Silicone-based bioscaffolds for cellular therapies.

Cellular therapy, whereby cells are transplanted to replace or repair damaged tissues and/or cells, is now becoming a viable therapeutic option to treat many human diseases. Silicones, such as polydimethylsiloxane (PDMS), consist of a biocompatible, inert, non-degradable synthetic polymer, characterized by the presence of a silicon‑oxygen‑silicon (Si-O-Si) linkage in the backbone. Silicones have been commonly used in several biomedical applications such as soft tissue implants, microfluidic devices, heart valves and 3D bioscaffolds. Silicone macroporous bioscaffolds can be made with open, interconnected pores which can house cells and facilitate the formation of a dense vascular network inside the bioscaffold to aid in its engraftment and integration into the host tissue. In this review, we will present various synthesis/fabrication techniques for silicone-based bioscaffolds and will discuss their assets and potential drawbacks. Furthermore, since cell attachment onto the surface of silicones can be limited due to their intrinsic high hydrophobicity, we will also discuss different techniques of surface modification. Finally, we will examine the physical (i.e. density, porosity, pore interconnectivity, wettability, elasticity, roughness); mechanical (tension, compression, hardness); and chemical (elemental composition-properties) properties of silicone bioscaffolds and how these can be modulated to suit the needs for specific applications.