In this study, the mechanical and tribological properties of polymethyl methacrylate (PMMA)-based dentures strengthened by a low content of alumina (Al2O3) nanoparticles were evaluated. PMMA nanocomposites with different weight fractions (0.2, 0.4, 0.6, 0.8, and 1 wt%) of Al2O3 were fabricated, and a sample of pure PMMA was used as a control. Compression, hardness, and wear tests were conducted to investigate the effect of a low Al2O3 filler content on the mechanical and tribological properties of PMMA. The addition of Al2O3 filler improved the mechanical and tribological characteristics of PMMA. The highest elastic modulus and compressive yield strength (3.56 GPa and 138.21 MPa, respectively) were obtained using the PMMA sample with 0.6 wt% of nanoalumina, which represent an increase of 20.27% and 14.7%, respectively, compared with those of the pure PMMA. The fracture toughness and hardness were improved with the increase in the filler content until it reached 0.8 and 1.00 wt%, respectively. The tribological characteristics of PMMA also improved with the addition of Al2O3 nanoparticles. The least coefficient of friction (COF) and wear rate were obtained at a filler content of 0.6 wt%. Therefore, the addition of low amounts of Al2O3 to PMMA-based resins can improve their mechanical and tribological properties such as hardness, elastic modulus, fracture toughness, COF, and wear resistance.

Three-dimensional (3D) microfluidic channels, which simulate human tissues such as blood vessels, are useful in surgical simulator models for evaluating surgical devices and training novice surgeons. However, animal models and current artificial models do not sufficiently mimic the anatomical and mechanical properties of human tissues. Therefore, we established a novel fabrication method to fabricate an eye model for use as a surgical simulator. For the glaucoma surgery task, the eye model consists of a sclera with a clear cornea; a 3D microchannel with a width of 200–500 µm, representing the Schlemm’s canal (SC); and a thin membrane with a thickness of 40–132 µm, representing the trabecular meshwork (TM). The sclera model with a clear cornea and SC was fabricated by 3D molding. Blow molding was used to fabricate the TM to cover the inner surface of the sclera part. Soft materials with controllable mechanical behaviors were used to fabricate the sclera and TM parts to mimic the mechanical properties of human tissues. Additionally, to simulate the surgery with constraints similar to those in a real operation, the eye model was installed on a skull platform. Therefore, in this paper, we propose an integration method for fabricating an eye model that has a 3D microchannel representing the SC and a membrane representing the TM, to develop a glaucoma model for training novice surgeons.

Bionic microscopic vessel models can contribute to the development of vascular treatment skills and techniques for clinical training. Most microscopic vessel models are limited to two dimensions, but three-dimensional (3D) models are important for surgery, such as on retina microscopic vessels, for the observation of colon microvessels, for measuring the deformability of red blood cell (RBC), and so on. Therefore, bionic 3D blood vessel models are increasingly in demand. For this reason, it is necessary to establish 3D fabrication techniques for microchannels. In this study, we established two fabrication methods for 3D microfluidic devices for the development of microscopic vessel models. First, we employed an exposure method using photolithographic technology. Second, we employed a 3D method using femtosecond laser and mask hybrid exposure (FMEx). Both methods made it possible to fabricate a millimeter-scale 3D structure with a submicrometer resolution and achieve an easy injection of solution. This is because it was possible to fabricate typical microfluidic channels used for model inlet and outlet ports. Furthermore, in the FMEx method, we employed an acid-diffusion effect using a chemically amplified resist to form a circular channel cross-section. The acid-diffusion effect made it realizable to fabricate a smooth surface independent of the laser scanning line width. Thus, we succeeded in establishing two methods for the fabrication of bionic 3D microfluidic devices with microfluidic channels having diameters of 15–16 µm for mimicking capillary vessels.