Silicon Micropore‐Based Parallel Plate Membrane Oxygenator

Abstract

Extracorporeal membrane oxygenation (ECMO) is a life support system that circulates the blood through an oxygenating system to temporarily (days to months) support heart or lung function during cardiopulmonary failure until organ recovery or replacement. Currently, the need for high levels of systemic anticoagulation and the risk for bleeding are main drawbacks of ECMO that can be addressed with a redesigned ECMO system. Our lab has developed an approach using microelectromechanical systems (MEMS) fabrication techniques to create novel gas exchange membranes consisting of a rigid silicon micropore membrane (SμM) support structure bonded to a thin film of gas-permeable polydimethylsiloxane (PDMS). This study details the fabrication process to create silicon membranes with highly uniform micropores that have a high level of pattern fidelity. The oxygen transport across these membranes was tested in a simple water-based bench-top set-up as well in a porcine in vivo model. It was determined that the mass transfer coefficient for the system using SµM-PDMS membranes was 3.03 ± 0.42 mL O min m cm Hg with pure water and 1.71 ± 1.03 mL O min m cm Hg with blood. An analytic model to predict gas transport was developed using data from the bench-top experiments and validated with in vivo testing. This was a proof of concept study showing adequate oxygen transport across a parallel plate SµM-PDMS membrane when used as a membrane oxygenator. This work establishes the tools and the equipoise to develop future generations of silicon micropore membrane oxygenators.

Advances in extracorporeal membrane oxygenator design for artificial placenta technology

“…Recently, some efforts have focused on improving the structural integrity of microfluidic devices. G, Dabaghi et al 136 uses a steel mesh to add rigidity to their PDMS membranes, and (H) Dharia et al 139 presents a device featuring rigid silicon micropore membranes bonded to a 5 µm PDMS layer. Images reproduced with permission from respective cited publications [Color figure can be viewed at wileyonlinelibrary.com]…”

“…Another approach taken by Dharia and colleagues at UCSF used composite micropore-containing silicon and PDMS membranes. 139 The composite membranes offer the advantage of providing a rigid, yet, thin structure that can be readily stacked into a parallel plate configuration. Importantly, the parallel plate design allows optimization of the blood flow path to minimize shear stresses and stagnancy.…”

Artificial Organs 2018: A Year in Review

“…Ajay Dharia et al of the University of California, San Francisco, CA, USA, reported on a silicon micropore‐based parallel plate oxygenator design. Their proof of concept study show adequate oxygen transport.…”

Toward Development of a Higher Flow Rate Hemocompatible Biomimetic Microfluidic Blood Oxygenator

“…The emergence of microfluidics technology presents an enormous opportunity to address many of the fundamental challenges in ECMO, due to the ability of microfluidics to fashion gas transfer membranes thinner than hollow fiber membrane oxygenators (HFMO), shallower blood channels, and potentially to better recapitulate the smooth and gentle manner in which blood flows through small vessels in the lung during the physiological gas transfer process [ 17 , 18 , 19 ]. Over the past decade, tremendous progress has been made by a number of groups in the development of microfluidic oxygenators, leveraging advances in computational designs, microfabrication techniques, and biomaterials technologies toward prototype devices that have been tested in vitro and in vivo in a large number of proof of concept studies [ 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 ].…”