Microfluidic organ assist device incorporating boundary layer disrupters
Inventors
Borenstein, Jeffrey T. • Charest, Joseph L. • DiBiasio, Chris • Finley, Violet
Assignees
Charles Stark Draper Laboratory Inc • Johnson and Johnson Innovation LLC
Publication Number
US-9597441-B2
Publication Date
2017-03-21
Expiration Date
2034-09-16
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Abstract
The general disclosure discusses a system and method for improving the efficacy of blood filtration treatments such as hemodialysis, hemofiltration, and hemodiafiltration. More particularly, the disclosure discusses a microfluidic device that includes first and second channels separated by a permeable membrane. One of the channels is configured for blood flow and includes a protein gel disruption layer. The protein gel disruption layer includes a plurality of elements at least partially extending across the blood flow channel that reduce the formation of a boundary layer or gel layer at the blood-membrane interface.
Core Innovation
The invention provides a microfluidic device designed to improve the efficacy of blood filtration treatments such as hemodialysis, hemofiltration, and hemodiafiltration. The device comprises first and second channels separated by a permeable membrane, where one channel is configured for blood flow and includes a protein gel disruption layer. This protein gel disruption layer consists of multiple elements that extend at least partially across the blood flow channel, designed to reduce the formation of a boundary layer or gel layer at the blood-membrane interface.
The problem addressed by this invention is the inefficiency and complications in current dialysis methods, which rely on extending treatment time or increasing flow rates that are inconvenient, expensive, and potentially harmful to patient safety and quality of life. Protein and solute accumulation on membranes during blood filtration leads to boundary or gel layers that hamper material transfer across the membrane, reducing device efficiency.
By incorporating the protein gel disruption layer, which includes elements such as screens, meshes, or topographical features integrated into or adjacent to the membrane, the microfluidic device disrupts the laminar flow near the blood-membrane interface. This disruption reduces or prevents the formation of protein gel layers, maintaining membrane permeability and improving mass transfer efficiency during treatment. The elements typically have a height of at least about 1 μm and terminate close to the membrane within a third of the height of the blood flow channel.
Claims Coverage
The patent claims include two independent claims, each describing a microfluidic blood filtration device with inventive features focusing on the structural and functional aspects of the protein gel disruption layer and channel configurations.
Protein gel disruption layer characteristics
A protein gel disruption layer adjacent to or positioned within a first channel configured for liquid (blood) flow, including a plurality of elements extending at least partially across the first channel. The elements have a height of at least about 1 μm and terminate at a distance from the center of the membrane thickness less than or equal to about one-third of the first channel height.
Channel and membrane configuration
The device includes a first layer defining a first channel and a second layer defining a second overlapping channel separated by a permeable membrane that allows passage of liquid.
Extended channel and membrane arrangement
Optionally, a third layer defining a third channel overlapping the first channel, separated by a second membrane from the first channel.
Full channel coverage by gel disruption elements
The elements of the protein gel disruption layer can extend fully across the first channel.
Gel disruption elements integrated into membrane
The elements of the gel disruption layer can be topographical features integrated into the membrane surface.
Composition and dimensions of protein gel disruption layer
The gel disruption layer can be a screen adjacent to the membrane with screen openings sized about 100 μm to 5 mm. The screen is made from materials such as biocompatible metals, polyester, or polyamide, with pitches between elements from about 100 μm to 5 mm and heights about 1 μm to 3 μm.
Channel dimensions and functional configuration
The first channel height can range between about 50 μm and 100 μm with lengths between about 5 cm and 30 cm, and is configured for blood flow, while the second channel is configured for infusate, dialysate, or oxygen flow.
Structural integration and positioning of elements
The elements of the protein gel disruption layer extend from the surface opposite the membrane toward the membrane and can be integral to the first polymer layer extending adjacent to the membrane.
Definition of fluid communication openings
The protein gel disruption layer includes a plurality of elements that define openings allowing fluid communication between the membrane and the first channel.
The independent claims protect a microfluidic blood filtration device featuring a protein gel disruption layer with specific dimensional and positional characteristics that extend across the blood flow channel and function to disrupt boundary or gel layer formation, thereby improving filtration efficiency. The claims also cover variations in channel layering, membrane arrangements, materials, and integration methods of the disruption elements.
Stated Advantages
Improves efficacy and performance of mass transfer through the membrane by preventing protein and solute buildup on the membrane surface.
Reduces formation of protein gel or boundary layers at the blood-membrane interface, maintaining filtration efficiency over time.
Enables minor controlled disturbances in laminar blood flow near the membrane to reduce gel layer formation without causing harmful effects to blood.
Allows maintenance of membrane permeability and treatment efficiency during hemodialysis, hemofiltration, and oxygenation applications.
Documented Applications
Hemodialysis treatment involving blood filtration and waste removal using dialysate fluid.
Hemofiltration and hemodiafiltration blood filtration treatments.
Oxygenation of partially deoxygenated blood through diffusion of oxygen from a gas channel into the blood channel.
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