Mesoporous Silica and their Applications
Given that few biomaterials possess all the necessary characteristics to perform ideally, researchers have pursued the development of hybrid or composite biomaterials to synergize the beneficial properties of multiple materials into a superior matrix. In the context of regenerative dentistry, one strategy to promote the formation of healthy tissue involves the combination of natural and synthetic polymers with various other materials to enhance cellular interaction, encourage integration into host dental tissue, and provide tunable material properties and degradation kinetics . For instance, the addition of inorganic materials (e.g., bioceramic glasses) to a polymer scaffold has several advantages, including combining the osteoconductivity and bone-bonding potential of the inorganic phase with the porosity and interconnectivity of the 3D construct.
Jim Yang Lee Group - National University of Singapore
Porogen leaching, also known as solution casting/particulate leaching, has been a widely used and simple technique for the creation of porous scaffolds in tissue engineering. This method usually involves mixing water-soluble salt particles into a biodegradable polymer solution. The mixture is then cast into a mold of the desired shape. After the solvent is removed by evaporation or lyophilization, the salt particles are leached out to obtain a porous structure. This method has the advantages of simple operation and adequate control over pore size and porosity by the salt/polymer ratio and particle size of the added salt. Various porogens, including sodium chloride, sugar crystals, gelatin, and polymers, have been successfully used to fabricate porous structures . However, the wide variations of pore sizes, lack of interconnectivity, and irregular pore geometry have limited the use of this type of porogen in current tissue engineering applications. Further, the difficulty of removing soluble particles from the interior of a polymer matrix makes it difficult to fabricate very thick 3D scaffolds. Recently, different strategies have been used to address some of these issues. A new generation of porogen has been developed using the principles behind nucleation and crystallization science . Also, paraffin spheres have been used as pore-generating materials to create biodegradable polymer scaffolds with spherical pore shape and well-controlled interpore connectivity. These recent technologies provide a simple, convenient, more precise, and cost-effective method over traditional techniques of generating porous macrostructures.
Although the ideal 3D matrix materials for dental bone tissue engineering have yet to be developed, much progress has been made during the last few years. The requirements of scaffolds for dental bone tissue engineering are complex. A variety of characteristic parameters, such as the degradation rate, mechanical strength, porosity, pore size, pore microstructures, surface chemistry, hybridization with inorganic materials, and topography, should be carefully considered and controlled for the design and fabrication of scaffolds to meet the needs of this particular tissue engineering application. The development and fabrication techniques of novel biodegradable biomaterials and scaffolds with well-defined macrostructures reviewed will constitute a centerpiece of the research efforts in the field of regenerative medicine in dentistry. Using polymer scaffolding to controllably manipulate cell function and the spatiotemporal release of biologic therapeutics will likely enable development of new therapies and technologies for dental bone tissue repair and regeneration as well as other oral health applications.