Bioinspired Helical Microfibers from Microfluidics

Abstract

Helical objects are among the most important and landmark structures in nature, and represent an emerging group of materials with unique spiral geometry; because of their enriched physical and chemical properties, they can have multiple functionalities. However, the fabrication of such complex helical materials at the micro- or nanoscale level remains a challenge. Here, a coaxial capillary microfluidic system, with the functions of consecutive spinning and spiraling, is presented for scalable generation of helical microfibers. The generation processes can be precisely tuned by adjusting the flow rates, and thus the length, diameter, and pitch of the helical microfibers are highly controllable. Varying the injection capillary design of the microfluidics enables the generation of helical microfibers with structures such as the novel Janus, triplex, core-shell, and even double-helix structures. The potential use of these helical microfibers is also explored for magnetically and thermodynamically triggered microsprings, as well as for a force indicator for contraction of cardiomyocytes. These indicate that such helical microfibers are highly versatile for different applications.

Surfaces Inspired by the Nepenthes Peristome for Unidirectional Liquid Transport

“…[6] Without energy input, these biological surfaces can harness the movement of water through their unique structural features and chemical composition, [11][12][13] which gives inspiration for designing and fabricating functional surfaces and materials with wide applications in fields including antifogging and fog-collection, [14][15][16] microfluidic devices, [17][18][19][20][21] lubrication, [22,23] and liquid transport. [24][25][26][27] One-dimensional materials for unidirectional liquid transport, inspired by spider silk and cactus spines, have attracted major research interest in the last few years.…”

Bioinspired Polymeric Helical and Superhelical Microfibers via Microfluidic Spinning

“…These methods often exhibited less control over the composition, λ, d , A and length of the helical fibers. Recently, substantial elegant achievements have been made in microfluidic spinning helical microfibers via liquid rope coiling effect within the microchannels . However, these helical microfibers were mainly restricted to the Ca‐alginate system due to its unique and rapid gelation/solidification process.…”

“…However, these helical microfibers were mainly restricted to the Ca‐alginate system due to its unique and rapid gelation/solidification process. So the application of these helical fibers is limited due to the restricted availability of materials . Additionally, the A of these helical fibers mainly depended on the inner dimension of the collection tube, and thus could not be adjusted once the device was made …”

Microfluidic generation of Buddha beads-like microcarriers for cell culture

“…Recent technological advances in engineering three dimensional (3D) cell cultures have demonstrated prominent improvement in approximation of cell-cell interactions and microenvironmental conditions in vivo, which play a great role in the field of tissue engineering [1][2][3][4][5][6][7][8][9][10][11]. Among them, microcarriers have emerged as novel biomimetic platforms, which offer 3D biomaterial scaffolds for cell encapsulation and aggregate formation [10][11][12][13][14][15].…”