Current methodologies and approaches for the formation of core–sheath polymer fibers for biomedical applications

Abstract

The application of polymer fibers has rocketed to unimaginable heights in recent years and occupies every corner of our day-to-day life, from knitted protective textile clothes to buzzing smartphone electronics. Polymer fibers could be obtained from natural and synthetic polymers at a length scale from the nanometer to micrometer range. These fibers could be formed into different configurations such as single, core-sheath, hollow, blended, or composite according to human needs. Of these several conformations of fibers, core-sheath polymer fibers are an interesting class of materials, which shows superior physical, chemical, and biological properties. In core-sheath fiber structures, one of the components called a core is fully surrounded by the second component known as a sheath. In this format, different polymers can be applied as a sheath over a solid core of another polymer, thus resulting in a variety of modified properties while maintaining the major fiber property. After a brief introduction to core-sheath fibers, this review paper focuses on the development of the electrospinning process to manufacture core-sheath fibers followed by illustrating the current methodology and approaches to form them on a larger scale, suitable for industrial manufacturing and exploitation. Finally, the paper reviews the applications of the core-sheath fibers, in particular, recent studies of core-sheath polymer fibers in tissue engineering (nerve, vascular grafts, cardiomyocytes, bone, tendons, sutures, and wound healing), growth factors and other bioactive component release, and drug delivery. Therefore, core-sheath structures are a revolutionary development in the field of science and technology, becoming a backbone to many emerging technologies and novel opportunities.

Sabina chinensis leaf extracted and in situ incorporated polycaprolactone/polyvinylpyrrolidone electrospun microfibers for antibacterial application

“…The electrospun bers can be applied in biomedicine, pharmacy, food, water treatment, air purication, energy electronics and information engineering. [12][13][14][15][16][17][18][19][20][21] The electrospun bers can be fabricated using natural polymer or synthetic polymer as the main substrate materials and the appropriate solvents based on these different elds. The preparation process shows a greater deal of autonomy and plasticity.…”

Heterogeneous Structural Color Microfibers for Cardiomyocytes Tug‐of‐War

“…The former would generate fiber deformation in axial direction showing with a reversible stretching process, while the latter would make the fiber waggle in a direction perpendicular to the axis or rotate in angles based on the fiber's cross‐section center. [ 51,52 ] It was shown that due to the confinement of microchannel and fixing sites, the fiber exhibited discernible stretching and retracting almost at the axial direction according to the contraction and relaxation cycles of living cardiomyocytes. The optical detection was observed by a fiber optic spectrometer, whose optic probe was focused on the 10% site of the structural color segment.…”

“…In addition, the heterogeneous structural color microfibers could realize single‐cell‐level sensing with a sensitivity at the µN scale, similar to the microfiber‐based cardiac force detection. [ 51 ] Although a sensitivity gap with single‐cell detection methods, such as AFM (reach to 10 pN), [ 8 ] TFM (around nN) [ 11 ] and elastomeric microarrays (around nN), [ 13 ] still exists, the sensitivity of this heterogeneous microfiber could be further improved by series of optimizations. The unique feature of the force–optical visible transformation of these microfibers would greatly simplify the complexity and reduce the expenditure of the whole detection system.…”

Perspective: Covid-19; emerging strategies and material technologies

“…copper nanoparticles, whilst the core of the fibres can be a strong polymer which imparts the strength and toughens the mask. This requires upscaling mass production to suit, and work has already been carried out to achieve this [ 16 , 17 ]. However, in parallel, existing respirators and masks need upgrading to properly inhibit the entry of viral particles, and as with Covid-19, these can be smaller than 100nm.…”