Abstract: A microfluidic device for increasing convective clearance of particles from a fluid is provided. A network of first channels can be separated from a network of second channels by a first membrane. The network of first channels can also be separated from a network of third channels by a second membrane. Fluid containing an analyte can be introduced in the network of first channels. Infusate can be introduced into the network of second channels, and waste-collecting fluid can be introduced into the network of third channels. A pressure gradient can be applied in a direction perpendicular to the direction of fluid flow in the network of first channels, such that the analyte is transported from the network of first channels into the network of third channels through the second membrane.

Abstract: A multi-lumen catheter includes a primary lumen having a proximal end and a tip and a secondary lumen parallel to the primary lumen. The primary lumen and the secondary lumen share a wall. A port is defined in the wall proximate the tip of the primary lumen and provides fluidic communication between the primary lumen and the secondary lumen.

Abstract: An instrument port for introducing instruments into a surgical site, including a port body having a channel running therethrough from a proximal end to a distal end, an instrument sleeve in slidable contact with the channel, creating a gap therebetween, and fluid flow for removing emboli efficiently from the instrument port, wherein the fluid flow includes the gap is provided. A fluid flow system for use in an instrument port is provided. A method of removably securing an instrument sleeve to a port body by anchoring the instrument port to heart tissue, making at least one flood line in a channel, flushing out emboli, and performing surgery with the instrument port.

Abstract: A catheter includes an elongated tube having a distal end and a proximal end. The elongated tube includes porous material having an interior and an exterior face. The interior face defines a lumen along a central axis of the elongated tube. The porous material is configured to flow a fluid between the interior face and the exterior face and to seep the fluid out of the porous material through the exterior face and interior face. A lining covers at least a portion of the exterior face and substantially limits perfusion through the exterior face at the portion of the exterior face covered by the lining. The catheter is impregnated with a material that prevents buildup of material on one of an inner face or an outer face of the catheter or the lining is coated with one or more of an anticoagulant, antibiotic, or antithrombotic.

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.

Abstract: A microfluidic device for increasing convective clearance of particles from a fluid is provided. A network of first channels can be separated from a network of second channels by a first membrane. The network of first channels can also be separated from a network of third channels by a second membrane. Fluid containing an analyte can be introduced in the network of first channels. Infusate can be introduced into the network of second channels, and waste-collecting fluid can be introduced into the network of third channels. A pressure gradient can be applied in a direction perpendicular to the direction of fluid flow in the network of first channels, such that the analyte is transported from the network of first channels into the network of third channels through the second membrane.

Abstract: A microfluidic device for increasing convective clearance of particles from a fluid is provided. A network of first channels can be separated from a network of second channels by a first membrane. The network of first channels can also be separated from a network of third channels by a second membrane. Fluid containing an analyte can be introduced in the network of first channels. Infusate can be introduced into the network of second channels, and waste-collecting fluid can be introduced into the network of third channels. A pressure gradient can be applied in a direction perpendicular to the direction of fluid flow in the network of first channels, such that the analyte is transported from the network of first channels into the network of third channels through the second membrane.

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.

Abstract: An compact hydraulic manifold for transporting shear sensitive fluids is provided. A channel network can include a trunk and branch architecture coupled to a bifurcation architecture. Features such as tapered channel walls, curvatures and angles of channels, and zones of low fluid pressure can be used to reduce the size while maintaining wall shear rates within a narrow range. A hydraulic manifold can be coupled to a series of microfluidic layers to construct a compact microfluidic device.

Abstract: A compact hydraulic manifold for transporting shear sensitive fluids is provided. A channel network can include a trunk and branch architecture coupled to a bifurcation architecture. Features such as tapered channel walls, curvatures and angles of channels, and zones of low fluid pressure can be used to reduce the size while maintaining wall shear rates within a narrow range. A hydraulic manifold can be coupled to a series of microfluidic layers to construct a compact microfluidic device.

Abstract: A multi-lumen catheter includes a primary lumen having a proximal end and a tip and a secondary lumen parallel to the primary lumen. The primary lumen and the secondary lumen share a wall. A port is defined in the wall proximate the tip of the primary lumen and provides fluidic communication between the primary lumen and the secondary lumen.

Abstract: A catheter includes an elongated tube having a distal end and a proximal end. The elongated tube includes porous material having an interior and an exterior face. The interior face defines a lumen along a central axis of the elongated tube. The porous material is configured to flow a fluid between the interior face and the exterior face and to seep the fluid out of the porous material through the exterior face and interior face. A lining covers at least a portion of the exterior face and substantially limits perfusion through the exterior face at the portion of the exterior face covered by the lining. The catheter is impregnated with a material that prevents buildup of material on one of an inner face or an outer face of the catheter or the lining is coated with one or more of an anticoagulant, antibiotic, or antithrombotic.

Abstract: A microfluidic device for increasing convective clearance of particles from a fluid is provided. A network of first channels can be separated from a network of second channels by a first membrane. The network of first channels can also be separated from a network of third channels by a second membrane. Fluid containing an analyte can be introduced in the network of first channels. Infusate can be introduced into the network of second channels, and waste-collecting fluid can be introduced into the network of third channels. A pressure gradient can be applied in a direction perpendicular to the direction of fluid flow in the network of first channels, such that the analyte is transported from the network of first channels into the network of third channels through the second membrane.

Abstract: The present disclosure describes systems and methods for mimicking body tissue and the function thereof. The mimicked body tissue can include kidney tissue, the blood brain barrier, and other tissues. In some implementations, the systems described herein are used to test the impact of controlled factors on the tissue. The controlled factors can include flow rates, shear rates, and test chemicals (e.g., therapeutics and toxins). In some implementations, the system and methods are used to test pharmaceutical and biological therapies, characterize healthy or diseased tissue, and observe phenomena of the tissue in vitro.

Abstract: The device and methods described herein relate to a seeping flow catheter. The seeping flow catheter includes a porous material. The inner face of the porous material defines the lumen of the catheter. The porous material is configured such that fluid can flow along the length of the catheter, between the inner face and outer face of the porous material. As the fluid flows through the porous material, the fluid can seep into the lumen of the catheter through the inner face or out of the catheter through the outer face of the porous material. Portions of the inner or outer face can include a lining that substantial reduces the perfusion of the fluid through the lined areas.

Abstract: The instrument ports for introducing instruments into a surgical site that are disclosed herein include a port body having a channel running therethrough from a proximal end to a distal end, an instrument sleeve in slidable contact with the channel, creating a gap therebetween, and a fluid flow element for removing emboli efficiently from the instrument port, wherein the fluid flow element includes the gap. Disclosed fluid flow systems are for use in the disclosed instrument ports. Methods are also disclosed for removably securing an instrument sleeve to a port body by anchoring the instrument port to heart tissue, making at least one flood line in a channel, flushing out emboli, and performing surgery with the instrument port.

Abstract: A microfluidic device is provided. A manifold having a first channel, a second channel, and a third channel configured to transport blood can be coupled to a substrate defining an artificial vasculature. The first channel can be configured to carry blood in a first direction. Each of the second and third channels can couple to the first channel at a first junction and can be configured to receive blood from the first channel. The second channel can be configured to carry blood in a second direction away from the first direction. The third channel can be configured to carry blood in a third direction away from the second direction. The first, second, and third channels can be non-coplanar.

Abstract: An compact hydraulic manifold for transporting shear sensitive fluids is provided. A channel network can include a trunk and branch architecture coupled to a bifurcation architecture. Features such as tapered channel walls, curvatures and angles of channels, and zones of low fluid pressure can be used to reduce the size while maintaining wall shear rates within a narrow range. A hydraulic manifold can be coupled to a series of microfluidic layers to construct a compact microfluidic device.

Abstract: An compact hydraulic manifold for transporting shear sensitive fluids is provided. A channel network can include a trunk and branch architecture coupled to a bifurcation architecture. Features such as tapered channel walls, curvatures and angles of channels, and zones of low fluid pressure can be used to reduce the size while maintaining wall shear rates within a narrow range. A hydraulic manifold can be coupled to a series of microfluidic layers to construct a compact microfluidic device.

Abstract: The device and methods described herein relate to a seeping flow catheter. The seeping flow catheter includes a porous material. The inner face of the porous material defines the lumen of the catheter. The porous material is configured such that fluid can flow along the length of the catheter, between the inner face and outer face of the porous material. As the fluid flows through the porous material, the fluid can seep into the lumen of the catheter through the inner face or out of the catheter through the outer face of the porous material. Portions of the inner or outer face can include a lining that substantial reduces the perfusion of the fluid through the lined areas.