Jongwon Kim

Surface Fixation of Lumbrokinase via Photochemical Reaction of Azidophenyl Group

A new method for the immobilization of lumbrokinase (LK) on polymer was developed. The method is based on the photochemical reaction of the azidophenyl group, which produces a highly reactive phenylnitrene upon ultraviolet (UV) light irradiation. First, an aminated polymer, partially derivatized with a photoreactive phenyl azido group in its side chains, was coated onto a polyurethane (PU) surface. Subsequently, the surface was exposed to UV light. To induce the carboxyl group on the UV-light-treated surface, poly(methyl vinyl ether-co-maleic acid) (MAcMEC) was reacted. LK was immobilized on the PU surface using l-ethyl-3-(3-dimethylaminopropyl)carbo-diimide (EDC) in aqueous solvent. Electron spectroscopy for chemical analysis (ESCA) and water contact angle measurement before and after sequential surface reactions revealed that LK was immobilized successfully. The LK immobilized on the PU surface had fibrinolytic activity. In conclusion, LK immobilization via this photochemical reaction will be useful in improving the blood compatibility of blood-contacting polymer.

Anatomical Fitting Simulators (AFS) for Totally Implantable Artificial Heart Design

The development of the orthotopically positioned totally implantable artificial heart (TAH) requires knowledge of the detailed structure of the thoracic cavity and the relative position of remnants to guide the design of the blood pump system. To adjust anatomical fit, a three-dimensional anatomical fitting simulator (AFS) for the TAH was developed with three-dimensional image reconstruction of magnetic resonance imaging (MRI) and a computer-aided design (CAD) system. The wire-frame model of the spatial geometry of the aortic arch and pulmonary bifurcation was extracted from electrocardiogram (ECG)-gated MR images of the human chest. A solid model of the Korean TAH with adjustable inlet/outlet ports including atrial cuffs and arterial graft, was generated with a MicroStation (Intergraph, Huntsville, AL, USA) CAD system. The chest cavity model and TAH model were integrated in the AFS to select the accurate position and direction of the inlet/outlet port of the implantable TAH. The orthotopic position of the implantable TAH, the direction and curvature of arterial grafts, and the diameter and inflow direction of atrial cuffs in the final TAH design were confirmed with the AFS. The newly developed AFS offers a versatile method for the development of the implantable TAH.