TY  - JOUR
A1  - Degtyar, Elena
A1  - Harrington, Matthew J.
A1  - Politi, Yael
A1  - Fratzl, Peter
T1  - The mechanical role of metal ions in biogenic protein-based materials
JF  - Angewandte Chemie : a journal of the Gesellschaft Deutscher Chemiker ; International edition
N2  - Protein-metal interactions-traditionally regarded for roles in metabolic processes-are now known to enhance the performance of certain biogenic materials, influencing properties such as hardness, toughness, adhesion, and self-healing. Design principles elucidated through thorough study of such materials are yielding vital insights for the design of biomimetic metallopolymers with industrial and biomedical applications. Recent advances in the understanding of the biological structure-function relationships are highlighted here with a specific focus on materials such as arthropod biting parts, mussel byssal threads, and sandcastle worm cement.
KW  - adhesives
KW  - biomaterials
KW  - metal coordination
KW  - sacrificial bonds
KW  - self-healing materials
Y1  - 2014
U6  - https://doi.org/10.1002/anie.201404272
SN  - 1433-7851
SN  - 1521-3773
VL  - 53
IS  - 45
SP  - 12026
EP  - 12044
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Braune, Steffen
A1  - Walter, M.
A1  - Schulze, F.
A1  - Lendlein, Andreas
A1  - Jung, Friedrich
T1  - Changes in platelet morphology and function during 24 hours of storage
JF  - Clinical hemorheology and microcirculation : blood flow and vessels
N2  - For in vitro studies assessing the interaction of platelets with implant materials, common and standardized protocols for the preparation of platelet rich plasma (PRP) are lacking, which may lead to non-matching results due to the diversity of applied protocols. Particularly, the aging of platelets during prolonged preparation and storage times is discussed to lead to an underestimation of the material thrombogenicity. Here, we study the influence of whole blood-and PRP-storage times on changes in platelet morphology and function.
 Whole blood PFA100 closure times increased after stimulation with collagen/ADP and collagen/epinephrine. Twenty four hours after blood collection, both parameters were prolonged pathologically above the upper limit of the reference range. Numbers of circulating platelets, measured in PRP, decreased after four hours, but no longer after twenty four hours. Mean platelet volumes (MPV) and platelet large cell ratios (P-LCR, 12 fL - 40 fL) decreased over time. Immediately after blood collection, no debris or platelet aggregates could be visualized microscopically. After four hours, first debris and very small aggregates occurred. After 24 hours, platelet aggregates and also debris progressively increased. In accordance to this, the CASY system revealed an increase of platelet aggregates (up to 90 mu m diameter)with increasing storage time.
 The percentage of CD62P positive platelets and PF4 increased significantly with storage time in resting PRP. When soluble ADP was added to stored PRP samples, the number of activatable platelets decreased significantly over storage time. The present study reveals the importance of a consequent standardization in the preparation of WB and PRP. Platelet morphology and function, particularly platelet reactivity to adherent or soluble agonists in their surrounding milieu, changed rapidly outside the vascular system. This knowledge is of crucial interest, particularly in the field of biomaterial development for cardiovascular applications, and may help to define common standards in the in vitro hemocompatibility testing of biomaterials.
KW  - Platelet
KW  - platelet function
KW  - platelet rich plasma
KW  - whole blood
KW  - platelet aging
KW  - platelet storage
KW  - hemocompatibility
KW  - biomaterials
Y1  - 2014
U6  - https://doi.org/10.3233/CH-141876
SN  - 1386-0291
SN  - 1875-8622
VL  - 58
IS  - 1
SP  - 159
EP  - 170
PB  - IOS Press
CY  - Amsterdam
ER  -