Sepsis is an adverse systemic inflammatory response caused by microbial infection in blood. This paper reports a simple microfluidic approach for intrinsic, non-specific removal of both microbes and inflammatory cellular components (platelets and leukocytes) from whole blood, inspired by the invivo phenomenon of leukocyte margination. As blood flows through a narrow microchannel (20 × 20 µm), deformable red blood cells (RBCs) migrate axially to the channel centre, resulting in margination of other cell types (bacteria, platelets, and leukocytes) towards the channel sides. By using a simple cascaded channel design, the blood samples undergo a 2-stage bacteria removal in a single pass through the device, thereby allowing higher bacterial removal efficiency. As an application for sepsis treatment, we demonstrated separation of Escherichia coli and Saccharomyces cerevisiae spiked into whole blood, achieving high removal efficiencies of ∼80% and ∼90%, respectively. Inflammatory cellular components were also depleted by >80% in the filtered blood samples which could help to modulate the host inflammatory response and potentially serve as a blood cleansing method for sepsis treatment. The developed technique offers significant advantages including high throughput (∼1 ml/h per channel) and label-free separation which allows non-specific removal of any blood-borne pathogens (bacteria and fungi). The continuous processing and collection mode could potentially enable the return of filtered blood back to the patient directly, similar to a simple and complete dialysis circuit setup. Lastly, we designed and tested a larger filtration device consisting of 6 channels in parallel (∼6 ml/h) and obtained similar filtration performances. Further multiplexing is possible by increasing channel parallelization or device stacking to achieve higher throughput comparable to convectional blood dialysis systems used in clinical settings.
Confocal microscopy was performed at the W. M. Keck Biological Imaging Facility in Whitehead Institute. Financial support by the Singapore-MIT Alliance for Research and Technology (SMART) Centre (BioSyM IRG) is gratefully acknowledged. This work is also supported by the use of MIT’s Microsystems Technology Laboratories as well as the financial support by DARPA DLT (Dialysis-Like Therapeutics) program, under SSC Pacific grant N66001-11-1-4182. Any opinions, findings, and conclusions or recommendations expressed in this publication are those of the authors and do not necessarily reflect the views of the DARPA. H.Y.G. acknowledges Agency for Science, Technology and Research (A*STAR) Singapore for the post-doctoral fellowship support.
II. MATERIALS AND METHODS
B. Cell culture
C. Sample preparation
D. Device characterization and analysis
E. Confocal imaging
A. Microfluidic design and separation principle
B. Device optimization and confocal analysis
C. Device characterization of the cascaded design
D. Whole blood analysis
E. High throughput multiplexing using parallel design
Data & Media loading...
Article metrics loading...
Full text loading...