Published papers

To synthesize hydrogenated amorphous carbon (a-C:H) films, filamentary dielectric discharge (FDBD) is used to improve their mechanical properties compared to the films synthesized by glow dielectric barrier discharge (GDBD), which is generally used for atmospheric pressure-plasma-enhanced chemical vapor deposition. The discharge form transitioned from GDBD to FDBD when the gap between the electrodes is increased from 1 to 4 mm. The hardness of the films increased from 3.7 to 11.9 GPa by using FDBD. The results indicate that hard a-C:H films can be synthesized at room temperature by atmospheric pressure using FDBD.

In this report, we experimentally investigated the blood hemofiltration capacity of a nanoporous dialysis membrane (poly(ether sulfone), PES) whose surface was modified with fluorine-doped diamond-like carbon(f-DLC). Surface modification of the nanoporous membrane without clogging the nanopores is challenging. In vitro experiments revealed that the modified membrane successfully exhibited water permeability of one-tenth of the untreated. In vivo experiments with ultra-small hemofiltration devices composed of f-DLC PES membranes using SD rats were also conducted for the first time. The results proved that the f-DLC coated PES membrane can be used for hemofiltration, which will extend the lifetime of microfluidics-based implantable artificial kidney.

Purpose: To describe the feasibility of lymphangiography and the visibility of the lymphatic system using post-lymphangiographic multidetector CT (MDCT) for preclinical lymphatic interventions in a rabbit model. Materials and Methods: Lymphangiography via the popliteal lymph node or vessel after surgical exposure was performed, using six healthy female Japanese White rabbits. Lipiodol was manually injected for lymphangiography. Post-lymphangiographic MDCT examinations were performed in all rabbits. The dataset images were subjected to image processing analysis utilizing the three-dimensional maximum intensity projection technique. Three reviewers evaluated the degree of depiction of the lymphatic system using a four-point visual score (1, poor; 2, fair; 3, good; 4, excellent). The distance between the body surface and cisterna chyli was measured on post-lymphangiographic MDCT axial image. Results: Lymphangiography was successfully performed in all rabbits. The popliteal lymph node was detectable in 90%. The visualization of lymphatic system via the popliteal node was achieved in 89%. Mean visual scores of > 3.0 were realized by the right femoral lymphatic vessel, left femoral lymphatic vessel, left iliac lymphatic vessel, left lumbar lymphatic trunks and cisterna chyli, whereas mean visual scores of < 3.0 were yielded by the right iliac lymphatic vessel, right lumbar lymphatic trunks and thoracic duct. The distance between the body surface and cisterna chyli on post-lymphangiographic MDCT axial images was 4.33 ± 0.14 cm. Conclusion: Lymphangiography is feasible, and the visibility of the lymphatic system on post-lymphangiographic MDCT in a rabbit model provides enough information for interventional radiologists to perform preclinical lymphatic interventions.

The existing first-generation drug-eluting stent (DES) has caused late and very late stent thrombosis related to incomplete stent endothelialization. Hence, biomaterials that possess sufficient anti-thrombogenicity and endothelialization with the controlled drug release system have been highly required. In this work, we have developed a newly designed drug-release platform composed of 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer, a non-thrombogenic polymer, and micropatterned hydrogenated amorphous carbon (a-C:H), a cell-compatible thin film. The platelet adhesion and the endothelial cell adhesion behavior on the micropatterned substrates were investigated in vitro. The results indicated that the micropatterned a-C:H/MPC polymer substrates effectively supported the human umbilical vein endothelial cell (HUVEC) proliferation, while suppressing the platelet adhesion. Interestingly, the HUVEC exhibited different shape and behavior by changing the island size of the micropatterned a-C:H. By introducing both a non-thrombogenic polymer and cell-compatible thin films through a simple patterning method, we demonstrated that the platform had the potential to be utilized as a base material for DES with cell controllability. Statement of significance: The current first-generation drug-eluting stents (DES) would cause late and very late stent thrombosis due to the incomplete endothelialization of the metal stent material. In this work, we have developed a new DES platform composed of a 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer micropatterned by hydrogenated amorphous carbon (a-C:H). Two types of differently micropatterned a-C:H stent surface were made. Our studies revealed that the micropatterned a-C:H/MPC polymer substrates could effectively enhance the endothelial cell (EC) proliferation, simultaneously suppressing the platelet adhesion, becoming a highly biocompatible material especially for indwelling devices including a drug-release device. The new drug-release platform could be utilized as a base material for cell-controllable coating on DES.

Diamond-like hydrocarbon (DLHC, a-C:H) films were synthesized under atmospheric pressure filamentary by dielectric discharge (FDBD) to improve their mechanical properties compared to the films synthesized by glow dielectric barrier discharge (GDBD). GDBD is generally used for atmospheric pressure-plasma-enhanced chemical vapour deposition. The discharge form transitioned from GDBD to FDBD by increasing the gap between electrodes from 1 to 4 mm. The hardness of the films increased from 3.7 to 11.9 GPa by using FDBD. The results indicate that hard DLHC films can be synthesized at room temperature and on a large area under atmospheric pressure using FDBD.