ELECTROSPUN NANOFIBERS FOR TISSUE ENGINEERING

Tissue engineering is a relatively new fifield in biomedical engineering that is receiving much attention among the scientifific community and the general public. It is defifined as the biological alternative for harvested tissues, implants, and prostheses, and involves biomaterials, cell biology, biochemistry, biomedical engineering, and transplantation (Mooney and Mikos, 1999; Cima et al., 1991). Tissue engineering has the potential to solve the problem of donor tissues/organs and the limitations of current therapies in clinical tissue injury. The breadth of possibilities for creating replacement body parts includes the reconstitution of tissues (including tendon, vascular, nerve, bone, cartilage) and other organs (kidney, pancreas, liver) (Yang et al., 2001; Silver, 1994; Kim et al., 1994; Kim and Mooney, 1998; Bellamkonda et al., 1995). In tissue engineering, the living tissue cells from a human patient are extracted and expanded through cell culture in vitro, and then seeded onto the extracellular matrix (ECM) or scaffold, which guides the growth and proliferation of cells within the laboratory environment (Peters and Mooney, 1997).

The basis of tissue engineering can be represented by three basic components: cells, ECM biomimic (scaffold), and biologic signals (Bell, 2000). The scaffold is an important point in tissue engineering, including the preparation method and materials. The preparation approach determines the structure and mechanical properties of the scaffold; and the materials determine the biocompatibility, biodegradability, etc., of the scaffold.

Electrospinning is a well-known technique for fabricating nanoscale fifibers, which have been studied extensively because of their various advantages, such as high surface-to-volume ratio, tunable porosity, ease of surface functionalization, and ability to mimic the fifibrous structure of natural ECM in terms of scale and morphology (Wang et al., 2016; Hossain et al., 2013). Electrospun nanofifiber scaffolds provide a good microenvironment for cell adhesion,proliferation, and differentiation (Jiang et al., 2015). In tissue engineering applications, cells are cultured on the nanofifiber scaffold to prepare a cellbased scaffold and promote its bioactivity. Then the cell-based scaffold is used to enable the fabrication of functional tissues or organs, which can be used for reparative procedures in patients. As a promising treatment for tissue defects, in addition to mimicking the ECM structure and morphology, electrospun scaffolds must have good mechanical properties and biocompatibility. For example, the smallest structural units of tendons and ligaments are aligned collagen fifibrils, which range from 50 to 500 nm in diameter; tissue-engineered replacements should take into account the unique structure and mechanical functions of tendons and ligaments, which enable them to bear loads throughout complex joint loading regimes. As the main load-bearing tissue in our body, bone tissue-engineered scaffolds should have high compressive properties. However, there are some apparent discrepancies in the literature among the values of various mechanical properties for the different bone tissues, like jaw and radius. In conclusion, different tissues have different mechanical properties. This requires the tissue-engineered scaffolds to have mechanical properties that match those of normal tissues.

Paper link：https://www.sciencedirect.com/book/9780323512701/electrospinning-nanofabrication-and-applications