Biomedical engineering Graduate Students Seminar
Biomedical Engineering Graduate Seminar
Shari Yosinski (Mark Reed)
Title: "Electrokinetic Manipulation of Biological Particles for Improved Biosensing"
Abstract: The ability to isolate and detect biomarkers of interest at low concentrations is important for early disease diagnosis, toxin detection, and understanding cellular communication at the single-cell level. The application of electric fields to particles in solution can induce particle movement via dielectrophoretic force on the particle as well as electroosmotic force on the ions in solution. Application of this type of electric field enables particles to be isolated and concentrated without labels or chemical tethers. Increasing the effective local concentration of a biomarker of interest can decreases the effective limit of detection of a sensing system. By employing micro- and nano-fabrication techniques, devices have been made to manipulate bio-particles whose size spans four orders of magnitude. Manipulation of large immune cells, red blood cells, bacteria, exosomes, DNA constructs, antibodies and small molecules all offer a unique way to improve different biosensing platforms and, for the case of exosomes, possibly enable detailed studies of single-cell exosome communications for the first time.
Amogh Sivarapatna (Laura Niklason)
Title: "Vascular Tissue Regeneration Using Human iPSC-Derived Endothelial Cells"
Abstract: Vascular endothelial cells (ECs) are highly plastic in nature and hemodynamic fluid flow is a crucial regulator of arterio-venous fate determination. Organ-specific ECs exist in different microenvironments in vivo under different chemical and mechanical conditions. ECs can be derived from human induced pluripotent stem cells (hiPSC-ECs) using a step-wise differentiation protocol and are unique in that they have never been exposed to blood flow. We sought to generate highly pure ECs from hiPSCs and specify an arterial-like fate using shear stress. We cultured hiPSC-ECs for 24 hours in a biomimetic flow bioreactor to demonstrate activation of Notch signaling, upregulation of several arterial markers including EphrinB2 and Conexin40 as well as anti-thrombotic and anti-inflammatory markers KLF2 and KLF4. Furthermore, the exogenous addition of soluble factors was not able to fully recapitulate this phenotype that was imparted by shear stress exposure. Thus, we are able to use shear stress to modulate and specify the phenotype of hiPSC-ECs to enrich for a vasoprotective, arterial-like subtype, which is amenable to vascular tissue engineering applications. We have also started optimizing a more clinically-relevant, serum and growth factor-free differentiation protocol to obtain hiPSC-ECs in 5 days as well as extending this work to a microvascular setting.
When: Thursday, October 22, 2015
Where: Becton Seminar Room
Time: 4PM