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Updated: Mar 10, 2026
A Microphysiological System to Study Leukocyte-Endothelial Cell Interaction during Inflammation
Published on: December 9, 2021
3D ECM-inflammation model on a microfluidic chip for neutrophil transmigration from whole blood investigations
Shide Bakhtiari1, Vanessa Velasco1, Ronald W Davis1
1Stanford Genome Technology Center (SGTC), Stanford University, Palo Alto, CA 94304, USA. shide68@stanford.edu.
Insights
A novel microfluidic chip isolates neutrophils from whole blood using a 3D extracellular matrix, improving inflammation studies. Platelet count significantly influences neutrophil migration, offering new insights into inflammation resolution and disease treatments.
Area of Science:
- Biomedical Engineering
- Cell Biology
- Immunology
Background:
- Neutrophils are crucial in inflammation but traditional in vitro assays lack physiological relevance.
- Existing methods require pre-processing and use 2D migration analysis, limiting in vivo simulation.
- Extracellular matrices are vital for neutrophil activation and deformation during migration.
Purpose of the Study:
- To develop a microfluidic platform for direct neutrophil isolation from whole blood.
- To mimic in vivo inflammation events using a 3D extracellular matrix.
- To investigate factors influencing neutrophil migration and transmigration.
Main Methods:
- Created a microfluidic chip incorporating a 3D extracellular matrix for direct neutrophil isolation.
- Optimized collagen, chemoattractant, and blood concentrations for maximal neutrophil yield.
- Performed regression analysis to correlate blood component quantities with neutrophil isolation.
Main Results:
- Achieved 30-70 neutrophils/mm² with 100% viability and purity from whole blood.
- Identified platelet count as a significant factor in neutrophil transmigration (R²=0.88).
- Demonstrated a non-linear relationship between platelet count and transmigrated neutrophils.
Conclusions:
- The microfluidic platform effectively isolates neutrophils from whole blood, enhancing in vitro inflammation models.
- Platelets play a key role in neutrophil migration dynamics during inflammation.
- This platform offers improved understanding of neutrophil behavior in inflammation, disease, and therapeutic interventions.
Abstract:
Neutrophils have been linked to several inflammation diseases. To study the role of neutrophils in inflammation diseases and conditions, in vitro inflammation assays have been developed. Two drawbacks of these assays include the reliance on pre-processing techniques to isolate neutrophils and 2D migration analysis. These assays limit the physiological relevance of in vivo neutrophil migration which involves other blood components and the transmigration of 3D extracellular matrix-tissue environments. Extracellular matrices regulate neutrophil activation and deformation - important factors in the study of neutrophil migration behavior. To address these limitations, we have successfully created a microfluidic chip that recreates an inflammation event and directly isolates neutrophils from a small volume of whole blood using a 3D extracellular matrix. We optimized our platform by adjusting the extracellular matrix collagen, chemoattractant, and blood concentrations to maximize neutrophil yield. Six individual blood samples showed a range of 30-70 isolated neutrophils per mm2 from whole blood with 100% viability and purity using 2 mg mL-1 extracellular matrix collagen and 150 nM fMLP concentrations. Using this preliminary data, we performed a regression analysis to examine the effect of blood component quantities - white blood cells, red blood cells, neutrophils, and platelets - on the number of isolated neutrophils. The regression analysis revealed that the number of platelets possibly affects the number of transmigrated neutrophils conforming to a non-linear second-degree polynomial function, with an R2 of 0.88. Our findings highlight the potential of our platform to facilitate and improve the understanding of neutrophil migration and invasion in inflammation resolution, diseases, and treatments.
