Biocompatible Artificial Tendril with Spontaneous 3D Janus Multi-helix-perversion Configuration
A helical perversion as a singularity structure is widely seen in nature, such as climbing plant tendril, which is referred to as a kinked state connecting two helices with opposite chirality. Although previous macroscale elastic bistrip systems have been used to fabricate multiple helix-perversion structures, it is still challenging to obtain the multi-perversions in microscale. Herein, we have for the first time discovered an interesting phenomenon when PCL microcoils are assembled on PEO/PCL microstems using wet, side-by-side electrospinning which combines side-by-side electrospinning with a coaugulation bath collection. Such side-by-side electrospun Janus microfibers, upon the mismatch strain between the two jets in the coaugulation bath, are transformed into 3D multi-helix-perversion microstructures through self-scrolling. On the 3D multi-helix-perversion microstructures, the growth of HUVECs (human umbilical vein endothelial cells) are observed with a preferential cell distribution of around 86 % on the PCL microcoils. Simultaneously higher focal adhesion, enhanced cell proliferation and elongation are also exhibited on the PCL microcoils, leading to a distinctive 3D Janus cellular pattern. . Such novel 3D multi-helix-perversion microstructures hold great potential in 3D Janus biomaterials for adjustable cell patterning.