Sulindac encapsulation and release from functional poly(HEMA) microparticles prepared in supercritical carbon dioxide

Revolutionizing Intervertebral Disc Regeneration: Advances and Future Directions in Three-Dimensional Bioprinting of Hydrogel Scaffolds

Hydrogels are multifunctional platforms. Through reasonable structure and function design, they use material engineering to adjust their physical and chemical properties, such as pore size, microstructure, degradability, stimulus-response characteristics, etc. and have a variety of biomedical applications. Hydrogel three-dimensional (3D) printing has emerged as a promising technique for the precise deposition of cell-laden biomaterials, enabling the fabrication of intricate 3D structures such as artificial vertebrae and intervertebral discs (IVDs). Despite being in the early stages, 3D printing techniques have shown great potential in the field of regenerative medicine for the fabrication of various transplantable tissues within the human body. Currently, the utilization of engineered hydrogels as carriers or scaffolds for treating intervertebral disc degeneration (IVDD) presents numerous challenges. However, it remains an indispensable multifunctional manufacturing technology that is imperative in addressing the escalating issue of IVDD. Moreover, it holds the potential to serve as a micron-scale platform for a diverse range of applications. This review primarily concentrates on emerging treatment strategies for IVDD, providing an in-depth analysis of their merits and drawbacks, as well as the challenges that need to be addressed. Furthermore, it extensively explores the biological properties of hydrogels and various nanoscale biomaterial inks, compares different prevalent manufacturing processes utilized in 3D printing, and thoroughly examines the potential clinical applications and prospects of integrating 3D printing technology with hydrogels.

Silicone Resin Coating of Micro-Sized Ferrite Particles Using Supercritical Carbon Dioxide

An environmentally friendly and efficient polymer coating method for micro-sized particles was developed using supercritical CO₂. Because this method used supercritical CO₂ as the solvent to dissolve the coating material, we avoided environmental pollution from organic solvents, saved the energy required to evaporate/remove organic solvents, realized a uniform coating film on the fine particles, and prevented agglomeration of the coating particles. The solubilities of the five silicone resins used as coating materials were measured using the flow method, and the data were well correlated by Chrastil’s equation with an average deviation of 5.7%. Resins comprising numerous methyl-group side chains exhibited high solubilities and were suitable coating materials. A new semi-flow-type coating method using supercritical CO₂ was also developed, which deposited a film with a uniform thickness of 0.2–1.3 μm on whole fine particles. Notably, in this method, the film thickness was easily controlled. A simple and rapid technique was developed for measuring the coating thickness using X-ray fluorescence analysis. The model for calculating the coating film thickness was based on the material balance of the coating material. This model satisfactorily predicted the thickness with an average error of 0.085 μm by measuring the solubility of the coating material in supercritical CO₂, integrated flow volume of supercritical CO₂, particle diameter, density and charged weight of the fine particle, and coating material density.