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Fused deposition modeling (FDM) and melt electrowriting (MEW) are techniques that use polymer fibers as building blocks for printing complex 3D structures, with fibers at the macroscopic and micrometer scale. Here, FDM and MEW are used to produce fibers of shape memory polymer at two different scales, and compare the performance of these fibers, in terms of shape fixity, shape recovery, and self‐healing properties. FDM and MEW are used for 4D printing of a shape memory polymer blend of thermoplastic poly(ε‐caprolactone) (30% by wt.) and a soft thermoplastic elastomer polyurethane (70% by wt.) at two different scales. The shape transformation from a programmed temporary state to the printed permanent shape in response to temperature as the stimuli imparts the 4D aspect to the printing. The mean fiber diameter of shape memory polymer produced by FDM and MEW is 340 and 40 µm, respectively. The manufactured fibers show an excellent shape fixity ratio (≈95%) and shape recovery properties (>84%). MEW fibers show a 1.5x faster recovery rate than FDM fibers due to the scaling effect. The excellent shape memory properties are complemented by self‐healing characteristics in the printed fibers. Additionally, MEW of a shape memory polymer is directly performed on a cylindrical collector to obtain tubular constructs which can potentially be used as stents for coronary or vascular applications. [ABSTRACT FROM AUTHOR]

In vitro skin models are validated methods for screening cosmetics and pharmaceuticals, but still have limitations. The bilayer poly(ε‐caprolactone) scaffold/membrane model described here overcomes some of these deficits by integrating a solution electrospun (SES) membrane at the dermoepidermal interface and a melt electrowritten (MEW) scaffold that provides an optimal open‐pore environment for the dermis. To the knowledge, this scaffold/membrane model is the only one capable of creating a properly differentiated, full thickness skin model with neosynthesized extracellular matrix (ECM) in only 18 days. Both the wavy and straight fiber scaffold designs create a well‐organized dermis, but dermal collagen organization differs between designs. Adding cells and vitamin C to the scaffolds improves the mechanical properties to more closely mimic native human skin. These findings establish bicomponent scaffolds as a promising advancement for rapidly creating different skin models with varied properties. The versatility and adaptability of the described model can be used for studying how the biological and physical microenvironment impact skin, and testing dermo‐cosmetics and pharmaceutical treatments on different ages of skin. Furthermore, it can be an excellent new tool for studying wound healing and development into its use as a graft or wound dressing is ongoing. [ABSTRACT FROM AUTHOR]