Platelet activation and fibrinogen presentation on polyetherurethane surfaces containing fluorinated surface-modifying macromolecules
By: by Tania M. Massa.
Published: 2006
Language: eng
Number of pages: 199
ISBN-13: 9780494157428
Description: Surface-modifying macromolecules (SMMs) are fluorinated oligomers that are immiscible in polyurethanes and migrate to the surface of polyurethane blends, forming a hydrophobic surface that minimizes non-specific biological interactions. Three different SMMs (PPO212L, PTMO212F and PTMO212I) were used to surface modify a polyetherurethane (Base PU) and were shown to reduce the number of adherent platelets in previously reported work. However, higher levels of platelet activation were observed on the Base PU and PTMO212I surfaces as measured by scanning electron microscopy and image analysis. In the current thesis, it was hypothesized that the nature of platelet activating proteins, such as fibrinogen, was modulated on these surfaces. Therefore, the nature of the adsorbed fibrinogen (Fg) was investigated to explain the platelet response. The quantity of adsorbed Fg measured from buffer, human plasma and reconstituted whole blood could not account for the platelet number because protein adsorption yielded similar Fg levels on all surfaces. The Fg distribution and platelet activation were highly correlated at larger platelet aggregate ranges. The Fg antibody detection showed that the presentation of the Fg molecule, represented by conformation, orientation and molecule packing, drives platelet response (attachment and activation). More specifically, the data highlight the domain "communication" within the Fg molecule, which responds to different surfaces, and directs platelet response. Upon AFM analysis of hydrated surfaces, it was found that the PPO212L and PTMO212F materials had a well-mixed phase structure and the lowest platelet adhesion, platelet activation, Fg aggregate size and antibody detection. Conversely, Base PU and PTMO212I materials had isolated phases (large rounded vs. striated, respectively) and had higher platelet activation, Fg aggregates and antibody detection. The conclusion was that SMMs could be formulated to modulate Fg in a manner that reduced platelet activation in blood contacting PUs.
Notes: Source: Dissertation Abstracts International, Volume: 67-06, Section: B, page: 3270.

Thesis (Ph.D.)--University of Toronto, 2006.

Includes bibliographic references.

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