Seminar Announcement, 09/01/2015
Levich Institute Seminar Announcement, 09/01/2015
Tuesday, 09/01/2015
2:00 PM
Steinman Hall, Room #312
(Chemical Engineering Conference Room)

Professor Maria Santore
University of Massachusetts
Polymer Science and Engineering

"Controlling Dynamic Motion Signatures and Adhesion of Flowing Particles and Cells"


Particle capture from flow is a common phenomena, occurring in varied situations from the fouling of water treatment membranes to sensors and high-fidelity cancer diagnostics. A particularly interesting mechanism of particle capture occurs with white blood cells in their response to infection an injury. Leukocytes flowing in the bloodstream must adhere to the walls of venules prior to entering affected tissues. The process of deceleration and arrest occurs through a receptor-mediated rolling process that slows the cell motion so that firmly-binding receptors with slow binding kinetics are able to adhere to the cells. In this context, we examine the adhesive capture of flowing silica particles on a variety of engineered surfaces: Surfaces with polyethylene glycol brushes, resistant to bioadhesion but able to interact with silica through hydrogen bonding, are compared with cationic surfaces that adhere silica particles through electrostatic attractions. These materials are further benchmarked against collectors with nanometer-scale electrostatic heterogeneity. We observe that relatively uniform long range electrostatic attractions facilitate strong long range immediate particle arrest in flow while hydrogen bonding systems exhibit a more gradual particle capture with particle deceleration during rolling. Electrostatically heterogeneous surfaces are demonstrated to be able to facilitate sustained microparticle rolling for almost millimeter scale distances, with particle travel hundreds of times the particle diameter.


Interfacial polymer physics, dynamics, and colloidal phenomena: polymer and protein adsorption, biomaterial and biomimetic membranes, surface modification (polymer brushes, placement of functionalized surface clusters), adhesion and bioadhesion (of colloidal particles, bacteria, cells), coupling of interfacial forces with external fields. Applications include sensors, biomedical surfaces for implants and diagnostics, drug delivery vehicles, manipulation of colloidal stability, inks, paints, and coatings.

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