Systems and methods for increasing convective clearance of undesired particles in a microfluidic device
Inventors
Charest, Joseph L. • Nohilly, Martin • DiBiasio, Christopher • Borenstein, Jeffrey T. • Laurenzi, Mark • Wilson, Jonathan
Assignees
Charles Stark Draper Laboratory Inc • Johnson and Johnson Innovation LLC
Publication Number
US-10603419-B2
Publication Date
2020-03-31
Expiration Date
2033-01-11
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Abstract
A microfluidic device for increasing convective clearance of particles from a fluid is provided. In some implementations, described herein the microfluidic device includes multiple layers that each define infusate, blood, and filtrate channels. Each of the channels have a pressure profile. The device can also include one or more pressure control features. The pressure control feature controls a difference between the pressure profiles along a length of the device. For example, the pressure control feature can control the difference between the pressure profile of the filtrate channel and the pressure profile of the blood channel. In some implementations, the pressure control feature controls the pressure difference between two channels such that the difference varies along the length of the channels by less than 50% of the pressure difference between the channels at the channels' inlets.
Core Innovation
The invention provides a microfluidic device designed to increase convective clearance of particles from fluids such as blood by utilizing multiple layers that define infusate, blood, and filtrate channels. Each channel has an associated pressure profile, and the device incorporates pressure control features to manage differences between these profiles along the device length. Notably, the pressure control feature can regulate the pressure difference so that the variation along the length is less than 50% of the pressure difference at the inlets, enabling more efficient convective clearance while maintaining safe conditions.
The invention addresses the problem present in conventional dialysis devices where uneven pressure gradients and fluid volume profiles along length of channels cause varying hematocrit levels, which can be unsafe, and limit convective clearance efficiency. Traditional devices require larger size or increased flow rates to improve clearance, leading to complications. This microfluidic device aims to maintain a substantially constant hematocrit throughout the blood channel by controlling pressure profiles and flow through pressure control features that actively or passively manage the pressure differentials to ensure safe, uniform fluid dynamics.
Claims Coverage
The patent includes one independent claim presenting eight main inventive features relating to the structure and control of the microfluidic device and its channels.
Layered channel structure with defined pressure profiles
A microfluidic device comprising three layers defining infusate, blood, and filtrate channels each having distinct pressure profiles with controllable slopes.
Interchannel flow barriers with fluid passage openings
A first interchannel flow barrier separating infusate and blood channels, comprising openings allowing fluid passage, and a second barrier separating filtrate and blood channels.
Active control of filtrate channel pressure slope
A first controllable flow control device configured to actively control the slope of the filtrate channel pressure profile relative to the blood channel.
Active control of infusate channel pressure slope
A second controllable flow control device to actively control the slope of the infusate channel pressure profile relative to the blood channel.
Control system for maintaining parallel pressure slopes
A control system configured to modify states of the first and second flow control devices to keep infusate and filtrate pressure profiles substantially parallel along the channel length.
Sensor-responsive control of flow control devices
The device further comprises one or more pressure sensors linked to the control system, enabling modification of flow control devices responsive to sensor output.
Configurable channel dimensions and membrane features
Blood channel dimensions range from about 50 to 500 µm in height, 50 to 900 µm in width, and 3 to 30 cm in length; interchannel flow barriers may be membranes or sterility barriers; the infusate barrier may comprise non-porous regions with defined apertures.
Multiple blood channels and sequential fluid communication
The second layer may define multiple blood channels fluidically linked to the infusate channel through sequential openings along the flow path, with spacing and size of openings variable along the length.
The claims cover a multi-layer microfluidic device with controllable pressure profiles in infusate, blood, and filtrate channels, equipped with flow control devices and a control system to maintain desired pressure relationships, supported by sensor feedback and specific structural features to optimize convective clearance and safe operation.
Stated Advantages
Increased convective clearance of solutes within a compact dialysis device without needing increased channel length or blood flow.
Maintenance of substantially constant hematocrit levels throughout the blood channel to preserve blood safety and health during treatment.
Controlled transmembrane pressure profiles along channel length prevent membrane damage and fouling, improving device reliability and durability.
Efficient use of membrane surface by enabling substantially uniform pressure differences, maximizing convective clearance across the entire membrane length.
Active control features and feedback sensors allow for precise regulation of pressure profiles to maintain safe and effective operating conditions.
Documented Applications
Hemofiltration devices for filtering blood to remove urea, uric acid, creatinine, and other waste molecules or undesired particles.
Dialysis systems employing microfluidic convective clearance devices with multi-layer channels for blood cleansing.
Devices for extracorporeal treatment maintaining blood health by controlling hematocrit and shear conditions in microfluidic channels.
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