Microfluidic Spinning Technology Research Articles

Core-Shell Gel Nanofiber Scaffolds Constructed by Microfluidic Spinning toward Wound Repair and Tissue Regeneration.

Growing demand for wound care resulting from the increasing chronic diseases and trauma brings intense pressure to global medical health service system. Artificial skin provides mechanical and microenvironmental support for wound, which is crucial in wound healing and tissue regeneration. However, challenges still remain in the clinical application of artificial skin since the lack of the synergy effect of necessary performance. In this study, a multi-functional artificial skin is fabricated through microfluidic spinning technology by using core-shell gel nanofiber scaffolds (NFSs). This strategy can precisely manipulate the microstructure of artificial skin under microscale. The as-prepared artificial skin demonstrates superior characteristics including surface wettability, breathability, high mechanical strength, strain sensitivity, biocompatibility and biodegradability. Notably, this artificial skin has the capability to deliver medications in a controlled and sustained manner, thereby accelerating the wound healing process. This innovative approach paves the way for the development of a new generation of artificial skin and introduces a novel concept for the structural design of the unique core-shell gel NFSs.

Plant protein fibers obtained by microfluidic spinning technology: An insight into the fabrication, characterization, and digestive characteristics

Although protein-based biomimetic fibers are available, green and inexpensive protein-based fibers remain a challenge to develop. Herein, a microfluidic chip was designed to prepare protein-based fibers using cellulose nanofibers and various plant-derived proteins, including wheat gluten, zein, soy protein, pea protein, and rice bran protein. Furthermore, a comprehensive elucidation of the plant protein fiber formation mechanism was conducted. The results showed that plant protein fibers prepared by microfluidic spinning had smooth surfaces, strong mechanical properties, high thermal stability and antioxidative activity, good digestibility, and low sensitization. Additionally, the strong hydrodynamic shear force produced during microfluidic spinning changed the secondary structure of the protein, which promoted the binding of protein molecules to cellulose nanofibers, thus enhancing the molecular orientation of both protein and nanofiber. Consequently, this study may facilitate the development of natural, environmentally friendly, and functional protein-based fibers.

Ultra-strong and conductive graphene fiber via sacrificial layer technology

Microfluidic spinning technology (MST) is an emerging method specialized in the construction of multi-component and multi-structure fibers. In this study, we designed an ultra-strong coaxial graphene oxide (GO) fiber by employing sodium alginate (SA) as sheath flow via MST. The diameter of the fiber and the arrangement of GO molecules could be controlled by adjusting process parameters. More importantly, the outer SA layer could be removed during a subsequent reduction process of GO, which served as a sacrificial layer to GO fiber formation and enhanced the fiber strength. Ultimately, this could achieve a conductive graphene fiber with a maximum strength of 365.2 MPa and electrical conductivity of 52 Ω/cm via a common wet spinning mechanism.

Preparation of Antibacterial Biobased Fibers by Triaxial Microfluidic Spinning Technology Using Ionic Liquids as the Solvents.

Bacterial infections have become a serious threat to public health. The utilization of antibacterial textiles offers an effective way to combat bacterial infections at the source, instead of relying solely on antibiotic consumption. Herein, efficient and durable antibacterial fibers based on quercetin and cellulose were prepared by a triaxial microfluidic spinning technology using ionic liquids (ILs) as the solvents. It was indicated that the structure and properties of the antibacterial fibers were affected by the type of IL and the flow rates during the triaxial microfluidic spinning process. Quercetin regenerated from [Emim]Ac underwent structural transformation and obtained an increased water solubility, while quercetin regenerated from [Emim]DEP remained unchanged, which was proven by FI-IR, XRD, and UV analyses. Furthermore, antibacterial fibers regenerated from [Emim]Ac exhibited the highest antibacterial activity of 96.9% against S. aureus, achieved by reducing the inner-to-outer flow rate ratio to 0 and concentrating quercetin at the center of fibers. On the other hand, when [Emim]DEP was used as the solvent, balancing the inner-to-outer flow rate ratio to concentrate quercetin in the middle layer of the fiber was optimal for achieving the best antibacterial activity of 93.3% because it promised both the higher encapsulation efficiency and release rate. Computational fluid dynamics (CFD) mathematically predicted the solvent exchange process during triaxial spinning, explaining the influence of IL types and flow rates on quercetin distribution and encapsulation efficiency. It was indicated that optimizing the distribution of antibacterial agents within the fibers can fully unleash its antibacterial potential while preserving the mechanical properties of the fiber. Therefore, the proposed simple triaxial spinning strategy provides valuable insights into the design of biomedical materials.

All-Polymeric stretchable conductive fiber with versatile intelligent wearable applications via microfluidic spinning technology

It remains a great challenge to fabricate all-polymer stretchable conductive fibers simultaneously presenting high mechanical robustness, high stretchability, and high conductivity through convenient and fast process, even though they exhibit great application potential in the intelligent wearable fields in replacement of the traditional metal wires or the liquid metal-based conductive fibers. In this paper, an all-polymeric fiber with core–shell structure is continuously produced through co-axial microfluidic spinning strategy. The composition of the fluids and the processing parameters of MST are regulated to adjust the size of the obtained PU@PEDOT:PSS fiber, and then optimizing its electric properties and the mechanical performances. The polyurethane (PU) elastic shell layer and the H2SO4-doped PEDOT:PSS conductive core provide the obtained composite fiber with a high conductivity exceeding 220 S m−1, as well as an impressive stretchability up to above 400 % strain, thus endowing it with versatile intelligent wearable applications, including the super-sensitive strain sensor for human motions monitoring, textile-based triboelectric nanogenerator for self-powered impact sensing, and the electro-thermal conversion fabric for keep warming.

Microfluidic fiber spinning for 3D bioprinting: Harnessing microchannels to build macrotissues

Microfluidics is rapidly revolutionizing the scientific panorama, providing unmatched high-throughput platforms that find application in numerous areas of physics, chemistry, biology, and materials science. Recently, microfluidic chips have been proposed, in combination with bioactive materials, as promising tools for spinning cell-laden fibers with on-demand characteristics. However, cells encapsulated in filaments produced via microfluidic spinning technology are confined in a quasi-three-dimensional (3D) environment that fails to replicate the intricate 3D architecture of biological tissues. Thanks to the recent synergistic combination of microfluidic devices with 3D bioprinting technologies that enable the production of sophisticated microfibers serving as the backbone of 3D structures, a new age of tissue engineering is emerging. This review looks at how combining microfluidics with 3D printing is contributing to the biofabrication of relevant human substitutes and implants. This paper also describes the whole manufacturing process from the production of the microfluidic tool to the printing of tissue models, focusing on cutting-edge fabrication technologies and emphasizing the most noticeable achievements for microfluidic spinning technology. A theoretical insight for thixotropic hydrogels is also proposed to predict the fiber size and shear stress developing within microfluidic channels. The potential of using microfluidic chips as bio-printheads for multi-material and multi-cellular bioprinting is discussed, highlighting the challenges that microfluidic bioprinting still faces in advancing the field of biofabrication for tissue engineering and regenerative medicine purposes.

A parallel array structured cobalt sulfide/nitrogen doped carbon nanocage/carbon fiber composite based on microfluidic spinning technology: a novel design to boost overall water splitting

Using an innovative microfluidic spinning technology, a parallel array structured p-Co9S8/NC/CF composite electrocatalyst with high performance was synthesized.

Biopolymer-Assembled Porous Hydrogel Microfibers from Microfluidic Spinning for Wound Healing.

Hydrogels are considered as a promising medical patch for wound healing. Researches in this aspect are focused on improving their compositions and permeability to enhance the effectiveness of wound healing. Here, novel prolamins-assembled porous hydrogel microfibers with the desired merits for treating diabetes wounds are presented. Such microfibers are continuously generated by one-step microfluidic spinning technology with acetic acid solution of prolamins as the continuous phase and deionized water as the dispersed phase. By adjusting the prolamin concentration and flow rates of microfluidics, the porous structure and morphology as well as diameters of microfibers can be well tailored. Owing to their porosity, the resultant microfibers can be employed as flexible delivery systems for wound healing actives, such as bacitracin and vascular endothelial growth factor (VEGF). It is demonstrated that the resultant hydrogel microfibers are with good cell-affinity and effective drug release efficiency, and their woven patches display superior in vivo capability in treating diabetes wounds. Thus, it is believed that the proposed prolamins-assembled porous hydrogel microfibers will show important values in clinic wound treatments.

Microfluidic spinning of natural origin microfibers for breast tumor postsurgical treatment

Chinese herb medicines own potential values in breast tumor postsurgical treatment because of their abundant resources and mild health regulating effect; while it is still a challenge to enhance their utilization and effectiveness in breast tumor therapy. Here, we propose novel natural origin microfibers by using microfluidic spinning technology for potential values in breast tumor postsurgical treatment. Premna microphylla (PM), a traditional herbal medicine from natural plant, was chosen as the main component of the microfibers, while curcumin (Cur) with good anti-inflammatory and anti-cancer properties was applied as the encapsulated drug. Due to chemical ion cross-linking in PM, natural origin microfibers could be continuously spun through microfluidics, which would be further woven into a mesh structure. The resultant mesh was endowed with excellent biocompatibility and inhibited properties on breast tumor cell proliferation. By further applied in in vivo experiments, it was demonstrated that the PM microfibers can effectively inhibit the breast tumor recurrence and metastasis after tumor resection surgery. Based on these features, we believe that the natural origin microfibers will broaden the way of postsurgical tumor treatment and play a unique role in biomedical fields.

Preparation of regenerated cellulose fibers by microfluidic spinning technology using ionic liquids as the solvents

Preparation of regenerated cellulose fibers by microfluidic spinning technology using ionic liquids as the solvents

Antibacterial and hemostatic polyvinyl alcohol/microcrystalline cellulose reinforced sodium alginate breathable dressing containing Euphorbia humifusa extract based on microfluidic spinning technology

Antibacterial hemostatic medical dressings have become feasible solutions in response to the challenging wound-healing process. In this study, a novel fiber-type medical dressing with excellent breathable, antibacterial, and hemostatic qualities was created using sodium alginate (SA), microcrystalline cellulose (MCC), polyvinyl alcohol (PVA), and Euphorbia humifusa Willd (EHW) based on microfluidic spinning technology, and the properties of the dressing were characterized. The orthogonal test demonstrates that PVA and MCC can enhance the mechanical properties of the fiber, which is a crucial requirement for fiber assembly to form the dressing. Moreover, the presence of EHW enhances the dressing's antibacterial and hemostatic qualities. The dressings have been proven to have potent antibacterial and hemostatic properties as well as the ability to considerably speed up wound healing and skin tissue regeneration in the in-vitro and in-vivo tests. In conclusion, this innovative fiber-type medical dressing containing SA, MCC, PVA, and EHW has enormous potential for managing wounds caused by bacteria.

Microfiber Fabricated via Microfluidic Spinning toward Tissue Engineering Applications.

Microfibers, a type of long, thin, and flexible material, can be assembled into functional 3D structures by folding, binding, and weaving. As a novel spinning method, combining microfluidic technology and wet spinning, microfluidic spinning technology can precisely control the size, morphology, structure, and composition of the microfibers. Particularly, the process is mild and rapid, which is suitable for preparing microfibers using biocompatible materials and without affecting the viability of cells encapsulated. Furthermore, owing to the controllability of microfluidic spinning, microfibers with well-defined structures (such as hollow structures) will contribute to the exchange of nutrients or guide cell orientation. Thus, this method is often used to fabricate microfibers as cell scaffolds for cell encapsulation or adhesion and can be further applied to biomimetic fibrous tissues. In this review, the focus is on different fiber structures prepared by microfluidic spinning technology, including solid, hollow, and heterogeneous structures, generated from three essential elements: spinning platform, fiber composition, and solidification methods. Furthermore, the application of microfibers is described with different structures in tissue engineering, such as blood vessels, skeletal muscle, bone, nerves, and lung bronchi. Finally, the challenges and future development prospects of microfluidic spinning technology in tissue engineering applications are discussed.

Recent Trends of Microfluidics in Food Science and Technology: Fabrications and Applications.

The development of novel materials with microstructures is now a trend in food science and technology. These microscale materials may be applied across all steps in food manufacturing, from raw materials to the final food products, as well as in the packaging, transport, and storage processes. Microfluidics is an advanced technology for controlling fluids in a microscale channel (1~100 μm), which integrates engineering, physics, chemistry, nanotechnology, etc. This technology allows unit operations to occur in devices that are closer in size to the expected structural elements. Therefore, microfluidics is considered a promising technology to develop micro/nanostructures for delivery purposes to improve the quality and safety of foods. This review concentrates on the recent developments of microfluidic systems and their novel applications in food science and technology, including microfibers/films via microfluidic spinning technology for food packaging, droplet microfluidics for food micro-/nanoemulsifications and encapsulations, etc.

Preparation of Shell/Core Atypical Spiral Conductive Microfibers and Composite Membrane with Good Conductivity and Mechanical Properties

AbstractPoly(3,4‐ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT: PSS) core–shell conductive atypical spiral microfibers are prepared based on microfluidic spinning technology (MST). The formation mechanism of the special‐shaped spiral structure is analyzed. The microfibers and polydimethylsiloxane (PDMS) are composited into membranes, and the microfibers and composite membranes are characterized. The research results show that the conductivity of shell conductive bulbine‐torta (BT) microfibers and the composite membrane are 0.125 1 and 0.880 2 s cm−1, respectively. The maximum strain of a single PEDOT: PSS core–shell conductive BT microfibers is 36.92% under a stress of 213.10 kPa, and the maximum strain of the composite membrane is 107.46% under a stress of 470.56 kPa, indicating that the composite membrane can effectively improve the properties and practicability of the conductive fiber. The change of resistivity of the composite membrane in the stretched state is observed, and it is found that the resistivity first steadily increases and then increases exponentially, indicating that composite membrane has potential application prospects in the fields of thin membrane sensors, electronic skins, smart wearable textiles, etc.

PEDOT: PSS‐Based Microfluidic‐Spun Microfibers for Tunable Release of Acetaminophen via Electrical Stimulation

AbstractTransdermal drug delivery system (TDDS) is effective in alleviating patient's pain and reduces frequent administration. Realizing tunable drug release on fibers/fabrics is important for constructing TDDS platform with good skin affinity and long‐term comfortability. Herein, a conductive fiber consisting of polyvinyl pyrrolidone/sodium alginate/ acetaminophen/poly(3,4‐ethylenedioxythiophene):poly (styrene sulfonate) (PEDOT:PSS) (PVP/SA/AAP/PEDOT: PSS, PSAP) is fabricated by core‐shell microfluidic spinning technology for the controllable release of AAP, a typical pain reliever. Incorporation of conductive fillers endows fibers with microcracks that are responsive to electrical stimulation for promoting drug diffusion and release. The release rate of AAP in simulated body fluid can be improved from 70.81% to 92.07% under electric stimulation, demonstrating a regulable release process enabled by tunable fiber conductivity and applied voltage (0–1.5 V). The drug release kinetic model reveals Fickian diffusion dominates the release process of AAP that generates local concentration difference in the microcracked PSAP fiber with electrical stimulation. This work proposes an accurate fabrication strategy of fibers‐based TDDS that is promising for wearable biomedical electronics and self‐powered on‐demand drug delivery systems.

Spider-inspired regenerated silk fibroin fiber actuator via microfluidic spinning

Wild spider silks exhibit unique supercontraction and reversible contraction/expansion behavior with changes in humidity. These properties are highly desirable in applications such as mechanical actuators and artificial muscles. However, sources of such natural spider silk are insufficient for industrial and practical applications. Research on regenerated protein actuators is highly significant for the development of robotics in biological applications. Herein, we biomimick the novel humidity actuation of natural spider silks by regenerating the abundantly available silkworm silk fibroin using a microfluidic spinning technology. We successfully engineer the fibril alignment and diameter of the desired microfluidic-spun regenerated silk fibers (MRSFs) by controlling the dehydration and shearing of silk fibroins (SFs). These MRSFs exhibit a unique directional initial contraction property once exposed to humidity or organic solvents, which is caused by a transition of the mesoscopic hierarchical structure of SF molecules between the hydrophilic and hydrophobic domains. Further, the MRSFs can be directionally aligned on hydrophobic substrates, thus realizing the facile programming of the folding shapes and deformation manner. The MRSF actuators show a rapid response to humid conditions, as well as high stability and excellent repeatability. We apply the MRSF actuators to smart cargo carriage and convertible structural coloration, offering broad application prospects for biomedical, biocompatible, and biodegradable robotics.

Recent Progress in Preparation and Application of Fibers Using Microfluidic Spinning Technology

AbstractMicroscale fibrous materials with high surface areas and ordered structures have attracted widespread attention recently. Microfluidic spinning technology that can effectively control the sizes, structures, and material compositions of fibers has emerged as a robust approach for the fabrication of high‐performance fibers. In this review, the microfluidic spinning technology used to prepare fibrous materials in terms of preparation principles and geometric configurations is presented. Additionally, several applications of fibers spun by microfluidic spinning technology, especially in tissue engineering, drug release, flexible electronics, water collection, and surgical suturing are introduced. Finally, the current challenges and perspectives of this technology are discussed.

Microfluidic fabrication of β‐phase enriched poly(vinylidene fluoride) microfibers toward flexible piezoelectric sensor

Abstractβ‐phase enriched piezoelectric poly(vinylidene fluoride) (PVDF) films/fibers are often prepared by high‐energy costing methods, including mechanical stretching, high‐electric field or electrospinning. In this study, PVDF piezoelectric microfibers, for the first time, were prepared by microfluidic spinning technology. The β‐phase enriched PVDF microfibers with various diameters could be easily obtained inside the microfluidic channel due to the mass transfer induced phase inversion of the inner PVDF solution. The influence of diameter of the fibers, PVDF concentration of the inner phase and water content of the outer phase on the β‐phase content and crystallinity degree of the obtained fibers was studied in detail. The obtained β‐phase enriched fiber was weaved into meshes. Flexible piezoelectric fabrics were then developed based on these meshes, and further used as in‐situ and real time human motion monitoring. This simple and effective strategy provides a promising microfluidic spinning technique toward the development of functional microfibers and wearable piezoelectric sensors, which may also give some implies for the industrial wet‐spinning of piezoelectric PVDF fibers in the future.

A Phase Inversion‐Based Microfluidic Fabrication of Helical Microfibers towards Versatile Artificial Abdominal Skin

Microfluidic spinning technology (MST), incorporating microfluidics with chemical reactions, has gained considerable interest for constructing anisotropic advanced microfibers, especially helical microfibers. However, these efforts suffer from the limited material choices, restricting their applications. Here, a new phase inversion-based microfluidic spinning (PIMS) method is proposed for producing helical microfibers. This method undergoes a physicochemical phase inversion process, which is capable of efficiently manufacturing strong (tensile stress of more than 25 MPa), stretchable, flexible and biocompatible helical microfibers. The helical microfibers can be used to fabricate bi-oriented stretchable artificial abdominal skin, preventing incisional hernia formation and promoting the wound healing without conglutination. This research not only offers a universal approach to design helical microfibers but also provides a new insight into artificial skin.

A Study on Microfluidic Spinning Technology (MST) Used for Micro Fibre Fabrication

Functional polymeric micro/nanofibers have gained considerable interest as promising materials for the structures that are potentially beneficial in lot of application areas as they possess excellent characteristics such as large surface-area-to-volume ratio, incredibly small pore dimensions etc. Microfluidic developments have currently shown a huge amount of opportunities as revolutionary approaches to create microfiber. By carefully regulating the flow and reaction kinetics in microchannel chip, microfluidic-spinning technology can be applied to generate fibers with tailored characteristics and polymorphic structures. However, this paper features the basic mechanism of micro-fiber production by microfluidic spinning Technology (MST) as well as the principle of Elcectro-Microfluidic Spinning Technology (EMST). Besides, core-shell fiber production by MST is also described in brief. Finally, the advantageous features, application areas and challenges of MST are reviewed briefly in this paper.