Advances in Barrier Membranes for Guided Bone Regeneration Techniques

Guided bone regeneration (GBR) is a widely used technique for alveolar bone augmentation. Among all the principal elements, barrier membrane is recognized as the key to the success of GBR. Ideal barrier membrane should have satisfactory biological and mechanical properties. According to their composition, barrier membranes can be divided into polymer membranes and non-polymer membranes. Polymer barrier membranes have become a research hotspot not only because they can control the physical and chemical characteristics of the membranes by regulating the synthesis conditions but also because their prices are relatively low. Still now the bone augment effect of barrier membrane used in clinical practice is more dependent on the body’s own growth potential and the osteogenic effect is difficult to predict. Therefore, scholars have carried out many researches to explore new barrier membranes in order to improve the success rate of bone enhancement. The aim of this study is to collect and compare recent studies on optimizing barrier membranes. The characteristics and research progress of different types of barrier membranes were also discussed in detail.

A comprehensive review of electrospinning block copolymers

Electrospinning provides a versatile and cost-effective route for the generation of continuous nanofibres with high surface area-to-volume ratio from various polymers. In parallel, block copolymers (BCPs) are promising candidates for many diverse applications, where nanoscale operation is exploited, owing to their intrinsic self-assembling behaviour at these length scales. Judicious combination of BCPs (with their ability to make nanosized domains at equilibrium) and electrospinning (with its ability to create nano- and microsized fibres and particles) allows one to create BCPs with high surface area-to-volume ratio to deliver higher efficiency or efficacy in their given application. Here, we give a comprehensive overview of the wide range of reports on BCP electrospinning with focus placed on the use of molecular design alongside control over specific electrospinning type and post-treatment methodologies to control the properties of the resultant fibrous materials. Particular attention is paid to the applications of these materials, most notably, their use as biomaterials, separation membranes, sensors, and electronic materials.

Development of keratin-based membranes for potential use in skin repair

The layers in skin determine its protective and hemostasis functions. This layered microstructure cannot be naturally regenerated after severe burns; we aim to reconstruct it using guided tissue regeneration (GTR). In GTR, a membrane is used to regulate tissue growth by stopping fast-proliferating cells and allowing slower cells to migrate and reconstruct specialized microstructures. Here, we proposed the use of keratin membranes crosslinked via dityrosine bonding. Variables from the crosslinking process were grouped within an energy density (ED) parameter to manufacture and evaluate the membranes. Sol fraction, spectrographs, and thermograms were used to quantify the non-linear relation between ED and the resulting crosslinking degree (CD). Mechanical and swelling properties increased until an ED threshold was reached; at higher ED, the CD and properties of the membranes remained invariable indicating that all possible dityrosine bonds were formed. Transport assays showed that the membranes allow molecular diffusion; low ED membranes retain solutes within their structure while the high ED samples allow higher transport rates indicating that uncrosslinked proteins can be responsible of reducing transport. This was confirmed with lower transport of adipogenic growth factors to stem cells when using low ED membranes; high ED samples resulted in increased production of intracellular lipids. Overall, we can engineer keratin membranes with specific CD, a valuable tool to tune microstructural and transport properties.