The Effects of a Zirconia Addition on the Compressive Strength of Reticulated Porous Zirconia-Toughened Alumina

Porous ceramics have attracted researchers due to their high chemical and thermal stability. Among various types of porous ceramics, reticulated porous ceramics have both high porosity and good permeability. These properties of porous ceramics are difficult to replace with porous metals and polymers. ZTA is used in a variety of applications, and a wealth of experimental data has already been collected. However, research reports on reticulated porous zirconia-toughened alumina (ZTA) are insufficient. Therefore, we prepared reticulated porous ZTA via the replica template method. In this study, various processing conditions (average particle size, zirconia content, solid loading, dispersant, and thickener) were adjusted to improve the compressive strength of the reticulated porous ZTA. As a result, the optimized processing conditions for improving the compressive strength of reticulated porous ZTA could be determined.

Effect of the Sintering Temperature on the Compressive Strengths of Reticulated Porous Zirconia

Porous ceramics have separation/collection (open pore) and heat-shielding/sound-absorbing (closed pore) characteristics not found in conventional dense ceramics, increasing their industrial importance along with dense ceramics. Reticulated porous ceramics, a type of porous ceramic material, are characterized by a three-dimensional network structure having high porosity and permeability. Although there have been numerous studies of porous zirconia, which is already widely used, there are insufficient reports on reticulated porous zirconia, and it is still challenging to improve the compressive strength of reticulated porous ceramics thus far, especially considering that too few studies have been published on this topic. Therefore, we prepared reticulated porous zirconia specimens using the replica template method. In this study, the compressive strength outcomes of reticulated porous zirconia were analyzed by controlling the PPI value (25, 45, 60, and 80 PPI) of the sacrificial polymer template, the average zirconia particle size (as-received, coarse, intermediate, and fine), and the sintering temperature (1400, 1500, and 1600 °C). Consequently, we confirm that it is possible to prepare reticulated porous zirconia with a wide range of strengths (0.16~1.26 MPa) as needed with an average particle size and while properly controlling the sintering temperature.

Porous Zirconia/Magnesia Ceramics Support Osteogenic Potential In Vitro

Porous zirconia (ZrO2), magnesia (MgO) and zirconia/magnesia (ZrO2/MgO) ceramics were synthesised by sintering and designated as ZrO2(100), ZrO2(75)MgO(25), ZrO2(50)MgO(50), ZrO2(25)MgO(75), MgO(100) based on their composition. The ceramic samples were characterised by means of scanning electron microscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy and atomic absorption spectrometry to explore the incorporation of Mg atoms into the zirconia lattice. The resulting porosity of the samples was calculated based on the composition and density. The final porosity of the cylinder-shaped ceramic samples ranged between 30 and 37%. The mechanical analysis exhibited that the Young modulus increased and the microstress decreased with increasing magnesia amount, with values ranging from 175 GPa for zirconia to 301 GPa for magnesia. The adhesion, viability, proliferation and osteogenic activity of MC3T3-E1 pre-osteoblastic cells cultured on the zirconia/magnesia ceramics was found to increase, with the magnesia-containing ceramics exhibiting higher values of calcium mineralisation. The results from the mechanical analysis, the ALP activity, the calcium and collagen production demonstrate that the zirconia/magnesia ceramics possess robust osteoinductive capacity, therefore holding great potential for bone tissue engineering.

Purification of anti-glycoconjugate monoclonal antibodies using newly developed porous zirconia particles

Here, we describe porous zirconia particles (PZPs) optimized for the purification of immunoglobulins. PZPs, with a pore size of approximately 10 nm, were designed to specifically interact with antibodies via surface modification with a phosphate functional group. A simple PZP purification method based on precipitation enabled efficient purification of mouse anti-glycosphingolipid globoside/Gb4Cer monoclonal IgM (κ-light chains) from hybridoma culture supernatants. Over 99% of contaminating proteins were removed by the PZP purification process, and approximately 50% of the IgM was recovered in the purified fraction after eluting the PZP-adsorbed antibodies with 100 mM phosphate buffer. Other IgG3 and IgM monoclonal antibodies that react with Gb4Cer or α2,6-sialyl LacNAc-modified glycoproteins could also be purified using PZPs and elution buffer at concentrations of 100–500 mM. All of the purified antibodies retained their antigen reactivity and specificity, indicating that PZP purification does not affect antibody function. As PZP purification is also suitable for purification of IgM consisting of λ-light chains and IgG derived from other mammalian species, it is expected to be applied to the purification of a variety of antibodies, including anti-glycoconjugate IgMs.