Multiscale polymeric fibers for drug delivery and tissue engineering

Owing to their superior capacity for building structures, polymeric fibers with diameters varying from a few nanometers to hundreds of microns have been explored in biomedical applications as drug carriers or tissue engineering scaffolds. Depending on the source materials, fabrication techniques, and post-treatments, both the fiber diameter and surface morphology, as well as mechanical features and the cell-fiber structure interactions can be thoroughly tuned. Although most techniques could produce fibers within a wide range of sizes, each type may have superior advantages in a certain range, which may highly relate to target biomedical fields. Therefore, to properly choose the optimal technique for specific fibers, a comprehensive review of the current fiber-producing techniques is indispensable. In the current review, several main fiber-producing techniques are summarized, compared, and discussed in detail regarding their dominant fiber size ranges, which were classified as nano (<1000 ​nm), micro (1 ​μm−100 μm) and macro (>100 ​μm). The principals, main parameters, and corresponding applications for each technique are reviewed, and the challenges and future perspectives are proposed. We believe this review is highly informative for novice researchers in this field.