Acoustofluidic Trapping Matrix for Nonresonant Nanoparticle Capture
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing acoustofluidic methods struggle to efficiently trap and separate smaller biological nanoparticles due to low acoustic radiation forces and interference from acoustic streaming, making it difficult to handle particles below a critical radius, such as extracellular vesicles.
Innovation Solution
A method and system using an ultrasound transducer to couple acoustic waves into a substrate, generating secondary acoustic fields within a trapping matrix that traps particles by actuating at a frequency not corresponding to the cavity's resonance, allowing for the trapping of micro- and nanoparticles without the need for resonance matching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional acoustofluidic methods are used to trap particles, then larger particles can be trapped effectively, but smaller biological nanoparticles cannot be trapped due to low acoustic radiation forces and acoustic streaming interference
Solution Approach 1:
The patent introduces a trapping matrix as an intermediary medium between the ultrasound field and the particles. The matrix comprises particles with acoustic contrast factors that generate secondary acoustic fields, which in turn trap the target nanoparticles. This mediator approach allows indirect trapping of particles that would otherwise be too small to trap directly with acoustic radiation force.
Solution Approach 2:
The patent uses ultrasonic vibration at specific frequencies to generate acoustic fields that interact with the trapping matrix. By actuating the ultrasound transducer at frequencies that couple acoustic waves into the substrate without resonating the cavity, secondary acoustic fields are generated within the trapping matrix that enable nanoparticle trapping despite the presence of acoustic streaming.
2Productivity
If resonance frequency is used for particle trapping, then trapping efficiency is improved, but device complexity and tuning requirements increase
Solution Approach 1:
The patent inverts the conventional approach by not requiring the cavity to resonate at the trapping frequency. Instead, the ultrasound transducer is actuated at frequencies that do NOT correspond to cavity resonances, but which still couple acoustic waves into the substrate to generate the necessary secondary acoustic fields within the trapping matrix for effective nanoparticle trapping.
3Measurement precision
If smaller particles are targeted for trapping, then separation precision is improved, but the acoustic radiation force becomes insufficient to overcome acoustic streaming
Solution Approach 1:
The trapping matrix acts as an intermediary that amplifies the acoustic effect on small particles. The matrix particles, being larger and having sufficient acoustic contrast, generate strong secondary acoustic fields that exert adequate trapping forces on the target nanoparticles, overcoming the limitation of directly applying acoustic radiation force to very small particles.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables efficient trapping of nanoparticles at higher throughput and capacity, simplifying device construction and scalability, as demonstrated by the trapping of 380 nm nanoparticles at 50 µL/min, 500 times higher than previous methods, and up to 100 times larger volume.
Implementation Method 1
actuating the ultrasound transducer at an actuation frequency which couples an acoustic wave into the substrate
Implementation Method 2
an acoustic standing wave may be generated in the channel. This acoustic standing wave exerts a force, i.e. the acoustic radiation force, on the particles in the suspension
Implementation Method 3
the trapping matrix comprising or consisting of a material having a non-zero acoustic contrast factor relative to the suspending liquid
Implementation Method 4
The ultrasonic vibrations transmitted into the device do not only affect particles dispersed in the liquid, but also in the liquid itself by causing acoustic streaming
Data Source
Figure 1A~6
Figure 7~9
Figure 10A~10B
AI summary
A method of trapping particles, in a sample of a disperse liquid, having a non-zero acoustic contrast factor relative to a suspending liquid, comprising: i. providing an acoustofluidic device comprising a substrate in which a cavity is formed, the cavity being at least partially filled with a trapping matrix comprising or consisting of a material having a non-zero acoustic contrast factor, the cavity having an inlet for introducing the sample into the cavity, and an ultrasound transducer in acoustic contact with the substrate, ii. Introducing the sample into the cavity so the sample perfuses the trapping matrix, and iii. actuating the ultrasound transducer at an actuation frequency which does not correspond to a resonance of the cavity filled with the sample of disperse liquid, and couples an acoustic wave into the substrate. A system is also provided.