Master Pieces of Valuable Authors VI
Organic-inorganic hybrid mesoporous organosilica has gained more attention in biomedicine due to its high surface area, mesoporous channels, functional framework, and high drug loading capacity. In this study, disulfide- bridged hybrid mesoporous organosilica nanoparticles (MONs) as nanocarriers were employed to construct a nanosystem (ICG/DOX-MONs@DNA20) for delivering drugs and photothermal agents, in which DNA molecules as “switches” were modified on the surface of MONs to control drug release. The results showed that the ICG/DOX-MONs@DNA20 nanosystem could increase the temperature to above 43 ℃ for photothermal therapy with near-infrared (NIR) laser irradiation. On the other hand, the ICG/DOX-MONs@DNA20 nanosystem exhibited a very slow release of DOX (12.3% in 6 h) at 37 ℃, but a rapid release of DOX (52.4% in 6 h) occurred at 43 ℃. Cell culture experiments indicated that the nanosystem can be internalized by HeLa cells, and exhibited an enhanced therapeutic efficacy of synergistic chemo- and photothermal therapy. Hence, the ICG/DOX-MONs@DNA20 nanosystem might be promising for synergistic chemo- and photo-thermal tumor therapy.
High-entropy ceramics, a novel class of single-phase ceramic solid solutions consisting of near-equimolar multielement species, are recently attracting tremendous attentions. Especially, the transition metal non-oxide high-entropy ceramics, such as transition metal carbide and boride high-entropy ceramics, have been proposed for potential applications in aerospace, nuclear energy, high-speed machining and many other extreme environments, owing to their excellent physical and chemical properties including super-high hardness, low thermal conductivity, good oxidation resistance and corrosion/erosion resistance. Recently, the research of high-entropy ceramics is only focused on composition design, fabrication methods, single-phase stability and mechanical properties, but the design criterion and theoretical analysis are rarely reported. Based on the researches of high-entropy alloy, the fabrication, characterization and theoretical study of several transition metal non-oxide high-entropy ceramics are summarized, along with some related results of high-entropy film. The prospects for the future developments of high-entropy ceramics are also discussed.
As for ceramic stereolithography technique, the preparation of suitable resin-based ceramic slurry is of primary importance. In this study, the effects of powder characteristics such as specific surface area, particle size and distribution, particle morphology on the rheological behavior of zirconia resin-based suspensions were investigated intensively. Results show that the specific surface area of the powder is the most important factor affecting slurry viscosity. Choosing low specific surface area and quasi-spherical shaped powder is more likely to obtain low viscosity slurries. In addition, the influence of solid loading on the flow behavior were also studied using Krieger-Dougherty model. Zirconia samples with the relative density of (97.83±0.33)% were obtained after sintering at 1550 ℃. No obvious abnormal grain growth in the microstructure of the sintered body is observed. Results indicate that after the optimization of the processing parameters with the help of rheology characterization, complex-shaped high-quality zirconia parts can be obtained using the stereolithography technique.
3D printed bioceramics derived from preceramic polymers are of great interest in bone tissue engineering due to their simplified fabrication processes. In this study, three-dimensional (3D) porous β-Ca2SiO4 scaffolds incorporated with ZrO2 were fabricated from silicone resin loaded with active CaCO3 and inert ZrO2 fillers by 3D printing. The fabricated scaffolds possessed uniform interconnected macropores with a high porosity (> 67%). The results showed that the increase of ZrO2 incorporation significantly enhanced the compressive strength, and stimulated cell proliferation and differentiation of osteoblasts. Importantly, the in vivo results indicated that the ZrO2-incorporated β-Ca2SiO4 scaffolds improved osteogenic capacity compared to pure β-Ca2SiO4 scaffolds. Taken together, the ZrO2-incorporated β-Ca2SiO4 scaffolds fabricated by combining polymer-derived strategy with 3D printing could be a promising candidate for bone tissue engineering.