Dr. Thomas F. Keller "Self-Organisation of Macromolecules and Biomacromolecules at Interfaces"
Institute of Materials Science and Technology (IMT), Friedrich-Schiller-University Jena
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When |
Jan 16, 2013 from 02:15 PM to 03:00 PM |
Where | FRIAS Hörsaal, Albertstr. 19, Freiburg |
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A nanoscale interfacial design plays a key role for the development of new materials in the biomedical field. Within seconds to minutes after implantation of artificial devices into the human body nanoscale proteins adsorb on the implant surface. Their surface-induced arrangement controls the subsequent biological response, such as blood coagulation or inflammation reactions.
Molecular self-assembled surfaces may help to develop a more fundamental understanding on how the interfacial nanostructure as, e.g., crystallinity, nanoscale chemical functionality and building blocks of the implant material can control the structure and organisation of adsorbed biomacromolecular layers.
In this context, melt drawing of thin polymer films is introduced as a technique to generate ultraflat, highly oriented nanostructured model surfaces of the biomedical relevant ultrahigh molecular weight Polyethylene (UHMWPE). Also a substrate-based method employing crystallization and phase separation of extended chain Polyethylene-b-Polyethylenoxide (PE-b-PEO) co-oligomers is discussed that permits to create heterogeneous surface nanostructures with lateral dimensions of ~ 10 nm.
Atomic force microscopy suggests that the surface nanostructure of melt drawn UHMWPE films induces a dense packed, ordered layer of the protein fibrinogen that plays a key role in the surface-induced blood coagulation cascade. At the same time the nanostructure impedes the formation of protein networks. The existence of such an ordered fibrinogen layer is substantiated by the anisotropic dynamic properties of single fluorescence-labelled fibrinogen molecules during adsorption, as monitored by tracking single molecule trajectories.
The understanding of such biomacromolecular adsorption processes may in the future serve as basis for a nanoscale design of biomaterials surfaces with tailored biological response.
References:
ACS NANO 5 (2011) 3120-3131.
Advanced Functional Materials 22 (2012) 2617–2623.
Macromolecules 45 (2012) 4740–4748.