Biomedical Engineering Reference
In-Depth Information
10
Bioactive
CoatingsforImplantedDevices
SubbuVenkatraman,XiaYun,HuangYingying,DebasishMondal,andLiuKerhLin
CONTENTS
Introduction and Brief Historic Survey ................................................................................... 471
Bioactive Coatings Type 1: Controlled Bioactive Elution...................................................... 472
Applications ............................................................................................................................ 472
Cardiovascular Coating......................................................................................................... 472
Cardiovascular Stent Coatings ........................................................................................ 473
Other Stent Coatings and Bioactives .............................................................................. 475
Drug-Eluting Balloons ...................................................................................................... 477
Other Bioactive-Eluting Implants: Orthopedic Applications .......................................... 478
Bioactive Coatings II: Surface Modification for Cellular Interactions................................. 479
Platelet Interactions................................................................................................................ 480
Endothelialization of Biomaterial Surfaces ........................................................................ 482
Topological Modification ...................................................................................................... 483
Chemical Modification .......................................................................................................... 483
Micropatterning...................................................................................................................... 484
Status and Prognosis................................................................................................................... 485
References..................................................................................................................................... 485
IntroductionandBriefHistoricSurvey
One of the earliest successful bioactive coatings was that of a heparin-modified surface of a
polymer blood oxygenator component trademarked as Carmeda Affinity Blood Oxygenator
Trillium Affinity NT Blood Oxygenator, which received FDA approval in 1997. This bioac-
tive surface was based on a poly(ethylene oxide)-coupled heparin immobilization on a hol-
low porous membrane used as part of an oxygenator used in bypass surgery, for instance.
Since then, several types of heparin-modified surfaces have been introduced in various
devices, including chronic dialysis catheter (Bridges, 2007), stent coatings (Michael et al.,
2003), blood oxygenators (Okkema et al., 1991) as well as other components of the adult
perfusion circuit. The FDA Web site lists an extensive array of such devices. In our opin-
ion, heparin modification of surfaces is the most successful coating technology so far for
indwelling or implanted medical devices.
The other area of bioactive coating research involves hard-tissue implants, such as
an artificial hip or knee joint. Here, the issue is acceleration of healing to reduce immo-
bilization time for surgery patients. Thus, the role of the coating is to induce bone cell
attachment and proliferation on the implant surface. The first commercialization was a
471
