Microfluidic Fabrication of Polymeric and Biohybrid Fibers with Predesigned Size and Shape

Abstract

A "sheath" fluid passing through a microfluidic channel at low Reynolds number can be directed around another "core" stream and used to dictate the shape as well as the diameter of a core stream. Grooves in the top and bottom of a microfluidic channel were designed to direct the sheath fluid and shape the core fluid. By matching the viscosity and hydrophilicity of the sheath and core fluids, the interfacial effects are minimized and complex fluid shapes can be formed. Controlling the relative flow rates of the sheath and core fluids determines the crosssectional area of the core fluid. Fibers have been produced with sizes ranging from 300 nm to ~1 mm, and fiber cross-sections can be round, flat, square, or complex as in the case with double anchor fibers. Polymerization of the core fluid downstream from the shaping region solidifies the fibers. Photoinitiated click chemistries are well suited for rapid polymerization of the core fluid by irradiation with ultraviolet light. Fibers with a wide variety of shapes have been produced from a list of polymers including liquid crystals, poly(methylmethacrylate), thiol-ene and thiol-yne resins, polyethylene glycol, and hydrogel derivatives. Minimal shear during the shaping process and mild polymerization conditions also makes the fabrication process well suited for encapsulation of cells and other biological components.

Microfluidic Bioprinting for Engineering Vascularized Tissues and Organoids

“…During the past few years bioprinting has emerged as a class of enabling technologies towards the solution of such a challenge, due to their unparalleled versatility of depositing complex tissue patterns at high fidelity and reproducibility in an automated or semi-automated manner 31,32,33 . Sacrificial bioprinting 34,35,36,37,38 , embedded bioprinting 39,40,41 , and hollow structure bioprinting/biofabrication 42,43,44,45,46,47,48,49,50,51,52,53 have all demonstrated the feasibility of generating vascular or vascularized tissues.…”

Recent advances in core/shell bicomponent fibers and nanofibers: A review

“…The only disadvantage of microfluidic method for producing the fibers is its inability to evolve into a high speed and large scale fiber production method, in contrast to what is offered by conventional techniques, i.e., melt spinning or electrospinning. Looking at the works in this field, Boyd et al . have produced a microfiber by conducting a co‐flow in micro‐channels and ultraviolet (UV) reaction polymerization (Figure ).…”

“… Fiber production by UV reaction in microfluidic channel outlet . Reproduced with permission of © Journal of Visualized Experiments.…”

Rapid prototyping of microchannels with surface patterns for fabrication of polymer fibers

“…Recently, researchers have been exploring the possible uses of microfluidics in biomedical diagnostics [9][10][11][12][13][14][15] and biocompatible polymer microfiber fabrication [16][17][18][19][20][21][22][23][24]. Microfluidic diagnostic devices show a lot of promise as they have high portability, reduced analysis time, and inexpensive production compared to benchtop instruments.…”