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Biocoating of Implants with Mediator Molecules: Surface Enhancement of Metals by Treatment with Chromosulfuric Acid
Author(s) -
Jennissen H. P.,
Zumbrink T.,
Chatzinikolaidou M.,
Steppuhn J.
Publication year - 1999
Publication title -
materialwissenschaft und werkstofftechnik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.285
H-Index - 38
eISSN - 1521-4052
pISSN - 0933-5137
DOI - 10.1002/(sici)1521-4052(199912)30:12<838::aid-mawe838>3.0.co;2-w
Subject(s) - mediator , molecule , materials science , nanotechnology , surface modification , chemistry , chemical engineering , engineering , organic chemistry , medicine
Abstract Proteins such as the model protein 125 I‐ubiquitin and recombinant human bone morphogenetic protein 2 ( 125 I‐rhBMP‐2) were covalently immobilized on titanium surfaces after reaction of the latter with aminopropyltriethoxysilane (APS) and activation with carbonyldiimidazole (CDI). On titanium powder (grain size ∼ 60 μm, 2400 cm 2 /g) net amounts of 15–60 ng/cm 2 of 125 I‐ubiquitin could be coupled after correction for ca. 25% non‐specifically adsorbed protein. Similarly, normal polished and special surface‐enhanced titanium and stainless steel plates (size 1 × 10 × 15 mm) were modified as above and coupled with 125 I‐ubiquitin and 125 I‐BMP‐2. The surface‐enhanced metal plates were prepared by a special chromosulfuric acid treatment, probably leading to an etching of the metal surface and to an increase in the thickness of the metal oxide layer, which produced a strong enhancement of the binding capacity for chemical modification reactions. Dynamic contact angle measurements (Wilhelmy) of the clean surface‐enhanced plates yielded an advancing contact angle of 18.0 ° and zero contact angle hysteresis. On such surface‐enhanced titanium plates net amounts of 300–500 ng/cm 2 of 125 I‐ubiquitin could be immobilized, values 2–5 fold higher than obtained on normal polished plates. In comparison 60–100 ng/cm 2 125 I‐rhBMP‐2 could be immobilized on the oxidized plates. The above technique is being applied as a tool for biocoating bone implants with the aim of constructing bone‐cell‐reactive interfaces with specific biorecognition properties.