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en: Utilizing 2-(methacryloyloxy)ethyl choline hydrogen phosphate (MCHP) Coatings for Antibacterial Material on Ni-Ti Orthodontic Steel

en: 2025 International Advanced Technology and Taiwan-Japan Engineering Forum (IAT&TJEF)


en: Preparation of Platinum Nanoelectrodes Using Tapered Tungsten Probes and Their Application to a Single Cell Measurement

en: PRiME 2024 (Pacific rim meeting on electrochemisty and solid state science 2024) , Hawaii

en: Honolulu

ja: Honolulu

en: Platinum nanoelectrodes, which the electroactive region is located on the tip, were prepared in two steps. First, an insulating film was formed on the tapered tungsten probe by electrodeposition coating using the cationic electrodeposition paint, and then platinum nanopillars with a diameter of about 200 nm were formed on the tip using Focused-Ion-Beam Chemical-Vapor-Deposition (FIB-CVD). The conditions for forming an insulating film on tungsten surface with low thickness and excellent insulation properties were investigated and were evaluated by electrochemical measurements and SEM observations, and an appropriate insulating film was successfully produced. After the formation of a platinum pillar on the tip of an insulating film-coated tungsten probe, a platinum nanoelectrode was obtained and confirmed to function as an electrode. Using automatic micro manipulation system, repeated insertion of platinum nanoelectrode into HeLa cell was attempted. The results showed that the insertion of platinum nanoelectrodes into HeLa cells appeared to be successful.


en: Introducing Biocompatibility into Polypropylene Implant Devices Using 2-(Methacryloyloxy)ethyl Choline Hydrogen Phosphate Copolymers

en: International Conference on Advanced Materials Development and Performance 2024 (AMDP 2024)

en: Tokushima

ja: Tokushima

en: To improve the biocompatibility of hydrocarbon-based implanted materials, we conducted a study using a novel zwitterionic copolymer to modify the surface of polypropylene (PP) substrates. This modification aimed to decrease protein adsorption, a crucial initial phase of physiological reactions that significantly influences subsequent biological responses. 2-methacryloyloxyethyl phosphorylcholine (MPC) is widely used for medical device surface modification to prevent protein adsorption and platelet adhesion. In our previous research, we have synthesized 2-(methacryloyloxy)ethyl choline hydrogen phosphate (MCHP), in which the order of polar groups is reversed from that of MPC, and applied them to material surface modification. Unlike MPC, MCHP-modified surfaces maintained higher hydrophilicity even in acidic environments. Earlier studies demonstrated that block copolymers with controlled chain orientation, consisting of 70% n-butyl methacrylate (BMA) and 30% MPC units, provided water insoluble copolymers with excellent blood compatibility. To optimize the biocompatibility and stability of MCHP, we synthesized di-block copolymers with varying ratios of BMA and MCHP units and investigated the optimal synthesis conditions. In this study, MCHP and BMA block polymers were synthesized using the RAFT polymerization method. By controlling the polymerization time, we adjusted the chain lengths of MCHP and BMA and determined the monomer ratios in the polymers through molecular weight measurements. These block polymers were then used to modify PP substrates via hydrophobic interactions, and their modification stability and biocompatibility were evaluated. The experimental results revealed that a block polymer with a MCHP to BMA ratio of 2:8 provided high stability and biocompatibility on the modified surface. Compared to the optimal 3:7 ratio for MPC and BMA block polymers, MCHP required a longer hydrophobic chain to maintain stability due to its higher hydrophilicity. Nevertheless, the MCHP-modified surface retained biocompatibility with a shorter zwitterionic chain. In summary, our study demonstrates that MCHP-based block copolymers modification can effectively introduce the biocompatibility of PP substrates, providing a promising approach for improving the performance of implanted materials.