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Multi-Channel Coaxial Electrospinning Needle

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    The distance of the collector from the tip of the needle determines the fiber morphology and bead formation. A closer distance means a stronger electrical field, and the solution jet has less time to evaporate. Very short distances do not cause fiber formation because there is no electrical field, while long distances result in a weak electrical field, and fiber morphology is thicker. Here are some tips to help you choose the appropriate distance for your needs.

    Multi-channel coaxial electrospinning

    A multi-channel coaxial electrospinning needle is a device designed to spin multiple polymers in one cylinder. This type of needle is made from a single cylinder and can be used in a variety of processes, including pharmaceutical formulations and textiles. This new type of needle is designed to process polymers with various types of fillers. It is also suitable for encapsulating bioactive compounds and drugs.

    The multi-channel structure is highly similar to that of biological microstructures. Figure 7 shows typical examples of multi-channel structures: the hollow tube of the lotus root, the microchannel of a polar bear's hair, and the fibers used in ultralight feathers. The anti-cold property of polar bear hair is attributed to the multi-cavum structure. These similarities give multi-channel coaxial electrospinning needle a broad prospect for research and development.

    Besides tissue engineering applications, electrospinning technology is also used to prepare tissue scaffolds. Using this technology, drug delivery to tumors can be facilitated. In cancer therapy, electrospinning needles have proved beneficial in treating tumors. For example, BMP-2-loaded PCL shell-PEG core nanofiber membranes promote osteogenic differentiation in bone marrow stem cells. Moreover, multi-channel coaxial electrospinning needle is capable of encapsulating two different drugs based on their molecular composition.

    Stable continuous fibers produced

    The method of producing stable continuous fibers by coaxial electrospinning needle combines a concentric arrangement of spinneret orifices with a novel micro-compartment design. Commercial manufacturers of spinnerets are used, but some laboratories have designed their own. In a recent study, researchers modified a commonly used ophthalmic needle, the McIntyre cannula needle, to synthesize hollow fibers of nylon 6. These fibers acted as hydrogen peroxide and exhibited various bioactives.

    The fibers F1 fabricated by single-fluid electrospinning exhibited complicated morphology, with some fibers having side-by-side topography. In addition, the quick evaporation of solvent from fluid jets left behind a solid skin on the fibers. This trapped solvent in the fibers caused them to be concave at the surface. Fibers F2 to F4 exhibited a linear morphology with a uniform distribution of size.

    The polymer solution used in the process is introduced into two plastic syringes, one containing the polymer solution, and the other contains the jussara pulp. A common syringe pump controls the flow rate of the two solutions. These are then injected through two concentric steel needles of 0.6 mm inner diameter. The result is a single fiber that expresses the characteristics of each component, in one fiber.

    Applications

    The use of multichannel fibers and tubes has numerous applications in biology. Multichannel nanotubes, for example, are hollow structures with an ultrahigh specific surface area. Polar bear hairs use a multicavum structure to keep perfect temperature and are anti-cold. Moreover, coaxial electrospinning can be used to fabricate multicomponent nanofibers. Multifluidic coaxial electrospinning is a flexible and facilitative method that can produce multiple-component nanomaterials.

    For the melting coaxial electrospinning, a thermal atmosphere was used to warm the inner dopes. The outer and inner dopes are loaded onto separate injectors of different diameters. The thermal atmosphere is necessary to avoid the inner dope from freezing. An infrared lamp was also used to provide the entire thermal atmosphere. These experiments show the potential of coaxial electrospinning needles in gene delivery and other applications.

    In a compound-jet electrospinning process, a polymer solution and an inner paraffin oil are co-issued. The outer liquid forms a liquid jacket around the inner fluid. High voltage disperses an electrical charge in the outer solution, causing multiple jets. The higher conductivity solution carries a greater charge density than the outer solution, which results in increased electrostatic pressure. Viscosity drags the upper solution out of the lower solution.