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There is a growing demand for polymer fiber scaffolds for biomedical applications and tissue engineering. Biodegradable polymers such as polycaprolactone have attracted particular attention due to their applicability to tissue engineering and optical neural interfacing. Here we report on a scalable and inexpensive fiber fabrication technique, which enables the drawing of PCL fibers in a single process without the use of auxiliary cladding. We demonstrate the possibility of drawing PCL fibers of different geometries and cross-sections, including solid-core, hollow-core, and grooved fibers. The solid-core fibers of different geometries are shown to support cell growth, through successful MCF-7 breast cancer cell attachment and proliferation. We also show that the hollow-core fibers exhibit a relatively stable optical propagation loss after submersion into a biological fluid for up to 21 days with potential to be used as waveguides in optical neural interfacing. The capacity to tailor the surface morphology of biodegradable PCL fibers and their non-cytotoxicity make the proposed approach an attractive platform for biomedical applications and tissue engineering.

Electrofluidics is the unique combination of electrophoresis and microfluidics, which has opened up broad opportunities for bioanalysis and multiplexed assay. These systems typically comprise inaccessible and fully enclosed microcapillary or microchannels, with limited sample loading capacities and no direct access to the solutes within. Here, we investigate the application of multiyarn textile assemblies which provides an open and surface accessible electrophoretic separation platform. Three-dimensional (3D) textile structures have been produced using conventional knitting and braiding techniques from a range of commercially available yarns. Capillary zone electrophoresis separation studies have been carried out on these substrates using fluorescent anionic (fluorescence, FL) and cationic (rhodamine-B, Rh-B) markers. The effects of different yarn surface chemistry, textile fabrication technique, and electrolyte ionic strength on the electrophoretic mobility of the test analytes have been studied. From the broad range of yarns investigated, polyester was shown to have the highest electrophoretic mobility for Rh-B (6 × 10-4 cm2 V-1 s-1) and for FL (4 × 10-4 cm2 V-1 s-1). The braiding approach, being simple and versatile, was found to be the most effective route to produce 3D textile-based structures and offered the potential for selective movement and targeted delivery to different channels. Composite braids made with yarns of differential surface chemistries further revealed a unique behavior of separation and parallel movement of oppositely charged ionic species. We also demonstrate the feasibility to apply isotachophoresis (ITP) on these braided textile substrates to rapidly focus dispersed FL sample bands. Here, we demonstrate the focusing of FL from a dispersed band into narrow band with a 400 times reduction in sample width over 90 s. Owing to the simplicity and reproducibility of the developed approach, textile-based inverted microfluidic applications are expe

3D printing technology has emerged as a platform for rapid prototyping of materials and devices for an extended range of applications. Composite polymer electrodes represent an attractive form of printable materials with task-specific tunability. However, there are currently limited materials available as polymeric-composite electrodes with desirable conductivity and robustness to serve as electromaterials. Herein, we report the fabrication of robust and flexible multilayer 3D printed graphene/polycaprolactone composite electrodes consisting of 10 wt% graphene. This represents a new class of printable biodegradable eco-friendly composite electrodes, with inherent conductivity for the electrochemical studies. The electrode biocompatibility is demonstrated by the electrochemical response derived from the diatom microalgae grown on the graphene/polycaprolactone substrate. We propose that the prepared conductive-biodegradable graphene/polycaprolactone composite can also potentially serve as a scaffold for electrical stimulation in promoting tissue formation for regenerative medicine, as well as bioelectronic applications.

© 2020, © 2020 The Textile Institute. Fluid movement is critical in textile-based microfluidic devices with post-processing approaches commonly used to enhance the wicking rate of textile-based microfluidic devices. In this work, for the first time, we have demonstrated composite fibre approach as an effective, easy, tunable and cost-effective technique with long-lasting effect to change the fibres surface chemistry. This approach incorporates commercially sourced polyester yarns and a low-density polyethylene (LDPE) - liquid crystalline graphene oxide (LCGO) composite fibre integrated into a circular knitted structure. Our technique improves the mechanical properties of the resultant fibres and provides a facile route for tuning the wicking properties of textile-based microfluidics constructs. It was shown that the fluid moves up to six times faster in 3D knitted structures containing the composite fibre as compared to equivalent 3D knitted structures made of polyester yarns only, and the flow rate achievable was found to be proportional to the LCGO loading.

© 2020 Wiley Periodicals LLC There is a growing demand for polymer fiber scaffolds for biomedical applications and tissue engineering. Biodegradable polymers such as polycaprolactone have attracted particular attention due to their applicability to tissue engineering and optical neural interfacing. Here we report on a scalable and inexpensive fiber fabrication technique, which enables the drawing of PCL fibers in a single process without the use of auxiliary cladding. We demonstrate the possibility of drawing PCL fibers of different geometries and cross-sections, including solid-core, hollow-core, and grooved fibers. The solid-core fibers of different geometries are shown to support cell growth, through successful MCF-7 breast cancer cell attachment and proliferation. We also show that the hollow-core fibers exhibit a relatively stable optical propagation loss after submersion into a biological fluid for up to 21 days with potential to be used as waveguides in optical neural interfacing. The capacity to tailor the surface morphology of biodegradable PCL fibers and their non-cytotoxicity make the proposed approach an attractive platform for biomedical applications and tissue engineering.

© 2020 Wiley Periodicals, Inc. An accurate benchtop model was developed to mimic the different forms of human upper airway collapse in adult sleep apnea patients. This was done via modeling the airway through digital imaging. Airway representative models were then produced in two steps via a customized pneumatic extrusion 3D printing system. This allowed the pressure of collapse and planes of collapse to be manipulated to accurately represent those seen in sleep apnea patients. The pressure flow relationships of the collapsible airways were then studied by inserting the collapsible airways into a module that allowed the chamber pressure (Pc) around the airways to be increased in order to cause collapse. Airways collapsed at physiologically relevant pressures (5.32–9.58 cmH2O). Nickel and iron magnetic polymers were then printed into the airway in order to investigate the altering of the airway collapse. The introduction of the nickel and iron magnetic polymers increased the pressure of collapse substantially (7.38–17.51 cmH2O). Finally, the force produced by the interaction of the magnetic polymer and the magnetic module was studied by measuring a sample of the magnetic airways. The peak force in (48.59–163.34 cN) and the distance over which the forces initially registered (6.8–9.7 mm) were measured using a force transducer. This data set may be used to inform future treatment of sleep apnea, specifically the production of an implantable polymer for surgical intervention.

Graphene/polyacrylonitrile (PAN)-based composite fibers, as monofilaments, multifilaments, and yarns, were prepared through a facile solution mixing and wet-spinning method. The PAN-based (PANb) precursor was synthesized via reversible addition-fragmentation chain transfer polymerization with N-isopropylacrylamide as a comonomer. Following wet-spinning, the PANb yarns were carbonized at 900 °C. Scanning electron microscopy images confirmed the presence of a homogenous dispersion of graphene nanosheets inside the polymer matrix. It has been shown that the addition of graphene not only enhanced the thermal and mechanical properties of the PANb fibers, but also improved their graphitic structure after heat treatment. Tensile strength and Young's modulus of the PANb yarns were increased by 28 and 20%, respectively, on addition of 0.5 wt % graphene. Raman spectra demonstrated improvement in the graphitic structure of the carbonized yarns even at low graphene content. These graphene/ PANb fibers show potential as a suitable precursor for the development of next generation carbon fibers. 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47932.

A relative lack of printable materials with tailored functional properties limits the applicability of three-dimensional (3D) printing. In this work, a diamond-acrylonitrile butadiene styrene (ABS) composite filament for use in 3D printing was created through incorporation of high-pressure and high-temperature (HPHT) synthetic microdiamonds as a filler. Homogenously distributed diamond composite filaments, containing either 37.5 or 60 wt % microdiamonds, were formed through preblending the diamond powder with ABS, followed by subsequent multiple fiber extrusions. The thermal conductivity of the ABS base material increased from 0.17 to 0.94 W/(m·K), more than five-fold following incorporation of the microdiamonds. The elastic modulus for the 60 wt % microdiamond containing composite material increased by 41.9% with respect to pure ABS, from 1050 to 1490 MPa. The hydrophilicity also increased by 32%. A low-cost fused deposition modeling printer was customized to handle the highly abrasive composite filament by replacing the conventional (stainless-steel) filament feeding gear with a harder titanium gear. To demonstrate improved thermal performance of 3D printed devices using the new composite filament, a number of composite heat sinks were printed and characterized. Heat dissipation measurements demonstrated that 3D printed heat sinks containing 60 wt % diamond increased the thermal dissipation by 42%.