Particle adhesion assay for microfluidic bifurcations
Inventors
Pant, Kapil • Prabhakarpandian, Balabhaskar • Sundaram, Shivshankar • Rea-Ramsey, Angela I.
Assignees
Publication Number
US-8828715-B2
Publication Date
2014-09-09
Expiration Date
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Abstract
A method for characterizing particle adhesion in microfluidic bifurcations and junctions comprises at least one idealized bifurcation or junction. Multiple bifurcations and/or junctions can be combined on a single microfluidic chip to create microfluidic networks configured for assays specifically to characterize particle interactions at junctions or to screen particles for desired interactions with microfluidic bifurcations and/or junctions.
Core Innovation
The present invention is an in-vitro method for characterizing one or more interactions of particles with one or more microfluidic bifurcations and/or junctions. Multiple bifurcations and/or junctions can be combined on a single microfluidic chip to create microfluidic networks configured for assays specifically to characterize particle interactions at junctions or to screen particles for desired interactions with microfluidic bifurcations and/or junctions.
The adhesion of particles such as leukocytes, platelets, liposomes/lipisomes, and microencapsulated drug carriers to microvascular endothelium is influenced by the geometric features of the vasculature, local hemodynamics, and numerous receptor-ligand interactions. This complex interplay between flow, cells, and particles is still poorly understood and it is not possible to predict, for example, adhesion patterns and numbers of adhered particles in the microvasculature based on current in-vitro flow cell technologies.
The present invention is based, in part, on the inventors' finding that microfluidic surfaces at bifurcations and junctions in biological and synthetic microvascular networks interact with particles moving through them to an unexpected degree and that interactions of particles at synthetic bifurcations are predictive of and correlate with particle interactions in physiological bifurcations. Idealized bifurcations, junctions, and combinations thereof fabricated using known technologies can be used to screen for particle and cell adhesion at corresponding structures in biological microvascular networks and to implement assays for characterizing or screening particle interactions.
Claims Coverage
The patent contains two independent method claims directed to (1) a method using an idealized microfluidic bifurcation and (2) a method using a plurality of idealized microfluidic bifurcations. The summary below extracts 17 main inventive features from these independent claims.
Microfluidic chip comprising an idealized microfluidic bifurcation
the idealized microfluidic bifurcation being a joint that fluidly couples a parent channel and two or more daughter channels
Locations of interest comprising a bifurcation wall with a coating
one or more locations of interest that include the idealized microfluidic bifurcation having a wall with a coating
Channel dimensions between 10 micrometers and 500 micrometers
the depth and width of each of the parent channel and daughter channels is between 10 micrometers and 500 micrometers
Daughter channel angles between 15 degrees and 135 degrees
the daughter channels each form an angle of between 15 degrees and 135 degrees at the idealized microfluidic bifurcation with respect to the parent channel
Flow causing particle interactions with the coating at the bifurcation
[procedural detail omitted for safety] Purpose: to cause at least a portion of the particles to interact with the coating at the idealized microfluidic bifurcation
Measuring particles interacting with the coating at locations of interest
[procedural detail omitted for safety] Purpose: to measure particles that interact with the coating at the one or more locations of interest
Determining distribution of particles on the coating with respect to the bifurcation
[procedural detail omitted for safety] Purpose: to determine the distribution of particles on the coating at the one or more locations of interest with respect to the idealized microfluidic bifurcation
Correlating distribution with interactions between particles and coating
[procedural detail omitted for safety] Purpose: to correlate the distribution of particles with one or more interactions between the particles and the coating of the idealized microfluidic bifurcation
Particles comprising various biological and particulate types
the particles are selected from the group consisting of cells, liposomes, lipisomes, lipoproteins, microencapsulated drugs, particulate drug carriers, nanoparticles, microparticles, polymer beads, viruses, spores and combinations thereof
Microfluidic chip comprising a plurality of idealized microfluidic bifurcations
each idealized microfluidic bifurcation is a joint that fluidly couples a parent channel and two or more daughter channels that are in fluid communication with the at least one inlet and at least one outlet
Locations of interest comprising each bifurcation with a well with a coating
one or more locations of interest that include each of the idealized microfluidic bifurcations having a well with a coating
Microfluidic chips comprising symmetric and asymmetric bifurcations or bifurcations with same and different cross-sectional areas
the microfluidic chip comprises a symmetric idealized microfluidic bifurcation and an asymmetric idealized microfluidic bifurcation, or comprises an idealized microfluidic bifurcation fluidly coupled with daughter channels with the same cross-sectional areas and an idealized microfluidic bifurcation fluidly coupled with daughter channels with different cross-sectional areas
Arrangements in parallel or as an idealized microfluidic network with single inlet and outlet
the plurality of idealized microfluidic bifurcations are arranged in parallel and are in fluid communication with a single inlet; or the plurality of idealized microfluidic bifurcations and idealized microfluidic junctions form an idealized microfluidic network with the inlet in fluid communication with the parent channel of a first bifurcation and the outlet in fluid communication with the parent channel of a final junction
Non-duplication of angles among bifurcations
the angles formed between the two or more daughter channels and the parent channel are not duplicated within the plurality of idealized microfluidic bifurcations
Non-duplication of ratios of cross-sectional areas among bifurcations
the ratios of the cross-sectional areas of the two or more daughter channels for each of the plurality of idealized microfluidic bifurcations is not duplicated
Designs with neither angles nor cross-sectional area ratios duplicated
neither the angles formed between the daughter channels and the parent channel nor the ratios of the cross-sectional areas of the two or more daughter channels are duplicated
Interactions selected from adhesion to cells, adhesion to protein, and uptake by cells
the one or more interactions between the particles and the coating of the plurality of idealized microfluidic bifurcations is selected from the group consisting of: particle adhesion to cells of the coating, particle adhesion to protein of the coating, particle uptake by cells of the coating, and combinations thereof
The independent claims cover in-vitro methods using idealized microfluidic bifurcations (single and plural) and microfluidic chips with specified channel dimensions and daughter channel angles, coated walls and defined locations of interest, designs including symmetric/asymmetric and non-duplicated geometries, and methods to measure, determine and correlate particle distributions and interactions with coatings, including specified particle types and interaction categories.
Stated Advantages
PDMS offers the advantages of gas permeability beneficial for cell culture, optical transparency, ease of casting, and producing small volume, inexpensive, disposable chips.
Very thin PDMS constructs can be successfully used for long-term cell culture and cellular assays on microfluidic chips.
By bonding the polymer microchannel onto a custom glass bottom laid out in the appropriate form, microfluidic chips may be formed onto standard 24 or 96 well plates, providing for scale-up and high-throughput screening.
Interactions of particles at synthetic bifurcations are predictive of and correlate with particle interactions in physiological bifurcations, enabling simple, idealized bifurcations, junctions, and combinations thereof to be used to screen for particle and cell adhesion at corresponding structures in biological microvascular networks.
Documented Applications
In-vitro method for characterizing one or more interactions of particles with one or more microfluidic bifurcations and/or junctions.
In-vitro assay method for quantifying one or more interactions between particles and one or more microfluidic bifurcations and/or junctions.
In-vitro method for screening particles for one or more interactions with one or more microfluidic bifurcations and/or junctions.
Screening particles and cells for the presence of desired or absence of undesirable interactions with the surfaces of biological microvascular structures such as bifurcations and junctions.
Adhesion assays on channels coated with proteins to yield shear-adhesion maps.
Adhesion assays on channels coated with cultured cells to yield shear-adhesion maps.
Particle uptake studies on channels coated with cultured cells to determine percentage of cells with uptaken particles at specified locations.
Formation of microfluidic chips bonded onto glass bottoms compatible with standard 24 or 96 well plates for scale-up and high-throughput screening.
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