Mini/microfiber : from fabrication to water collection and biomedical applications

Abstract

Mini/microfibers are of increasing interest because of their wide applications in many fields, including sensor, microfluidics and biomedical engineering. In this work, we concentrate on the fabrication of versatile mini/microfibers and their applications in water collection and vascular engineering. The present work contains two parts: bioinspired microfibers for water collection and mini/microfibers for vascular engineering.

For bioinspired microfibers for water collection, we develop a gas-in-water microfluidic method to precisely fabricate well-controlled versatile microfibers with cavity knots (named cavity-microfiber), like tiny-cavity-microfiber, hybrid-cavity-microfiber, cavity-microfiber and chained microfiber, which demonstrate tunable morphologies, unique surface properties, assembling ability, flexibility, cytocompatibility and hydroscopicity. Cavity-microfibers are assembled into 3D scaffolds for culturing the human umbilical vein endothelial cells (HUVECs) and dehumidifying. The HUVECs on the scaffolds demonstrate good cell viability, confirming the good cytocompatibility of cavity-microfibers. And the cavity-microfibers and their scaffolds also demonstrate excellent dehumidifying ability and large-scale dehumidifying, respectively.

Moreover, due to the design of cavity as well as polymer composition, the cavity-microfiber is endowed with unique surface roughness, mechanical strength and long-term durability, thus enabling a unique performance of water collection. The maximum water volume collected on a single knot is almost 495 times than that of the knot. Moreover, the spider-web-like networks assembled by cavity-microfibers demonstrate excellent large-scale water collection. Our light-weighted yet tough, low-cost microfibers offers promising opportunities for biomedical engineering, dehumidifying and large-scale water collection.

For mini/microfibers for vascular engineering, firstly, we develop one-step co-axial spinning approach to fabricate well-controlled hollow fibers rapidly and precisely for artificial blood vessels. The hollow fibers are endowed with unique mechanical properties, liquid-transport ability, permeability and cytocompatibility, thus enabling the required performance as artificial blood vessel. The well-defined blood-vessel-like lumens are also constructed by fine embeddedness of the HUVECs on the interior surface of hollow fiber to reproduce the physiological environment of human blood vessels.

We also develop inhalable templated method to fabricate well-controlled PDMS hollow fibers with tunable dimensions, unique mechanical properties, perfusable ability and cytocompatibility precisely for elastomeric perfusable blood vessels. And the blood-vessel-like lumens through seeding the HUVECs on the interior surface of PDMS hollow fibers are also presented, closely reproducing the physiological environment of human blood vessels.

Finally, we develop microfiber-patterned method to precisely fabricate versatile well-controlled 3D perfusable vascular networks with cylindrical channels. This method can rapidly generate cylindrical-channel chips with 1D, 2D, 3D and multilayered structures, enabling the independent and precise control over the vascular geometry. These chips are endowed with unique perfusable ability and cytocompatibility, enabling the required performance for vascular networks. The inner surfaces of vascular network are easily lined with the HUVECs to biomimic the endothelialization of human blood vessel. The results show the HUVECs attach well on the inner surface of channels and form endothelial tubular lumens with great cell viability.

In a word, we develop the simple, low-cost and effective techniques for the fabrication of versatile mini/microfibers for water collection and vascular engineering. Our techniques and mini/microfibers offer plenty of promising opportunities for dehumidifying, water collection, drug development, biomaterials and tissue engineering.