Periodic Reporting for period 4 - ABODYFORCE (High Throughput Microfluidic Cell and Nanoparticle Handling by Molecular and Thermal Gradient Acoustic Focusing)
Periodo di rendicontazione: 2024-05-01 al 2025-07-31
The project pushed the limits of microscale ultrasound-based technology to enable access to diagnostically important rare constituents of blood within minutes from blood draw.
To address the growing need for faster results in healthcare, the project focused on shifting from heavy, centralized laboratory equipment to point-of-care tests and patient self-testing. A key challenge for such devices is the ability to simultaneously measure multiple parameters while maintaining reasonable cost and compact size. Microscale technologies that can process small volumes of blood and deliver results within minutes were therefore targeted. The high precision and potential for multi-stage serial processing offered by microfluidic methods also allowed for rapid and automated isolation of rare cell populations, such as circulating tumor cells, and controlled high-throughput size fractionation of sub-micron biological particles, including platelets, pathogens, and extracellular vesicles.
To achieve fast and effective separation of blood components, blood was exposed to acoustic radiation forces in a flow-through format. By exploiting a newly discovered acoustic body force arising from local variations in the acoustic properties of the cell suspension, the project generated self-organizing configurations of blood cells. Acoustic cell organization was tailored and tuned through time modulation of the acoustic field, manipulation of the fluid’s acoustic properties using solute molecules, and through the novel concept of sound interaction with thermal gradients.
The project produced new fundamental knowledge on the acoustic properties of single cells and established a comprehensive theoretical framework for predicting cellular responses in any aqueous medium, bounding geometry, or sound field, laying the groundwork for potential new diagnostic methods.
To address the growing need for faster results in healthcare, the project focused on shifting from heavy, centralized laboratory equipment to point-of-care tests and patient self-testing. A key challenge for such devices is the ability to simultaneously measure multiple parameters while maintaining reasonable cost and compact size. Microscale technologies that can process small volumes of blood and deliver results within minutes were therefore targeted. The high precision and potential for multi-stage serial processing offered by microfluidic methods also allowed for rapid and automated isolation of rare cell populations, such as circulating tumor cells, and controlled high-throughput size fractionation of sub-micron biological particles, including platelets, pathogens, and extracellular vesicles.
To achieve fast and effective separation of blood components, blood was exposed to acoustic radiation forces in a flow-through format. By exploiting a newly discovered acoustic body force arising from local variations in the acoustic properties of the cell suspension, the project generated self-organizing configurations of blood cells. Acoustic cell organization was tailored and tuned through time modulation of the acoustic field, manipulation of the fluid’s acoustic properties using solute molecules, and through the novel concept of sound interaction with thermal gradients.
The project produced new fundamental knowledge on the acoustic properties of single cells and established a comprehensive theoretical framework for predicting cellular responses in any aqueous medium, bounding geometry, or sound field, laying the groundwork for potential new diagnostic methods.
WP1 – Acoustically Packed Blood:
This work package focused on understanding the behavior of blood under acoustic forces. Experiments on acoustically packed red blood cells revealed distinct streaming patterns, with four rolls forming inside the packed RBC bed and four additional rolls in the surrounding plasma. Neighboring rolls rotated in the same direction, likely due to viscosity contrasts, and RBC streaming was slower and flatter than plasma streaming. These observations provide fundamental insight into the physics of dense cell suspensions under acoustic fields, forming the basis for later work on single-cell behavior and separation. We demonstrated that the effect can be applied to cell separation of rare cells in a flow-through configuration. These results have been published in Analytical Chemistry, highlighting both mechanistic understanding and practical applications of this phenomenon.
WP2 – Single-Cell Measurements and Cell Separation:
In this work package we developed novel methods for quantitative characterization of individual cells and exploited these properties for cell separation. A key achievement was a technique to measure the density of single cells, linking mechanical cell properties to their response in acoustic fields. Using this knowledge, several studies demonstrated label-free acoustic separation of blood cells and other cell types, including peripheral blood mononuclear cells and circulating tumor cells. These results have been published in Physical Review Applied, Scientific Reports, and Analytical Chemistry, highlighting both mechanistic understanding and practical applications in cell sorting and enrichment.
WP3 – Thermoacoustic Streaming:
In this work package we explored the interplay between acoustic and thermal fields in microfluidic channels. By using laser-induced local temperature gradients, experiments demonstrated configurable microscale streaming, with velocities far exceeding conventional acoustic streaming. The relative orientation of sound and thermal fields was critical: perpendicular configurations increased streaming velocities over 100-fold compared to parallel ones, due to directional differences in the induced body force. Time-resolved studies quantified the build-up and decay of streaming flows, and observations were in qualitative agreement with finite-element simulations. These insights are foundational for precise microfluidic manipulation using thermoacoustic effects and have been published in Physical Review Letters, Physical Review Applied, and Physical Review E.
Dissemination and exploitation: The results have been published in journal papers and presented at Acoustofluidics 2021-2024 and MicroTAS 2023. Beyond fundamental understanding, the project outcomes provide a strong basis for developing acoustofluidic devices for rare-cell isolation, label-free cell sorting, and programmable microfluidic manipulation.
This work package focused on understanding the behavior of blood under acoustic forces. Experiments on acoustically packed red blood cells revealed distinct streaming patterns, with four rolls forming inside the packed RBC bed and four additional rolls in the surrounding plasma. Neighboring rolls rotated in the same direction, likely due to viscosity contrasts, and RBC streaming was slower and flatter than plasma streaming. These observations provide fundamental insight into the physics of dense cell suspensions under acoustic fields, forming the basis for later work on single-cell behavior and separation. We demonstrated that the effect can be applied to cell separation of rare cells in a flow-through configuration. These results have been published in Analytical Chemistry, highlighting both mechanistic understanding and practical applications of this phenomenon.
WP2 – Single-Cell Measurements and Cell Separation:
In this work package we developed novel methods for quantitative characterization of individual cells and exploited these properties for cell separation. A key achievement was a technique to measure the density of single cells, linking mechanical cell properties to their response in acoustic fields. Using this knowledge, several studies demonstrated label-free acoustic separation of blood cells and other cell types, including peripheral blood mononuclear cells and circulating tumor cells. These results have been published in Physical Review Applied, Scientific Reports, and Analytical Chemistry, highlighting both mechanistic understanding and practical applications in cell sorting and enrichment.
WP3 – Thermoacoustic Streaming:
In this work package we explored the interplay between acoustic and thermal fields in microfluidic channels. By using laser-induced local temperature gradients, experiments demonstrated configurable microscale streaming, with velocities far exceeding conventional acoustic streaming. The relative orientation of sound and thermal fields was critical: perpendicular configurations increased streaming velocities over 100-fold compared to parallel ones, due to directional differences in the induced body force. Time-resolved studies quantified the build-up and decay of streaming flows, and observations were in qualitative agreement with finite-element simulations. These insights are foundational for precise microfluidic manipulation using thermoacoustic effects and have been published in Physical Review Letters, Physical Review Applied, and Physical Review E.
Dissemination and exploitation: The results have been published in journal papers and presented at Acoustofluidics 2021-2024 and MicroTAS 2023. Beyond fundamental understanding, the project outcomes provide a strong basis for developing acoustofluidic devices for rare-cell isolation, label-free cell sorting, and programmable microfluidic manipulation.
This project has advanced the state of the art in acoustofluidics in two major areas: acoustic packing of blood and thermoacoustic streaming in liquids. Both phenomena were demonstrated here for the first time, providing new avenues for fundamental studies and practical applications in microfluidics.
Acoustic packing of blood: Previous acoustophoretic studies largely focused on single-cell manipulation or dilute suspensions. Our work established that dense blood suspensions can be organized into acoustically packed beds, revealing rich streaming structures within and around the packed red blood cells. This provides the first experimental demonstration of how acoustic forces and viscosity contrasts shape flow patterns in dense cellular suspensions. Understanding these interactions enables precise control of cell positioning, which is critical for downstream applications such as selective cell separation, rare-cell enrichment, and label-free diagnostics.
Thermoacoustic streaming in liquids: Traditional acoustic streaming relies solely on viscous dissipation, limiting the achievable flow velocities and spatial control. In contrast, this project demonstrated thermoacoustic streaming, where temperature gradients induce a nondissipative acoustic body force that can generate controllable streaming with velocities orders of magnitude higher than conventional acoustic streaming. The ability to tune flow patterns by adjusting the thermal gradient direction, magnitude, and temporal dynamics represents a step-change in microfluidic manipulation. This effect has been characterized experimentally and modeled qualitatively with finite-element simulations, establishing a solid foundation for future device engineering.
Acoustic packing of blood: Previous acoustophoretic studies largely focused on single-cell manipulation or dilute suspensions. Our work established that dense blood suspensions can be organized into acoustically packed beds, revealing rich streaming structures within and around the packed red blood cells. This provides the first experimental demonstration of how acoustic forces and viscosity contrasts shape flow patterns in dense cellular suspensions. Understanding these interactions enables precise control of cell positioning, which is critical for downstream applications such as selective cell separation, rare-cell enrichment, and label-free diagnostics.
Thermoacoustic streaming in liquids: Traditional acoustic streaming relies solely on viscous dissipation, limiting the achievable flow velocities and spatial control. In contrast, this project demonstrated thermoacoustic streaming, where temperature gradients induce a nondissipative acoustic body force that can generate controllable streaming with velocities orders of magnitude higher than conventional acoustic streaming. The ability to tune flow patterns by adjusting the thermal gradient direction, magnitude, and temporal dynamics represents a step-change in microfluidic manipulation. This effect has been characterized experimentally and modeled qualitatively with finite-element simulations, establishing a solid foundation for future device engineering.