Shaped wall geometry with dielectrophoretic and laser forces for particle separation and characterization
Inventors
Hart, Sean J. • Staton, Sarah J. R. • Terray, Alexander V. • Collins, Gregory E.
Assignees
Publication Number
US-10618046-B2
Publication Date
2020-04-14
Expiration Date
2033-10-01
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Abstract
The combined value of integrating optical forces and electrokinetics allows for the pooled separation vectors of each to be applied, providing for separation based on combinations of features such as size, shape, refractive index, charge, charge distribution, charge mobility, permittivity, and deformability. The interplay of these separation vectors allow for the selective manipulation of analytes with a finer degree of variation. Embodiments include methods of method of separating particles in a microfluidic channel using a device comprising a microfluidic channel, a source of laser light focused by an optic into the microfluidic channel, and a source of electrical field operationally connected to the microfluidic channel via electrodes so that the laser light and the electrical field to act jointly on the particles in the microfluidic channel. Other devices and methods are disclosed.
Core Innovation
The invention integrates optical forces and electrokinetics within microfluidic channels to provide advanced particle separation based on multiple physical and chemical properties. By combining laser light and dielectrophoretic (DEP) electrical fields, particles can be separated based on size, shape, refractive index, charge, charge distribution, charge mobility, permittivity, and deformability. This dual-force approach allows for selective manipulation of analytes with a finer degree of variation than either force alone, providing a broader portfolio of separation vectors to probe chemical composition, geometry, and internal structure of particles.
The invention addresses the need for techniques for manipulation of analytes in liquids, specifically overcoming limitations of existing methods such as size-only based separation, reliance on biochemical tagging, or complex and costly instrumentation. The system incorporates a microfluidic platform with a laser light source focused via optics and a source of an electrical field applied through electrodes or shaped channel walls that generate DEP fields. Various configurations such as counter-flow, co-directional flow, orthogonal laser flow, and critical angle laser flow are disclosed, allowing tailored manipulation of particles including trapping, velocity modification, and sorting.
The interplay of laser optical forces and DEP enables the separation and characterization of particles in ways not possible with single-mode methods. For example, DEP traps with shaped wall geometry or obstructions can concentrate and separate particles for detailed optical probing. The combination of these forces facilitates not only the separation of particles from molecular species but also the identification and sorting of biological entities and other colloids without the need for chemical or immunological labeling.
Claims Coverage
The patent includes one independent claim focusing on a method of particle separation in a microfluidic channel using dielectrophoretic fields and optionally laser light to manipulate particles.
Dielectrophoretic field generation and configuration
Providing a microfluidic channel configured to supply a linear or non-linear dielectrophoretic (DEP) field into the channel via either a DEP electrode system or an insulator DEP system having shaped wall geometry or obstruction geometry, where the DEP field is generated at least in part by electrodes positioned at inlet and outlet ends and beyond the particle sorting region.
Application of DEP field to modify particle velocity
Flowing a plurality of particles in liquid through the microfluidic channel and operating the DEP field on the particles to change their velocity in the channel, thereby enabling particle separation.
Integration of laser light for particle manipulation
Optionally providing a source of laser light focused by an optic into the microfluidic channel, where the laser light can be focused axially either in the same direction or opposite direction to the fluid flow to assist in particle trapping, sorting, or velocity modification.
Using adjoining channel structures for particle elution
Trapping populations of particles in DEP traps and focusing laser light orthogonally to the flow axis to selectively elute one or more particle populations into an adjoining channel structure for further analysis or collection.
The claims cover a method combining shaped DEP field generation and manipulation of particle velocity within microfluidic channels, optionally enhanced by laser light at various orientations, including methods for particle trapping and selective elution via adjoining channels.
Stated Advantages
Provides high resolution separations by combining optical and electrokinetic forces sensitive to a wide range of particle properties including size, shape, refractive index, and charge.
Enables separation and characterization of biological and chemical species without the need for chemical or immunological tags.
Allows for selective trapping, manipulation, and elution of particle populations, facilitating downstream processing or analysis.
Permits fine discrimination between particles based on fundamentally different properties by using combined optical and dielectrophoretic forces.
Supports continuous high throughput separations and complex sorting schemes within a microfluidic environment.
Expands analytical capabilities for bio-warfare detection, biomedical analysis, and particle characterization beyond existing techniques.
Documented Applications
Separation and purified collection of colloidal samples such as organic particulates, inorganic particles, cells, bacteria, and viruses.
Distinguishing live versus dead organisms, cell cycle stages, blood cell types, cancer cells, infected cells, and abnormal cells.
Sorting particles based on shape, presence or absence of coatings, absorption characteristics, tagging status, and chemical or biochemical makeup.
Combined chemical, biochemical, and biological analysis and sorting, including bio-warfare agent detection.
Use in preparative separations mated to analytical detection schemes such as capillary electrophoresis, spectroscopy, culturing, and antibody studies.
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