Endothelialized microfluidics for studying microvascular interactions in hematologic diseases.

Advances in microfabrication techniques have enabled the production of inexpensive and reproducible microfluidic systems for conducting biological and biochemical experiments at the micro- and nanoscales (1,2). In addition, microfluidics have also been specifically used to quantitatively analyze hematologic and microvascular processes, because of their ability to easily control the dynamic fluidic environment and biological conditions(3-6). As such, researchers have more recently used microfluidic systems to study blood cell deformability, blood cell aggregation, microvascular blood flow, and blood cell-endothelial cell interactions(6-13).However, these microfluidic systems either did not include cultured endothelial cells or were larger than the sizescale relevant to microvascular pathologic processes. A microfluidic platform with cultured endothelial cells that accurately recapitulates the cellular, physical, and hemodynamic environment of the microcirculation is needed to further our understanding of the underlying biophysical pathophysiology of hematologic diseases that involve the microvasculature. Here, we report a method to create an "endothelialized" in vitro model of the microvasculature, using a simple, single mask microfabrication process in conjunction with standard endothelial cell culture techniques, to study pathologic biophysical microvascular interactions that occur in hematologic disease. This "microvasculature-on-a-chip" provides the researcher with a robust assay that tightly controls biological as well as biophysical conditions and is operated using a standard syringe pump and brightfield/fluorescence microscopy. Parameters such as microcirculatory hemodynamic conditions, endothelial cell type, blood cell type(s) and concentration(s), drug/inhibitory concentration etc., can all be easily controlled. As such, our microsystem provides a method to quantitatively investigate disease processes in which microvascular flow is impaired due to alterations in cell adhesion, aggregation, and deformability, a capability unavailable with existing assays.

[1]  Daniel A Fletcher,et al.  Analyzing cell mechanics in hematologic diseases with microfluidic biophysical flow cytometry. , 2008, Lab on a chip.

[2]  Kapil Pant,et al.  Microfluidic devices for modeling cell-cell and particle-cell interactions in the microvasculature. , 2011, Microvascular research.

[3]  L Mahadevan,et al.  Sickle cell vasoocclusion and rescue in a microfluidic device , 2007, Proceedings of the National Academy of Sciences.

[4]  Dana M Spence,et al.  The dual nature of extracellular ATP as a concentration-dependent platelet P2X1 agonist and antagonist. , 2009, Integrative biology : quantitative biosciences from nano to macro.

[5]  Arnan Mitchell,et al.  A shear gradient–dependent platelet aggregation mechanism drives thrombus formation , 2009, Nature Medicine.

[6]  Kapil Pant,et al.  A physiologically realistic in vitro model of microvascular networks , 2009, Biomedical microdevices.

[7]  T. Quiroga,et al.  The level of laboratory testing required for diagnosis or exclusion of a platelet function disorder using platelet aggregation and secretion assays. , 2009, Seminars in thrombosis and hemostasis.

[8]  W. Murphy,et al.  Haemolytic uraemic syndrome: prognostic factors. , 2000, Clinical and laboratory haematology.

[9]  Craig A Simmons,et al.  Macro- and microscale fluid flow systems for endothelial cell biology. , 2010, Lab on a chip.

[10]  D. Beebe,et al.  Fundamentals of microfluidic cell culture in controlled microenvironments. , 2010, Chemical Society reviews.

[11]  I. Vermes,et al.  Microfluidic Technology in Vascular Research , 2009, Journal of biomedicine & biotechnology.

[12]  Daniel T Chiu,et al.  A microfluidic model for single-cell capillary obstruction by Plasmodium falciparum-infected erythrocytes , 2003, Proceedings of the National Academy of Sciences of the United States of America.

[13]  J. Moake,et al.  In vitro modeling of the microvascular occlusion and thrombosis that occur in hematologic diseases using microfluidic technology. , 2012, The Journal of clinical investigation.

[14]  Ahmad S. Khalil,et al.  Functional endothelialized microvascular networks with circular cross-sections in a tissue culture substrate , 2010, Biomedical microdevices.

[15]  Mehmet Toner,et al.  Clinical Microfluidics for Neutrophil Genomics and Proteomics , 2010, Nature Medicine.

[16]  N. Stanietsky,et al.  The interaction of TIGIT with PVR and PVRL2 inhibits human NK cell cytotoxicity , 2009, Proceedings of the National Academy of Sciences.