Microbubble-Label Cell Sorting via Traveling Acoustic Waves
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Solution Overview
Problem
Current cell sorting technologies, such as FACS and MACS, are costly, require large sample volumes, and have limitations in availability and efficiency, particularly for small labs, while ultrasound-based methods face challenges with density and morphology differences between particles and are sensitive to environmental changes.
Innovation Solution
A cell-sorting system utilizing microbubble-labeled cells and traveling acoustic waves to separate cells, where microbubbles interact strongly with ultrasound, allowing for efficient displacement of labeled cells relative to unlabeled cells, enabling high-throughput, low-cost, and label-free sorting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If FACS or MACS are used for cell separation, then cell identification and separation can be achieved, but the cost is high and large sample volumes are required
Solution Approach 1:
The patent replaces the mechanical/optical systems of FACS (fluorescent labeling and optical detection) and MACS (magnetic particle labeling and magnetic field separation) with an acoustic system using microbubble labeling and acoustic radiation force. Microbubbles are conjugated to cell surface antigens and manipulated using acoustic waves to achieve separation based on acoustic impedance differences, eliminating the need for expensive fluorescent/magnetic labels and large sample volumes.
Solution Approach 2:
The patent changes the physical parameter used for cell separation from optical properties (FACS) or magnetic properties (MACS) to acoustic properties. By using microbubbles with different acoustic impedances attached to cells, the system exploits acoustic radiation force differences to separate cells, enabling high precision with smaller sample volumes.
2Ease of manufacture
If standing ultrasound waves are used for cell separation, then label-free separation can be achieved, but significant density or morphology differences are required between particles
Solution Approach 1:
The patent introduces microbubbles as an intermediary between the acoustic field and the cells. Instead of relying on direct acoustic interaction with cells (which requires significant density/morphology differences), microbubbles are conjugated to cell surface antigens. These microbubbles have strong acoustic impedance contrasts with the surrounding medium, enabling effective label-free separation while expanding versatility to various cell types regardless of their inherent acoustic properties.
3Force
If standing waves are used for cell sorting, then separation forces can be strong, but the system is sensitive to environmental changes such as temperature
Solution Approach 1:
The patent inverts the traditional standing wave approach by using traveling acoustic waves instead. While standing waves create strong forces at pressure nodes, they are highly sensitive to environmental changes. Traveling waves provide continuous acoustic radiation force along the propagation direction, maintaining strong separation forces while being more robust to temperature and environmental fluctuations, thus improving reliability.
4Ease of manufacture
If magnetic bead sorting is used, then cost is reduced, but fewer antibodies are available for conjugation and enzymatic digestion is needed
Solution Approach 1:
The patent substitutes magnetic bead conjugation with microbubble conjugation. Magnetic beads require enzymatic digestion for removal and have limited antibody availability. Microbubbles can be easily conjugated to a wide range of antibodies and other ligands targeting cell surface antigens, and they can be removed by simple physical methods (e.g., acoustic disruption or filtration) without enzymatic digestion, maintaining cost effectiveness while significantly improving versatility.
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
The system achieves efficient separation of cells with specific surface antigens, allowing for rare cell detection and low sample volume sorting, while being more stable and cost-effective than existing methods, with microbubble-labeled cells being displaced by significant distances relative to unlabeled cells.
Implementation Method 1
the one or more acoustic transducers is positioned and configured to deliver a traveling acoustic wave through the flow channel, wherein the traveling acoustic wave applies an acoustic radiation force to a sample flowing through the flow channel such that the microbubble-labeled cells are displaced relative to unlabeled cells
Data Source
AI summary
Cell-separation systems and methods utilizing cell-specific microbubble tags and ultrasound-based separation are described. The methods are useful for simplification of time-consuming and costly cell purification procedures and real time apoptosis detection.