on acoustic properties.

Main Methods:

• Utilized frequency detuning for pseudo-space-time modulation of standing surface acoustic waves.
• Employed STAT to induce harmonic motions in particles with positive (PACP) and negative (NACP) acoustic contrast.
• Conducted experiments and simulations to validate the manipulation capabilities.

Main Results:

• Demonstrated low-frequency, shear-like harmonic motion for PACPs and longitudinal-like motion for NACPs.
• Showcased selective guiding of NACPs along programmed paths while PACPs remained patterned.
• Confirmed STAT's ability to differentiate and control particles based on acoustic contrast.

Conclusions:

• STAT provides a gentle, biocompatible method for selective particle manipulation and sorting.
• This technology enhances the capabilities of acoustofluidic systems for biomedical applications.
• Enables dynamic, contrast-dependent control of microparticles and cells.